Publisher’s note: ‘Design Notes” is created to feature the informative and well written documentary inside the User Manual of products to the readership, to offer knowledge and viewpoints that we believe will benefit and even entertain us.

Every product comes with an Owner’s Manual to familiarize the customer with its operations. These documents are often written in a dry style and to the point. But once in a while, we come across vast sections in Manual that reads like a smooth presentation of ideas and juicy description of brilliant technologies, and if we’re lucky, even a story on the challenges faced by the engineers and designers in bringing the concept to fruition.

A prime example of these documents is the ‘Point 8 Owner’s Manual’ written by Nelson Pass in 2013. An amplifier like the XA60.8 is designed to do one thing only, to amplify the incoming signal for driving a pair of speakers. Being a monoblock in design, it features one RCA, one XLR inputs, two pairs of speaker binding posts and an IEC receptacle.

Having addressed the operations of the amplifier in as comprehensive a manner as he could muster, Nelson turned his creative energy to detailing his thoughts on the design of the XA60.8, and juicy details followed. Enjoy the read!

All materials are reprinted by permission.

Submit your Design Notes tips to publisher@dagogo.com.

Pass Laboratories XA60.8

Introduction

For many years there has been considerable faith that if we simply keep improving the measurements of components such as amplifiers then they will sound better. Initially this was truly the case – equipment was sufficiently flawed from an objective standpoint that better measurements matched up with subjective experience.

At some level of objective quality there started to be a disconnect, and some audiophiles began to lose the faith. One of the responses to this was to examine more exotic sources of distortion in the equipment while some others simply worked to continue to reduce the flaws that were already understood. There’s no doubt that some real progress resulted from these efforts, and now you can purchase products at reasonable prices which measure far better than the old stuff.

But the disconnect between the customer’s perceptions and the measurements persists, and there have been cases of state-of-the-art engineering resulting in economic failure, apparently because people didn’t care for the sound.

Well, of course you are dealing with people, and that will complicate any endeavor. The customer wants what the customer wants. I have heard arguments that audiophiles are irrational, that decisions are based on appearance or cost or advertising. Certainly there is plenty of that, and there have been plenty of blind tests that have demonstrated that “audiophiles can’t hear the difference”, at least in the context of that test.

But I don’t think that’s the whole story. My experience is that under the right conditions the customer can often hear the difference, and his observations are not to be ignored.

First, it has to be acknowledged that the science of cognitive perception is still in its infancy, and the ear is not really a microphone and the brain is not a tape recorder. The data we do have on this subject is a little like quantum mechanics – we have to change our view to make sense of the illusions and paradoxes that accompany the interpretation of sensory input.

With regard to amplifiers at least, I think we already have the measurement data in hand. The problem is in our failure to interpret it with respect to human perception.

This puts some emphasis back on listening tests – extensive long-term tests with reliable listeners and familiar equipment and environments. This is not a cheap and easy procedure. Even assuming that the listener(s) really can hear, we still have the vagaries of individual taste, and not a large population of qualified listeners and systems.

In the end, even if we can design around the perceptions of a small qualified listening panel, we are still inevitably aiming at a minority audience in the real world. That’s OK with me – One percent of this market is still a lot of amplifiers.

The thing is, I don’t think the audiophile wants technical perfection. He wants to be happy.

Look at it this way: In the market there are rows of bottled drinking water. Some are contaminated with natural mineral content and carbonated, some have sugar-based substances added, some have been harvested from glaciers. They all appear to be more expensive than gasoline. Where is the pure distilled water? Probably on the bottom shelf, possibly even elsewhere in the store. It seems to be the least popular, even if it is cheaper than gasoline.

Since the release of the X.5 series seven years ago we began working on what has now become the X.8 amplifiers. They embody everything we know, and while I can’t divulge all the details, I can tell you about some things which might interest you.

More is More

There are times when “less is more”, particularly if you are building little “flea watt” amplifiers, where simple Class A circuits sound exceptionally good when the loudspeaker is easy and the musical material isn’t too complex or dynamic. Arguably I pioneered the solid state genre with the 1994 single-stage “Zen Amp” and subsequent designs.

The X.8 series is intended to deliver some of the qualities found in these little amplifiers, but with dramatically more power and accuracy. The formula is simple: More hardware for more power with fewer stages and lower distortion with less feedback. In addition, the various elements of the amplifiers have to be individually adjusted to operate in the harmony that delivers the musical experience.

More Class A

The redesigned output stages of the X.8 series takes the lessons learned from the Xs amplifiers – bigger hardware biased more deeply into the Class A operating region. In turn, the Xs design was inspired by the successes of the X.5 series of amplifiers from 2006.

Two important things emerged with the X.5 series, the first being the value of a large push-pull Class A operating envelope for low distortion and good control of a loudspeaker. Even the Class AB models of the X.5’s had large Class A bias values, so that the performance enjoyed Class A operation at ordinary listening levels.

The second element is the higher level of single-ended Class A bias current applied to the output stage, allowing arbitrary control of the values and ratios of the second and third harmonic characteristic. The subtle qualities of this approach result in a sonic signature which is unique to the X.8 series, but goes back to character of previous amplifiers which have had a particularly successful sound. These amplifiers had good measurement specs – low distortion, wide bandwidth, high current, and so on, but were not “state of the art” in any particular category, simply a good balance of these qualities.

One thing they also had in common was that the distortion they did have was a balance of low order harmonics, dominantly second at low levels and dominantly third at high power.

Are we deliberately creating distortion to achieve this? No. We are optimizing the remaining distortion character of an already low distortion amplifier for a superior musical character.

More Heat Sink

Part of the “more and bigger hardware” is more metal. One of the first things you will notice is that the smaller amplifier models, the X150.8, X250.8, XA30.8, XA60.8 and XA100.8 have new and larger heat sinks (and also more output devices). This upgrade was essential to dissipate the energy of the larger bias currents.

More Front End

Some of the biggest improvements come from the design of the “front end” circuit which contains the first two of the three stages of the amplifier – the input stage and the voltage gain stage. In the X.5 series, all the amplifiers had essentially the same front end circuit, usable interchangeably. This is not quite true of the X.8 series, where each model has subtle differences design to most perfectly complement the differences found in each output stage. Each amplifier in the X.8 series has a individual characteristic depending on the number of devices, heat sinking, supply voltage and push-pull versus single-ended bias currents.The output stages of each model have individual transfer curves and its their favorite feedback figures which must be complemented by the front ends. This was accomplished by using measurements to set a baseline objective performance and then adjusting the circuitry through extensive listening on six different systems.

The front ends use a mix of four each of complementary Jfet, Mosfet, and Bipolar devices by Toshiba. These have been discontinued, but we had the wisdom to have a large inventory of these superior parts. We run these matched input Jfet devices undergenerated for the square-law character, followed by Bipolar cascodes and matched Common Source mode Mosfets.

We have carefully adjusted the bias and loading off the Drains of the gain devices, which selects the most appropriate load-line character and the feedback around the output stage.

The voltage gain stages of the amplifiers also sport much larger heat sinks for much higher bias currents, critical to low distortion and driving the large output stages.

The result is a front end with high stability, low distortion and noise. It has a very high input and is DC coupled. There are no compensation capacitors – in fact there are no capacitors in the amplifier circuit except across the shunt bias regulators and (obviously) the power supply.

More Power Supply

The power supplies for the X.8 series are generally larger than their predecessors. The models X150.8, X250.8, XA30.8, XA60.8, and XA100.8 have a third more storage capacitance and some new CRC filtering to round out the edges of the supply ripple.

We have incorporated additional RF filtering in the AC primary circuits. The supplies still use paralleled fast/soft rectifiers and very large toroidal transformers from Plitron. The power on/off switching is new, with a 400 amp Triac taking the inrush surge and then paralleled by a high current relay. The new system has a stand-by draw in conformance to 1 watt requirements.

The front end circuits of the amplifiers have massively larger power supply decoupling – the ripple is now measured in microvolts. This coupled with interleaved layout techniques has reduced the output noise of the amplifiers by another 10 dB. The range between peak output and average noise floor is greater than 130 dB.

Conclusion

So there you have it. Pass Laboratories celebrates its twenty-second year by presenting the some of the best amplifiers we have ever made. If you have heard the qualities of the highly acclaimed Xs series of amplifiers you will have had a taste of what we offer here – amplifiers that bridge the gap between measured performance and subjective experience: Amplifiers that invite you into the music.

2013 Nelson Pass

CAVE CREEK, ARIZONA, MARCH 14, 2019— Dan D’Agostino Master Audio Systems today announced the Momentum HD Preamplifier, a major upgrade  to the Momentum Preamplifier. The Momentum HD Preamplifier builds on the award-winning platform of the Momentum Preamplifier. The new HD status represents the high dynamic and high definition improvements that have been achieved in this substantial upgrade. The new Momentum HD Preamplifier incorporates advancements in the power supply, audio circuitry, and control sections.

Housed in a separate chassis for maximum isolation, the Momentum HD main power transformer is 33% larger as compared to the original Momentum Preamplifier. A unique winding technology, first employed in the Momentum M400 amplifier, delivers greater power output from the same footprint. Internal circuitry filters RF noise from the AC powerline, and compensates for asymmetric power waveforms and DC on the mains.

A completely new discrete differential FET input stage features two current sources per leg and an input impedance greater than 1MOhm.  This ultra-high input impedance isolates the input stage and thus the entire audio signal path from external variables.

“This new input stage was an engineering experiment that surprised us with the level of fine-grain detail and delicate musical shadings.  The subtleties of voices were rendered with a lushness and richness that were simply unattainable previously“. said Chief Designer Dan D’Agostino.

Taking advantage of the increased power supply capability, the output stages are now operating at a 36% percent higher voltage.  “The increased output voltage has opened up the dynamics on both the micro and macro levels.” D’Agostino continued. “The speed of the dynamic contrasts jump out on a visceral level.”

Also new is the Bluetooth technology featured in the included remote control. The Bluetooth backbone extends the range of the remote by a factor of five and eliminates line of sight limitations that are inherent in IR remote controls.

Newly designed tone and volume control circuitry increases range and precision in both circuits.

Aesthetics have also been updated with the signature copper elements being reshaped to better match the Momentum M400 and S250 amplifiers.

Existing Momentum Preamplifier owners will be able to upgrade to the new Momentum HD Preamplifier electronics enhancements preserving value in their initial purchases.

The Momentum HD Preamplifier will begin shipping in March,2019 at $40,000 USD and upgrades for original Momentum Preamplifier owners will be $7,500 USD. Standard finishes include silver or black.

For more information on Dan D’Agostino Master Audio Systems and its products, please visit dandagostino.com

An Antenna No More!

This past year numerous readers and followers of mine on Twitter and Facebook continually asked me to recommend a budget phono stage, and to this end I had acquired the following phono stages:

1. Parasound ZPhono
2. Cambridge Audio Duo
3. NAD PP2e
4. Musical Fidelity V90-LPS
5. Rega Fono Mini
6. Pro-Ject Audio Phono Box DC

That’s a lot of budget phono stages and, with six turntables and five separate systems here, I am just the staffer at Dagogo to pull this off. So, what’s the first thing you see that’s missing? That’s right … the Schiit Mani. Why did it not make the list? Because it failed one of the very first tests, which shocked me as it is so well regarded internationally, so well reviewed, and so loved by its owners.

A bit about the Schiit Mani: it is small and physically unassuming, so small that it fits nicely in my larger-than-life hands. To look at it, this exercise in minimalist design, from the front with its lone white LED power light it could be just about anything. But its underside tells a different story with its array of load and gain switches, making for a permutational host of settings. One could hardly ask for more and, given its design, asking for less would be a real challenge.

So, what was this test it failed and how was it so noticeable? Well, apart from all the others connected to all the same systems, in the same physical location (my home), the Schiit Mani was the only one to generate noise, and I’m not talking about music.

When I shared my thoughts with folks online about the outcome of my personal shoot-out, a good number of them were disappointed when I could not sing the praises of the Schiit Mani. It was not for lack of trying, as I had acquired one and then had to return it to the company for them to replace it with another, which did not produce, (1) a noticeable hum and, (2) enough RF interference for me to pick up a local AM Hispanic talk radio station, which could be heard through the static. Even with all of the Mani’s worldwide acclaim and with so many satisfied customers singing the phono stage’s praises, I knew I could not be the only one experiencing these issues. And while others and I represent a rather small minority, I could not personally recommend the product since, on my test bed, in my home, it simply did not function as advertised. Under my personal circumstances it was simply unacceptable.

I maintain a very strict policy regarding recommendations and reviews. Upon joining Dagogo, I laid out set of conditions, one of which was that I would not be pressured by the publication, manufacturers and/or public opinion to write anything that I could not personally stand behind.

To my great satisfaction, I learned this past week that Schiit has applied a new RF filter that eradicates the issues I encountered. Just yesterday (Saturday, March 16^th) the updated Mani arrived in the post and I proceeded to run it through with all of my turntables and systems. It passed with flying colors. The sound of silence in the background is so welcome, and apart from Glenn Gould recordings, I can do without the hum.

Present Mani owners know how good the Mani can be, and for those who were put off by reports of the hum and RF interference, if you’re still in the market, I urge you to re-visit as I can, without equivocation, recommend the $129 Schiit Mani as an absolute bargain and able performer.

I am going to have to re-visit my shoot-out among the budget priced phono stages and see where the Schiit lands in the mix. The list at the beginning of this piece reflects the results in order of preference. I listened to all of them extensively, comfortable in the knowledge that the growing number of analogue audiophiles, who are just starting out are in good stead with the options at hand, are clearly not spoiled for choice. For our readers looking to eschew the pesky wall-wart, both the Parasound and Cambridge Audio units make use of internal power supplies and IEC power sockets.

Copy editor: Dan Rubin

About this time last year, I received what EMM Labs referred to as the Reference PRE. The only identification that appears on the preamp are the letters PRE, which I find a bit confusing, given that the earlier design was called the PRE2. While I really did not expect drastic improvements from the PRE over the PRE2, I hooked it up in my system and almost immediately realized that the PRE was a stunning leap forward. The remainder of this review focuses on the differences and how those differences contribute to a more lifelike recreation of the recorded event.

Technical Details

One of the many things that sets the PRE apart from the vast majority of solid-state preamps is the relative simplicity of its design. Whereas most other modern preamps often boast of the number of opamp chips or large-scale integrated circuits in the audio path, the PRE eschews the use of such devices in favor of discrete transistors, which in total are far less than the number of signal path transistors inside a single opamp chip. The audio signal path of the PRE is, in comparison to the well regarded PRE2, purer and more simplified. As the PRE is designed for balanced operation, there are two identical but distinct class A audio paths per channel, one for the positive polarity signal and one for the mirror image negative polarity. Given the claim of purity and simplicity, you may wonder why the motherboard contains hundreds of parts; however, ninety percent of these parts — visible on the surface mount, ceramic printed circuit board — are part of the highly sophisticated power supply regulation system protecting the relatively few transistors in the audio signal path from unwanted external influences. This regulation system ensures that every transistor in the audio signal path is in its own special cocoon of stable and noise-free voltages to give state of the art, low distortion, class A, DC coupled performance. Much like in the EMM MTRX Reference amps, the audio circuitry is characterized by extremely wide bandwidth, extremely fast rise time, and vanishingly low distortion.

Set-up

As good as the PRE sounds straight out of the box, it benefits significantly from some break-in as well as from careful choice of a power cord and proper mechanical isolation. With the wrong power cords the unit can sound somewhat bleached and lacking in tonal color. Two power cords that work superbly are the Jorma Prime and what I think of as the Furutech RED (Furutech DPS-4 wire, which you will need to terminate).  Likewise, depth, focus, and detail benefit from the use of isolation feet. Two products that I have found to work superbly are the Stillpoints Ultra 6 (two at the front and one at the rear) and the CenterStage 2 (in this case two at the front and two in the back). In this particular application, I would go with the Stillpoints Ultra 5 or Ultra 6.

Listening (digital sources)

Bill Evans, Sunday at the Village Vanguard, XRCD.This is probably the best that I have heard this XRCD. In particular, the soundstage is less flat with Paul Motion’s drum set more clearly located behind Scott LaFaro’s bass. LaFaro’s bass is not “in” the left speaker in the same way that I have heard before. Instead, it is set back just a bit. The audience noises are clearly there, lending a sense of occasion and reality, but not as intrusive —just there, like in real life. The piano does not sound quite as big as I recall, but in the past I thought that I heard some overload, which I no longer hear. All good, all musical.

Tord Gustavsen, ECM, CD.First, the cymbals are fantastically detailed — very important here because the drums are so exposed with this quiet Scandinavian piano trio and the cymbal work is often delicate. The bass is big, fat and rich, but clearly located. I can also hear La Faro’s breathing during the bass solo that begins track 2. The detail is incredible. The main tonal difference that I note that between the EMM and the Audio Note preamps is the piano sounds fatter and warmer with the tubes, i.e., the “tube midrange.”  Which is more real? I am somewhat more aware with the PRE that the piano is appropriately considered a percussion instrument, consisting of hammers that strike metallic strings, but this is not in a bad or exaggerated way. It’s just reality. You could tell me that the EMM had some tubes in it and I would probably believe you —the end result is not just very detailed, but very musical as well.

Corinne West and Kelly Joe Phelps, Magnetic Skyline, Tin Angel Records, CD.Two guitars, two voices, one of them the great Kelly Joe Phelps. Likely recorded in live takes in the studio (if my ears are right) and superbly so. I got goose bumps multiple times. The sound of two fine singers, male and female, harmonizing with superb pitch and taste, is one of the most beautiful things that humans can do, particularly when done over the foundation of two very experienced acoustic guitarists playing fine sounding guitars. This preamp opens up every detail. I know where Phelps and West are sitting. I can hear the details of the picks on the strings (the guitars sound freshly strung). I can hear the details of the pronunciation, the closeness of their lips to the microphones, which, taken with everything else, accounts for the shivers down the spine. This is as good as it gets.

Linda Ronstadt, What’s New, FIM CD.What I expected to hear was slightly bright and edgy strings from Nelson Riddle’s terrific arrangements . . . and then the brass would come in with gusto, sparkling but just a bit painful. On both counts, I was wrong. First of all, this sounds as if it was recorded yesterday.  I’d swear that Ronstadt was singing into a Neumann tube mike.   I can hear all the detail of her voice. It has bothered me at times that Ronstadt does not sound like Anita O’Day or Helen Merrill or Chris Connor — the angels of the American Songbook in the 1950’s (to me at least, though, yes, Fitzgerald and Vaughan can bury them in many respects — maybe the flaws and vulnerability are what grab me). Here, Ronstadt sounds like Ronstadt and she has nothing for which to apologize, especially with Nelson Riddle providing the safety net. With that safety net so clean that a pro could transcribe the arrangements by ear. The placement of instruments is nearly 180 degrees across the listening stage and the speakers disappear. What an illusion.

Beethoven, 4^th Symphony, La Chambre Philharmonique. Beethoven on original instruments, the strings played without vibrato, by a chamber orchestra-sized ensemble, can be a dangerous combination when played with too many microphones up close. This live recording does not suffer from the edginess and brashness that often characterize such performances, at least not as heard via the EMM Labs PRE (and EMM digital gear and MTRX amps). The soundstage is quite clear. The antiphonal effect of the strings on either side of the stage is right there and, for me at least, is one of the many new and exciting things I hear with these performances. Most exciting, however, is the very palpable sense of eager enthusiasm that we can hear from the musicians. I find it hard to define the precise musical cues that make this so palpable, but it is there in spades as heard via the EMM gear. Indeed, it is edge-of-the-seat excitement. Is it the exceptional attention to dynamics fostered by Krivine but captured by musicians that are right there with him? Is it the hair’s breadth musical acuity? Is it the occasional edge of an excited bowstring? All of those things? Whatever it is, the thrill of the music comes across in exceptional glory.

Schumann, Symphony 2, Dausgaard, Swedish Chamber Orchestra, BIS SACD. There is no doubt that this is an SACD as it presents a level of spaciousness, air, detail and ease that easily surpasses Redbook CD, especially as presented to us by the EMM gear. Dausgaard’s historically informed performances of standard repertoire have been attracting very positive press (with a few detractors) over the last few years. This Schumann 2^nd is a huge success to these ears. The EMM presents wonderfully grain-free strings over a very wide soundstage. With the smaller orchestra we get the advantage of more colorful blending of the winds with the strings. The prevailing wisdom of the past was that Schumann was a poor orchestrator whose work needed “cleaning up.” With the smaller orchestra, it is hard to see how the objection stands.

The second movement is one of my favorites in the literature and Dausgaard moves it along with exceptional élan. The EMM helps us hear, in particular, the careful attention to dynamic gradations that make this performance special. It also helps us hear the careful attentiveness of the orchestra. The players do not miss a beat — literally — in this performance, which, while brisk, is also somewhat liberal with rubato and expressive hesitations.

Gillian Welch, EMI, CD. The LP of this album has held me almost breathless on multiple occasions. It is almost as if even the most minor squeak of my chair will utterly ruin the quiet, moonlit atmosphere spun by Welch and her companion. I have not in the past been overly impressed with the Redbook version of this album and, apparently, neither was Welch who pushed for the LP issue. While I do not completely understand the why of it, listening now with all EMM gear, the Redbook CD makes me almost as breathless as the LP. This is to suggest that there is clearly a synergy among the EMM pieces and, for that matter, between the PRE and digital media.

Frank Sinatra, Only the Lonely, CD. I have heard some listeners say that early CD’s are sonically among some of the best, which seems silly given the rather huge technical strides that have been made since the early 1980’s, not to mention the continuing growth in understanding how to exploit the differences between digital and analog. Yet this early issue of what is arguably Sinatra’s greatest record sounds just terrific tonight, as it almost always has. Sinatra is perfectly centered and I feel as if I can practically reach out and touch him. That slightly nasal quality is right there, captured in the most flattering light by the ubiquitous Neumann tubed microphone.  At least fifty percent of what makes this album such a gem goes to Nelson Riddle. The instruments are placed very well on the soundstage and sound marvelous. In fact, I had forgotten how intricate some of the wind work is.

Herford, Germany-based T+A is introducing the PA 1100 E, an integrated amplifier with DAC.

According to the company, the PA 1100 E “has both analog and digital inputs and converts digital audio signals into analog signals of the highest quality via the high-resolution and extremely linear 32-bit D/A converter. The PA 1100 E can decode DSD signals (up to DSD 256) and PCM signals (up to 32 / 384), while providing the exceptional power and refinement the E series has become known for.”

The PA 1100 E can be ordered with optional HDMI input / outputs that enable high performance 2 channel amplification / integration into any video display.

Units are available in lacquered matte surface in silver or black with matching side panels.

List of Opamp articles by Doug Schroeder (reverse chronological):

• Eastern Electric MiniMax tube  DAC Supreme: Discrete opamps Survey (June, 2015)
• Audio Blast: Eastern Electric Minimax DAC Plus – discrete opamp rolling (April, 2012)
• Audio Blast: Eastern Electric Minimax DAC Opamp Rolling (March, 2011)
• Audio Blast: Eastern Electric Minimax DAC – Upgrading Op-Amps (January, 2011)

It was a sad turn for opamp rolling audiophiles when both Morningstar Audio, owned by Bill O’Connell, and Alex Yeung of Eastern Electric closed their businesses. Bill was the importer of the Eastern Electric DACs that offered good build quality and that were also good for opamp rolling. The Eastern Electric line of DACs with socketed opamps were valuable as quick and easy DIY opamp rolling projects to improve performance and tune systems. I relished the time spent on maximizing the Minimax DACs, and you can read about it here at Dagogo.com. Thankfully, I own two of the Minimax DACs, a Plus and a Supreme. You can bet I am supremely careful how I roll opamps in them, for there is no longer EE support for them.

Allow me to vent for a moment about a dysfunctional situation in audiophile land. We have shiploads of mediocre cables hawked at all price points. We have a ridiculous number of products meant to do little more than elevate and isolate components, or simply hold them, most with meaningless claims. We have more than enough nonsense products that only the insecure and foolish would buy. Meanwhile, the potential to significantly improve audio systems through discrete opamp rolling languishes, yea is practically dead except for the DIY community. For a pittance compared to exorbitant tweaks, discrete opamps can alter a system’s performance solidly. In addition, they come in a variety of brands and models, like cables, so that they are ideal both in terms of convenience and efficacy to contour systems to the owner’s taste.

Back in 2011-2012, I went on a binge of discrete opamp rolling. Opamps are cheap relative to their efficacy, and at the time I made sure that beyond the samples sent for review I purchased several more for use in my office system. At that time, I recommended the enthusiast simply buy all brands reviewed: Sparkos Labs, Burson Audio and DEXA NewClassD. Together they were a toolkit to tune an audio system easily and inexpensively, one of the most affordable ways to do so. Thankfully, it wasn’t the last of that particular good advice I can give.

The better part of a decade has passed and I still often use the Eastern Electric Minimax DAC Supreme in my system. I can make any speaker system perform admirably by working with the discrete opamps. There seems an almost universal neglect of this method among manufacturers in helping audiophiles enhance their systems. Truly wretched sounding IC opamps are stuck in most components. If audiophiles would hear through comparison how much sonic degradation was happening inside their supposed ultimate build $10K component because of cheap opamps they would be livid. The fact that this is discussed so infrequently is evidence that the average audiophile has no clue how much these devices alter the sound. Others take the stance that because they “think” it would not matter so much, therefore it is not that important — a lazy attitude.

It appears that this easy method is largely ignored in the domestic two-channel HiFi industry. Look at the mind-numbing array of dubious products associated with analogue, and yet supposedly artisanal component makers can’t be bothered to push the limits when it comes to opamps. I understand one reason they won’t, and it’s a very good one. There are plenty of less competent persons out there, people who don’t bother to read directions or follow them, or who try adjustments to systems when in an altered state, i.e. drunk, or the system is on…Then there are those who make a mistake inserting an opamp and simply deny responsibility because they are not willing to pay for repair, foisting onto the company the cost of their mistake. If not for such liabilities more companies might offer the wonder of socketed opamps. For now, we will simply have to endure the barrenness of the landscape, hoping someday to emerge upon a lush world where the pleasure of easy-to-roll opamps is common.

Cheap offers opportunities

Integrated circuit (IC) socketed opamps cost a fraction of discrete opamps, and typically have relatively poor sonic characteristics. I just ranted about companies not using socketed opamps and a primary reason is because a company that builds a quality component will solder the connections, not use socket (unsoldered) connections. Consequently, in building a higher quality component, these manufacturers inadvertently are depriving enthusiasts of the potential to far more significantly improve their component. The manufacturers can boast that the entire board is soldered in premium fashion, all the while the device, the opamp that has been soldered in, can be second rate. It’s a catch-22 situation; the component maker does not want to open themselves up to accusations of building sloppy, slapped together products, but in doing so with opamps the average audiophile who does not have high de-soldering and soldering skills is cut out of the action.

One of the insider secrets of HiFi is that there is not a manufacturer who will admit to using cheap parts, but many do. In an effort to keep costs down corners are cut, and IC opamps are a discreet way of doing so. Many manufacturers have determined that it is not important enough to use discrete opamps. Consequently, while the component may be quite reliable, it is not necessarily an extreme performer — in spite of the brand’s advertising claims. That is not to say it is impossible to build an extreme component without discrete opamps, but in my experience using them would make the product far better.

There are still companies trying to fan the flame of discrete opamps, among them Burson Audio, which makes not only discrete opamps but also audiophile components. One of their latest offerings that is “opamp rolling ready” is the Conductor Reference 3 Headphone Amp/Pre Amp/DAC ($1,799). It sports a pair of the ESS9038 DAC chips for DSD 512, as well as 38-bit 786kHz audio. If you aren’t quite ready to reach for the top shelf components, you may want to try the Burson Playmate Headamp/DAC/Preamp at $399, as it also offers discrete opamp rolling.

The opamps and components under review

During my discrete opamp foray years ago I worked with NewClassD, Burson Audio and Sparkos Labs. I contacted these participants recently and heard from Sparkos and Burson. In addition, I discovered a new participant, Sonic Imagery Labs, via recommendation from an audio forum.

Part of the resurgence in interest for me has been the discovery of a rather unique component offering further exploration of opamp rolling. That most helpful forum participant who recommended Sonic Imagery Labs discrete opamps also mentioned the Kinki Audio EX-M1 Integrated Amplifier as a product having socketed opamps! Looking into it I found that this integrated has been updated to the EX-M1+ model that adds operational flexibility over the original design. The tantalizing prospect of rolling not only a DAC but also an integrated amplifier in one system was too much to ignore; a  review of the EX-M1+ will follow shortly.

In a rare turn of events, the exact same models of discrete opamps are used in the Kinki EX-M1+ Integrated as in the Eastern Electric DACs. This allows fluidity in swapping opamps between these components, and it also greatly reduces the risks of inserting of an inappropriate opamp for these components. It is an ideal scenario for extending my exploration of discrete opamps.

I met up with Dave Cope of Old Forge Marketing and Old Forge Studio at the California Audio Show (CAS) in July 2019.  Dave is the US importer for Pure Audio, a line of audio equipment amplification from New Zealand. After listening in the room Dave had set it up it was very clear to me that this room was one of the two best rooms at the show. Dave has always shared a similar ear to my own and so I was not surprised that I liked the system he brought to CAS. However, what did surprise me was that he was running a solid-state amplifier and getting a sound that had none of the solid-state nasties to which I have been accustomed for decades.

I went back to the room a number of times to be sure that what I was hearing was this good. The amplifier was the Pure Audio One integrated, and I became convinced that this amplifier had something special going on so I requested a review sample.

The Pure Audio One is a 100 watt Class A dual mono integrated amplifier. It has four line inputs as well as a direct input so it may be used as a dedicated power amp. Co-founder Gary Morrison also sent along their dedicated Control 2 preamplifier, which I will review separately.

The One is a rather large integrated weighing in at 26kg (57lbs) and the partnering remote control is a hefty affair in its own right. The artisanship of the amplifier and the matching remote control is first rate.  The One gives the impression of a prestige product that could sit beside far costlier amplifiers. The chassis is made from heavy aluminum and stainless steel mesh. The amplifier runs quite warm, being Class A, so the large heat sinks on both sides of the amplifier with a mostly mesh top allows the heat to dissipate.

Class A amplifiers run hot and soak up a lot of electricity, so does the One. It has an automatic standby mode: if no music signal is being sent, the amplifier will conserve energy until it is woken up by a music signal.

The front panel is minimalist. There is a large smooth volume knob on the right and an input pad on the left for the four inputs and DIRECT IN. There is no power button on the front of the amplifier. On the back, there is a large power switch. The remote control only controls volume up and down. Moreover, Pure Audio uses single-ended (RCA) inputs only, eschewing balanced inputs for reasons they note on their website http://www.PureAudio.co.nz/?page_id=270

Nothing is perfect, so I will get my complaints out of the way.

The back panel layout is perhaps my main gripe about the amplifier. The RCA alignment will require you to separate your RCA cables. The Black and Red are spaced quite far apart as all the black RCAs are aligned in a row on one side, and red aligned on the other. Further, the high quality Cardas speaker connectors do not accept banana plugs, so you will need to purchase adapters if your speaker cables are fitted with bananas. This mystifies me given that bananas are arguably the most common speaker connectors in use today. Fortunately, I had a set of cables with spade/fork connectors just in case this situation arose. I would suggest that Pure Audio include adapters with the amplifier or ensure that dealers stock them. Better yet, look for a high quality 5-way binding post and incorporate that instead.

My last issue is that when you turn the amplifier on, you must always push the SOURCE button. If you are using just one source, the amplifier “forgets” that you were using source 1. Therefore, you must always push the source 1 button. You will forget. You will turn the amplifier on, sit down, and get no sound. Then after you scratch your head, you will say “ahh” and then have to get up and walk over to the amplifier and select number 1. Granted this is probably that bit of exercise most audiophiles need, so the more you forget the healthier you will be. Once you have made your connections you will rarely need to go behind the amplifier and, if you leave the amplifier on in standby mode, you will not need to press the input pad.

Sonic surprise

When I first connected the system and pushed play, I was rather surprised by the valve-like presentation emanating from the amplifier. There was ambiance and depth to my first recording, Loreena McKennitt’s “Lullaby” from her album Elemental, which features Loreena’s vocals overtop of Douglas Campbell’s reading of William Blake’s Prologue intended for a dramatic piece of King Edward the Fourth. One of my complaints about solid state is that it often seems unable to play “gently” and provide an emotional experience with music that should touch your soul. It is usually an abysmal failure in this regard. Yes, solid state can punch you in the kidneys with massive bass slam at obnoxious volume levels, but usually at the expense of delicacy and insight. Thus, I was relieved that the Pure Audio One didn’t manhandle this album and retained the delicacy and allure of Loreena’s vocals and what I often refer to as the “breath of life” that goes missing with a lot of high end audio.

Interestingly, the Pure Audio One sounded more stereotypically “tube” than some tube amplifiers I have auditioned over the years. The fluidity, big tone, ambiance, and portrayal of three-dimensional space should endear the amplifier to tube amplifier fans.

Chantal Chamberland’s “Here Comes the Rain Again” from her album This is Our Time is an excellent recording that, like the Loreena McKennitt, offers a non-digital, you are there experience. With the One integrated, I was hearing big breathy vocals and solid bass lines along with coherency similar to what I remember about my big Line Magnetic 219IA.

Why review the XA200.8

Two years ago, I made a decision that changed my audiophile life. I went to a big box home improvement store where I spied some furniture dollies, and a chill ran down my spine. I was ill prepared should I review some big, immensely heavy amplifiers, ones well past 100 pounds. But if I had some sturdy stands with casters, I could manage to move such amplifiers around and avoid strain on my back. The thought was especially pertinent as I build a lot of systems. My methodology in reviewing is not to wait for a predetermined period of time for a new component placed into a system to settle, or burn in, but rather to get right at it, and I build as many systems as I can over the review period to find out how the component interacts with other gear. I feel this is a superior means of assessing audio equipment versus waiting for something magical to happen. I will learn much more about a component by using it in five systems than I would by playing it for weeks and perhaps making one or two changes to the system.

Because of my methodology, I move all components and speakers regularly. I build new systems every few weeks, and many more discrete systems having slighter changes. It has amounted to hundreds of rigs over the past 13 years. To maintain that pace, I move amplifiers in and out of the system several times during the review period. I needed a way to handle beefy amps efficiently, much the way I determined to put casters on the Vapor Audio Joule White Speakers because they are quite heavy and would be a PITA to move regularly in and out of the listening room. That decision was serendipitous, as the speaker benefited from the approximately 2” lift in soundstage that was conferred by the addition of casters, bringing the speaker’s sound closer to the large towers I have used. In addition, I did not elevate the speakers evenly, but slightly raised the back of the speaker higher to tilt forward the front baffle, thus bringing the top module’s alignment closer to ear level, a maneuver that influences the intensity of midrange and treble relative to the bass output and improves the coherence of the speaker.

The furniture dollies were quite long, made of unpainted 1×4” hardwood, but they had solid, sizable casters. I must have presaged this review, because two years before I used them, I bought, cut down to size, painted and stored those “amp stands.” This is the review for which ambition was rewarded! I was originally going to do a review of the XA30.8, which, were I to move it about the room, is a manageable 88 pounds, but as we shall see destiny demanded that these homemade stands be put into service! As a point of fact, I do not believe in luck (and neither do gambling interests). I do believe the saying, “Luck is when preparedness meets opportunity.”

For those readers who are disgusted by the idea that I am reviewing Pass Laboratories’ largest XA Series Class A monoblocks on furniture casters, please feel free to contain your disdain. The rest of us, who understand that an amp’s sound is no more harmed by placement on cinder blocks or furniture dollies versus a $10K audiophile stand, are managing quite nicely. My informal testing over the years has shown funky furniture to be of little consequence to amps compared to what happens with the power and signal path. Besides, I know things about industry insiders (read manufacturers) who place components in the most bizarre ways but do not publicize it; by their actions they pay little attention to the foundation upon which their gear sits.

Another thing you should not expect me to discuss, much less endorse, is the controversial phenomenon of “burn in.” When I say it is controversial, I do not mean to challenge the idea that capacitors age, or that speaker drivers can have measurable differences over time. I am saying that the hand wringing about how long to burn in an audio component is a waste of time. I will not digress at length here, but feel free to read my Audio Blast: Thou Shalt Not Overemphasize Burn In, in which I put it to test and found it entirely lacking in merit. Few things in audio have failed my Law of Efficacy as spectacularly as burn in. If you feel that I cannot judge a Pass Labs amp without 100-200 hours of burn in time, please keep your excoriating comments to yourself, because I am not inclined to respond to you if you wish to make a stink about it. Now, to those who are more interested in a variety of systems being built to assess this amplifier’s performance, let’s proceed.

How did making homemade amp stands change my life? I wish I was not getting wussy, but at 57 I’m starting to think a lot more about the oversized stuff I’m hauling, first down, then up the basement stairs to and from the listening room. Weight of a component has become a variable I pay more attention to than ever before. I am reminded of Karl, a member of our church and a natural athlete with whom I played basketball for a number of years. When Karl was about 55, he pulled back from participation in the church basketball league. I ribbed him a lot about it, as I was 45 at the time and thought I would push on past that point. Humility comes with age, as does soreness! Four years ago, two years before Karl, my joints and general health dictated that I also quit. Humbled, I admitted to him that I could feel in my bones why his decision was made.

Just as I relish large speakers for their dominant sound, I still enjoy the incomparable headroom of an amplifier with classic design, and that usually means a lot of weight. Nevertheless, I spent the past two years relishing the diminutive First Watt J2 amplifiers. While purposing them for more suitable speakers in the review, I harbored the hope that two would be just enough to handle my beloved Kingsound King III electrostatic speakers. I revealed in my review of the J2 that I preferred it holistically to the beefier XA160.5 and the mighty X600.5 monos. Yet, the J2 did struggle with the King III. I had to push the amps to their limit, and every so often the circuit protection would activate, shutting a unit down. Thanks to First Watt’s robust quality, similar to Pass Labs amps, it never skipped a beat. A brief cooling period and cycling of the power unfailingly brought it back. I wonder if that point may be absent from the J2 review, as with time I pushed it more to its limits in an effort to achieve higher listening levels and better dynamics with the King III. Lately, my goal was to sneak in an article on the new .8 series, perhaps the XA30.8, to retain the tenderness and get a smidgen more power.

I have two members of the Pass Labs team to thank that this is not a review of the XA30.8.  At AXPONA 2018, I opined to Pass Labs President, Desmond Harrington, that I was in search of a bit more power, but without giving up the sweetness of the J2. Knowing my experience with the .5, he said the .8 series was different from the .5 Series, and that I likely would enjoy it much. He encouraged me to tackle the XA160.8, and I concurred. After all, I had some amp stands waiting in the basement. I would wait for the next set of XA160.8 to be made. When the appointed time came to check in on the progress and establish a delivery time, I was in conversation with another Pass Labs employee, Kent English, who said that the set of XA160.8 were slated to be sent to RMAF and would not be readily available. However, he noted, there was a set of XA200.8 monos boxed up with nowhere immediate to go. I balked – after all, they weigh 157 pounds each! He had some great stories to tell me, including how he had to move these amps up a flight of stairs alone and did so by walking them up the stairs, lifting them end over end. He said, “We’ll figure something out. There’s always a way…” I would like to publicly thank these men, as by their encouragement they have made me a most happy reviewer! Meaning no slighting of the XA30.8 or the XA160.8, I am glad that these amps are in my room!

I sound like such a wimp, especially since I still do an hour of cardio or weights six days a week. The big reason I am leery of heavy amps is that I have heard horror stories of guys my age and older screwing up their backs. I do not want to wrench my back and have troubles forevermore. You can’t blame me for such caution, as I know firefighters, mechanics, steamfitters—people who handled heavy stuff —whose backs are shot. I do not wish to be among them, especially from voluntary involvement with mongo amps. But Kent was right, I found a way, which I will explain shortly.

Hot topic

One potential challenge in ownership of such a hot build as the XA200.8 is the operating temperature, which is significant. I recall reading about enthusiasts with Class A amps who rotate them into the system as seasonal heating and cooling demands changed. I can understand the impulse; my room is very energy efficient. The truth is not stretched to say it is built like a vault for acoustic purposes, and is so solid that it only needs 1 supply vent and one return vent. It holds the air so completely that in the heat of summer I keep a polar fleece in the room to take the chill off the air that comes from the AC, and in the deepwinter I go down to the room in shorts and T-shirt, even if it is -20 degrees outside! In that environment, when the XA200.8 are on for 1.5 hours with the door shut, the room becomes toasty. My simple solution is to manage the air temperature by opening the door to the room, which allows the cooler basement air to filter in, allowing for longer listening sessions. Years ago, I used to chafe at the idea of listening with the door of the room open, but now, in an empty nest home, quiet is the norm. With age some things are no longer critical. If the XA200.8 demands room conditioning to hear it, the door stays open and I can listen as long as I wish.

Weight and heat are everyday realities that impinge on the audiophile’s idealism. The first thing I thought about when Kent prompted me to take the XA200.8 for review were those homemade amp stands with casters! Preparation came back to bless me in this review, especially since the XA200.8 has allowed me to push the envelope on system configuration in a way that has not occurred previously. Perhaps you, too, will overcome some shyness to lay hands on these brutal beauties.

Installation

Oh, what travails I have when reviewing (thanks for listening; you are a true friend)! Having unburdened myself, I will explain how I received and installed these amps practically by myself. I’m not supposed to have done this all alone, but Kent encouraged me to not be overwhelmed, as he had to find clever ways of moving the amps himself when help wasn’t available. If he could do it, then I would as well —after all, I have both a hand truck and a furniture dolly!

The thoroughly defensively packaged XA200.8 weighs the better part of 200 pounds, and thus they arrived unscathed from shipping. As with other heavy objects that are on the edge of my capability to move down the steps alone, I have my wife assist by steadying it at each step. She is well aware that were I to stumble it would likely crush her; what a trooper! There is no higher token of true love to an audiophile, but that a wife lay down her life for his listening enjoyment! A bungee cord tight around the thick cardboard outer box was sufficient to keep it pressed to the hand truck.

Once downstairs I kept the lettering on the side of the box upright, presuming that it would orient the amps correctly for removal by opening them up and turning the box over to release the amp. That presumption proved correct, and soon enough the amps were free. Moving them into the listening room required the hand truck, and this time I employed a trick that Kent shared with me. I placed two equally thick paperback books (I did not know paperback Bibles exist! –Pub.) toward the edges of the floor of the hand truck, creating a sizable gap between them. The thick protruding .5” thick ring of the amp’s faceplate meter sat between the protective books as I moved the amp face down on the hand truck, bottom to the outside —perfect! Make sure you have rubber padding on the front of the hand truck when doing such maneuvers or you risk marring the item you are moving. Adding to the elation, when I approached the positioned amp stands, I maneuvered the front thick rubber footers at the bottom of the hand truck directly onto the amp stands. In a slow-motion balancing act, I lowered the amps onto the stands, causing the stands to snap to attention, standing nearly vertical with the footers on the bottom wooden cross member. The large, non-slip footers gripped well enough that they held the amps in place as they were lowered onto the stands. The immense weight on the front casters caused them to sink into the thick Berber carpeting and underlay such that they held their position as the amps and the back of the stands were lowered together. The process was so smooth and relatively easy that I paused for a moment to admire the result, for all the variables lined up perfectly to make it painless. No strained back during this installation! Kent would have been proud of me!

Straightforward

Thankfully, Pass Labs and First Watt amps are among the most user-friendly devices in high end audio to operate, likely a factor in their popularity. Their complexity is internal, their simplicity in use makes ownership a snap, and their reliability is well documented. They are so robust that they can handle mishaps, such as a dead short, that would ruin many other amps.

The .8 series, like the .5 series, retains the clean, industrial façade and fearsome heat sink fins of classic high bias amps. I appreciate the large meter with the powder blue illumination, and although it is not a great departure from the former, I find the front more appealing than the .5 Series. The arguments online about the meters on Pass Labs products provide mild entertainment. If you want to see much ado about nothing, observe audiophiles bickering about meters. The meter on the XA200.8, according to the Owner’s Manual, “…reflects the bias current through the output stage.” For those worried that the meter does not sit in the correct position, the Manual explains that for the X series the wand sits around 10 o’clock, while in the XA series the wand sits around 12 o’clock. My prideful self considers my audio system flawless, because in the first half hour of use the wand migrates from 1:00 to high noon, and it never budges from there.

The consistency of the needle’s pointing northward is so reliable that it reminds me of Quartz Lock indicators on old receivers. When it comes to performance, I prefer a wan Pass wand to a vigorous needle of most brands. That is especially so given the rock-solid reliability of Pass products. A while back, perhaps two or three years ago, I was told confidentially of a different brand’s amplifier that looks like jewelry and sports an obnoxiously large, fancy meter with green illumination— it needed repair three times. You don’t hear of things like that happening to Pass and First Watt products. The most upscale gauge in the world will not redeem an amp that needs repair three times. Knowing the types of glitches that can happen to even high-profile manufacturers, I appreciate the motionless Pass Labs meter for what resides behind it!

Advancements over the .05 Series

If you want to see technological advancement in a seemingly negligible feature, then consider the binding posts of the XA200.8, which have a “wing” style protrusion for easier turning and a pressure release system. Similar to the snap of a car’s fuel tank to indicate that the cap has been closed fully, the binding posts, when cinched down, click and thereby release pressure on the assembly. The spade remains tightly cinched. With as much wrangling of wiring as I did during this review, the posts never loosened a smidgen. They score high marks for visibility and ergonomic efficiency.

There is a thorough discussion of the more formidable improvements in the .8 Series in the download “Point 8 Owner’s Manual” at the Pass Labs website. Here I share salient segments of that discussion. In brief summary, the following improvements are realized in the .8 Series, including larger hardware biased, “more deeply into the Class A operating region.” That means large Class A bias values and, “a higher level of single-ended Class A bias current applied to the output stage.” Consequently, the smaller models have more output devices, and necessarily larger heat sinks.

The “front end circuit” for each amp is unique, versus one shared front-end circuit for all .5 Series amps, as stated: “Each amplifier in the X.8 series has an individual characteristic depending on the number of devices, heat sinking, supply voltage and push-pull versus single-ended bias currents. The output stages of each model have individual transfer curves and it’s their favorite feedback figures which must be complemented by the front ends… The result is a front end with high stability, low distortion and noise. It has a very high input and is DC coupled. There are no compensation capacitors – in fact there are no capacitors in the amplifier circuit except across the shunt bias regulators and (obviously) the power supply. “

Finally, regarding the power supply, the smaller amps have one third more storage capacitance. All .8 models still use very large Plitron toroidal transformers, and have new On/Off switching and high current delay, allowing conformance with the stand-by draw of 1 Watt. The front-end circuits have larger power supply decoupling, “This coupled with interleaved layout techniques has reduced the output noise of the amplifiers by another 10 dB. The range between peak output and average noise floor is greater than 130 dB.”

Even in the vault-like room, the noise level of the XA200.8 through even higher efficiency speakers is to my ear nonexistent. Note that 130dB is in the range of Class D amps! The only time I heard a peep from these monoblock amps was sometimes, when warming up or cooling, a tine of the heatsink fins might ping once or twice, but not continuously. The quietness set the stage for music played at a moderately high listening level to explode from the coveted “black background”— an exciting experience!

Speaking of development: differential design

The owner of a new piece of equipment should carefully read the Owner’s Manual. How many audiophiles do you think follow that advice? Scan the following paragraphs from the XA200.8 Owner’s Manual and see if you can spot an unusual characteristic of the .8 Series design:

“You can hook this amplifier up to any normal loudspeaker without danger of damage. Note, however that both the (+) Red output connection and the (-) Black output connection are live. There is no ground reference at the speaker terminals. The black (-) speaker terminal must never be treated as ground.

This can be important when you are hooking up active sub-woofers to the output of the amp – if you need a signal ground connection then use the white ground terminal provided on the rear panel.”

Did you spot the unusual design feature? Both the Red output and the Black output connection are live; there is no ground at any of the speaker terminals. To the person who hooks up speakers in traditional configurations this would likely be a non-issue, but for the person who is tempted to try alternative wiring configurations, such activity could be disastrous.

Back when I was using a pair of the First Watt J2, Nelson Pass gave me a bit of help to boost performance with the Kingsound King III electrostatic speaker, a lot of speaker for the lower powered amps to handle. He suggested that I join the outputs on each of the J2 amps: “About the J2’s as mono, while the two channels share the supply, you want to keep in mind that Class A circuits like these draw pretty constant power, so technically there is very little difference between running the two channels versus just one. What you might find interesting with the electrostatics is running them in mono by paralleling the two channels, literally connecting the outputs together red-red, black-black and driving both inputs with the same signal.  This will give you twice the current, which is often appreciated at the top end of electrostats where the impedance drops.

The XA200.8 looks like a conventional Class A amplifier, and it has two pairs of outputs, so upon first glance I thought of paralleling the two channels as I did with the First Watt J2 Stereo Amplifier. Thankfully, in conversation with Pass Labs I asked about it and was given a warning not to do so. In other words, after four reviews of Pass amplifiers, I had become lazy and thought I was fully informed on their operation. Obviously not; the incident was a reminder of the onus being on the user to know the Owner’s Manual.

Never “bridge” a differential amp’s outputs

When I learned that the XA200.8 is a “differential” amplifier, I inquired of Pass Labs to provide explanation. Desmond explained succinctly, allowing a quick glance at the topology, “… the amp is effectively bridged inside. So, both terminals are hot (+/-), not unlike balanced cables. The advantages are distortion and noise cancelling, and more voltage swing.”

In the event that you glossed over the above section, do NOT try using both sets of outputs to power one pair of speaker posts with the XA200.8, or with any amplifier employing a dual differential design! You cannot safely sum channels with such an amp!

Nelson further explicated advantages of the design:

“The X and XA amplifiers would be referred to as balanced, as they have both differential inputs and outputs and amplify the signal as balanced, however they are set up so as to accept a single-ended input by simply treating ground as if it was the ‘-‘ balanced input.

There are numerous advantages.  First off, the two balanced halves see the same noise and fluctuations of the supply, and to the extent that the channels are matched, most of any issues caused by this appear the same at the output terminals and thus are not seen by the loudspeaker.

Second, any distortions which are asymmetric will also tend to be cancelled at the output. The feedback loops, if any, can concentrate on the symmetric distortion components.

Third, common mode input noise from the source and environment can be rejected at the balanced input.

Fourth, the high frequency slew rate is doubled, as each side of the amplifier only needs to deliver half of it.

Fifth, the voltages that can be delivered is doubled, so for a given supply voltage you can get 4 times the power. Very helpful when dealing with high power amplifiers and parts which are very high quality but limited in terms of reliability at high voltage.

The downside?  More hardware and cost. Also, black output terminal is not grounded.”

As a result of the enlightening discussion of the features and advantages of a balanced differential design, I feel vindicated for all the years of procuring stereo amps that could be bridged, and preferring to run them that way, as they sounded better when bridged. I also conclude that the differential design is a primary reason why the XA200.8 distances itself from the other amps discussed below.

A tale of two Camrys

Which segues flawlessly to a discussion of automobiles. The 2019 Toyota Camry LE that I drive is my fourth; I started with a dirty gold one, moved to white, then sand, and now a silver vehicle. I am starting to panic that they will run out of colors before I die. They were all outfitted with the same aftermarket features, namely pin striping, mud guards, auto-dimming rear view mirror, body side molding (to protect against door dings), and aftermarket wheels. I have used the same number of Pass family products over the 12 years as Camry LE vehicles.

The most fundamental difference between the 2014 Camry LE that my wife now drives and the 2019 Camry LE that I drive could be described as a shift, or two, away from comfort in the seat and responsiveness in the drivetrain to the opposite in the newer vehicle. The engine and drivetrain of the two vehicles are distinctly different. They are both 4-cylinder, but the 2014 is a 6-speed and the 2019 has an 8-speed transmission. Whenever I get in the older car and merge onto the adjacent highway the car lunges forward like I am exiting the pits at a racetrack. It is unintentional; it takes a few moments to adjust the need for much less foot pressure on the accelerator. The 2019 requires much more foot depression on the accelerator to wind up the transmission in the lower gears to get the vehicle moving, but once in gear for longer travel I appreciate the potential 46mpg versus mid-30mpg.

Pass Labs has traveled a different road than Toyota, as the models of amps through the years have become more subtle, more comfortable, more elegant. The “ride” of the Pass Labs amplifier is decidedly more upscale now than 12 years ago. The X600.5 and even the XA160.5 both were “sporty” in that they would appeal to younger ears itching to hear resolution over tonal suppleness. Now, with the advent of the .8 Series, the lagging tonal richness has been addressed in a convincing manner.

Copy editor: Dan Rubin

Read Part 1

Critical importance of the amplifier to a system

I tried various configurations of equipment to gain an understanding of what the XA200.8 was contributing. Here is one example of a streamlined system intended to have the XA200.8 play a dominant role:

Small Green Computer AP i7 4T Roon Server ($2,855) and SONORE Signature Rendu SE optical ($3,445)

Clarity Cable Supernatural USB 1m (call for price)

Exogal Comet DAC with PLUS Power Supply

Schroeder Method (assembled double IC) Clarity Cable Organic XLR (2m) Interconnects using Audio Sensibility Statement SE OCC Silver XLR Splitter Cables (contact for price)

Pass Labs XA200.8 Mono Amplifiers ($42,000)

Clarity Cable Organic Speaker Cable bi-wired (call for price)

Tri-art audio B series 5 open speaker with crossover ($5,280)

All power cabling was Clarity Cable Vortex Power Cords (call for price)

The result with this system was very good; not the best I was able to achieve with these amps, but better than many systems in the past with dedicated preamps. In 2015 at the time of my review of the Pass Labs XP-20 Preamplifier and X600.5 monos, their total costs were $30,600, and yes, the setup of this review, where an $850 DAC is connected directly to the $42,000 pair of the XA200.8, exiting through $5.3K speakers, is much better. The results show that it is possible to achieve superb results with a highly price-imbalanced system and without a proper preamplifier. It is certainly not recommended as the best way to build a system, as will be seen below. However, it can be done if a person so chooses diligently.

The result also shows that the amplifier(s) have pervasive influence upon the system. Often in the past I have used the consistently appealing Exogal Comet (integrated) DAC and Plus Power Supply, along with the Clarity Cable umbilical, with a variety of amps, but none of those former combinations bested the Eastern Electric Minimax Tube DAC with the XA200.8. Before any reader misinterpret what I am saying, thinking that the Minimax is therefore a “giant killer” that will perform on the level of perhaps a $10K DAC, such as the COS Engineering D1 DAC + Pre-Amplifier, allow me to clarify; I am certainly not saying that the EE DAC is a category buster, or that it can be paired with any old amp and get a remarkable result. Rather, I am saying that the prodigious capabilities of the XA200.8 are such that even when paired with the most modest DAC on hand, the results are highly pervasive. Like a tide surge, the XA200.8 lifts all boats enormously, and fairly determines at what level a pair of speakers will play.

I had similarly wonderful results during my review of the nifty Kinki Studio EX-M1+ Integrated Amplifier, one that is valuable to anyone who wants a high degree of flexibility in system development, such that it could operate as a dedicated preamp, dedicated amp, or integrated amp. In all three modes it was recommendable on its own, although the preferred mode of its operation was as a dedicated preamplifier. I have little doubt that the reason is because in that mode it functioned as a preamp for the XA200.8. Here, then, were two very different products, both paired with the Pass Labs monos, and both products shone their brightest. Does that mean the XA200.8 will likewise cause your components to sound their best? To gain perspective on that the reader may wish to investigate the section of the Tri-Art Audio Series B 5 Open Speaker (and associate components) review, paying attention to its use with the XA200.8 monoblocks. The upshot is that these amps made the $5,300 speaker system sound mighty grand!

Comparision to the Sanders Magtech monos

The Sanders Sound Magetch Mono Amplifiers were a good product to compare to the XA200.8, as both are designed to be statement products that drive speakers with difficult impedance loads. Roger Sanders developed some novel, patented technologies that he claims allow his amp to operate without limitations of more traditional designs. More different specifications in regard to high-power, solid state amplifiers could hardly be found. The Magtech Mono is rated at 2,000wpc into 4 ohms versus the XA200.8’s unrated output into 4 Ohms. I suspect the XA200.8 doubles into 4 Ohms, as would be expected, but Pass Labs is typically conservative on such measurements.

So, what happened in the comparison between the Magtech, with its double take specifications, and the understated XA200.8 as they both drove the Kingsound King III electrostatic speakers? The difference, in terms of what one might expect of the dynamics based on specifications, was surprisingly inconsequential. The macrodynamics of both were excellent, and neither one clobbered the other when it came to the gross operations of powering the speaker.

However, the nuance, refinement, headroom and gorgeousness of the XA200.8 rendered it superior to the Magtech. In comparison the Magtech was like a behemoth Class D, while the XA200.8 was like a monstrous tube amp. When using either with the Exogal Comet directly, both pairs of monoblocks operated near the limit of their output for the gain of the Exogal was not as high as an active preamp. One would think that on paper the Magtech would have blown the doors off the XA200.8, but that did not happen. It was like a photo finish in terms of listening level and authority to drive the King III.

It was anything but a photo finish when it came to intangibles; the King III sounded more erudite and spacious with the XA200.8. Acoustic Alchemy’s “Notting Hill Two-Step” has a punchy bass line that with the Magtech sounded nice and rounded, until heard with the XA200.8. The sense of fullness of an amplifier is difficult to peg until a direct comparison is made. Both the Magtech and the XA200.8 produced the lowest frequencies, but there was less fullness to the notes with the Magtech. The Pass Labs amps also made the bass notes more resonant, versus being flatter notes. Add to this the capacity of the XA200.8 to reveal the extent of the soundstage more deeply, and the instrument, as well as the ambient field it occupied, became more tangible.

More telling are pieces of music such as “Blazin’” by David Dyson. Here, deep LF notes form the strata upon which the electric guitar dances. The Magtech produced these LF notes, but not with nearly as much 3-D character as the XA200.8, which not only had better weighting to the LF notes, but even some roundness of the sort that is usually descriptive of an upright bass. These are extreme examples, which focus on the very bottom frequencies, but the sense of roundedness and fullness via the Pass Labs is heard throughout the spectrum.

Many soprano voices are irritating to me, as they smack of the nasal, whining nature of pop singers. Some female artists have exquisite power, but the recordings are piercing, stabbing in nature, spitting out syllables like daggers, like those of Sarah Brightman. What can be done to help with enjoyment of such artists? My first recommendation is to avoid a Class D amplifier. As a lot, I find class D unable to soften and warm the soprano artists that I consider edgy. The Magtech does better, but it doesn’t quite finish the job. The XA200.8, on the other hand, “matures” these voices by adding copious warmth, while improving subtleties, to keep them from irritating like metal tines of a rake scratching a driveway.

The determinant factor, then, between these two powerhouse amps is not power; for such oddly disparate designs they sound uncannily similar in dynamics. The determinant factor tipping the scales in favor of the XA2008 is refinement. A lesson, then, for those enamored of impressive specs is that the extreme build of the classic Class A was superior. Two thousand watts per channel sells a lot of amps for less efficient speakers, but it was the XA200.8’s 200wpc that drove the King III just as well, and with the nuance of a state-of-the-art transducer.

Comparison to Kinki Studio EX-M1+

The performance of the aforementioned Kinki Studio EX-M1+ is also compelling, that is until it is compared to the XA200.8. To create as fair a comparison as possible, I used the least advantageous system configuration aforementioned for the XA200.8, the DAC-direct method with the cheapest DAC sans preamp, the EE Minimax Tube DAC Supreme, as compared to the EX-M1+ as an integrated amp. My rationale was that this is the least expensive of the optional XA200.8’s setups, and would tell me if there was an inherent differential in performance with the XA200.8 operating with one arm behind its back. The EX-M1+ is a class A/B design and has 215 wpc (versus 200wpc for the Pass). On paper the sound character of the EX-M1+ should be closer to the Pass Labs than the Magtech Monos.

In discussing this comparison, I will begin with an illustration. When my youngest son took possession of my Kawasaki Versys 650 (650CC), we went for a ride, he on the Versys and me on my new Yamaha FJ-09 at 850CC. The larger engine is chestier, deeper, more visceral —it sounds like it will be much more badass, and it most definitely rides more badass! In a similar fashion, upon startup it was immediately obvious that though the specs show the EX-M1+ as being slightly more powerful, it pales in comparison to the XA200.8. That is a good thing for Pass Labs, since the Pass mono amps are about seventeen times more expensive! It would be appalling if the XA200.8 performed like the EX-M1+!

The field of comparison had now shifted to the opposite end; whereas the Sanders Magtech Mono was dynamically powerful, the EX-M1+ was weaker, and while it was closer to the XA200.8 in terms of dynamics, there still remained a sizable gap. One of the most noticeable differences between the two amps pertained to the depth of field and extension of the sound stage. Images as heard through the EX-M1+ seemed relatively shrunken and shallow, lingering in the foreground. Conversely, the XA200.8 thrust back the boundaries of the acoustic space, filled it with more ambient information, and populated it with properly sized instruments and singers. As I have found in the best equipment, the scale of the performance is superior.

This comparison happened after the EX-M1+ had been upgraded through a concerted effort of discrete opamp rolling to bring it to top performance. Yet, the XA200.8 in its native form was dominant in every respect. The EX-M1+ is an intelligently designed integrated amp, but in comparison shows why it is so difficult for even a nifty design to compete well with the overbuilt and thorough design benefits of this .8 Series amplifier.

I may have once again opened myself up to criticism by the elites for pairing an affordable DAC with a megabuck Pass Labs amp. A DAC can lack a high enough output to take full advantage of an amplifier. That is a real concern, and it was the reason why I couldn’t drive the King III well enough to higher listening levels. While the EE DAC was in use, even with the XA200.8 I had to open up the attenuator nearly full when driving the King III speakers. There was some relief using the Exogal Comet; the digital readout during a typical listening session floated between the output level of 90 and 95. For the XA200.8 in use with more difficult to drive speakers an active preamp would surely be preferable. Pass Labs is preparing a preamplifier for review, and I suspect that will resolve all such issues.

A couple of things should be remembered, starting with the reminder that very inefficient speakers are the only ones that will potentially cause the XA200.8 to operate at its upper limits. Even then, there is no slouching, clipping, or sense of strain at all. It is composed and evenly powerful and relaxed as though it has no limits.

The second point to remember is that in my experience all speakers react well to an extremely powerful amplifier with a highly refined design. The easier to drive speakers I used with the XA200.8 benefitted in the same ways as the King III. The PureAudioProject Trio15 Horn1, with its 97dB sensitivity rating, when put through these same amplifier comparisons exhibited similar benefits and,critically, without any noise. All speakers benefit from a well-tempered, powerful amplifier like the XA200.8. Though I am not taking the time to elucidate the experiences of this combination, be assured that the outcome was in conformity with those reported for other speakers in this article: a new reference sound.

When it comes to system building, a shortened signal path with an iconic amp is very difficult to beat. It can be a daunting proposition to build a system using a super-amp without a preamplifier. Would you lay out money for an amp that was perhaps twice the cost you intended on spending, and cut your preamp budget to zero? See what I mean by daunting proposition? It seems a fool’s errand, but when the components are sitting in front of me confidence in the method is reinforced.

By the way, the Kinki Studio EX-M1+ has been billed as something of a wonder-component, as though it is a “giant killer.” Perhaps that is true in regard to some other components, but it is not true in regard to its use as a power amp compared to the XA200.8. The Pass Labs mono amps steamrolled it performance-wise. Were you to drop the XA200.8 onto the EX-M1+ from a great height, as sturdy as the Kinki integrated is, I suspect it would be a tough outcome.That’s basically what happened to it sonically when I “dropped” the XA200.8 on it. Yes, yes, budget audiophiles are absolutely correct, the price differential is extreme. However, the sonic variance was not small, and comparatively the EX-M1+ sound seemed fabricated rather than authentic.

Scary audio systems

Aside from installation and operational issues, there are three kinds of “scary” systems in audiophilia. The negative form of scary audio system is one that sounds so poor you desire to exit the room. Then, there are audio systems that hold you fast to your seat. Why would they be “scary”? I can think of a good reason — the price! It is exhilarating, but potentially scary, to contemplate an audio system that checks all the boxes for scintillating sound yet costs lightyears beyond one’s budget. One fear is that the performance of that system cannot be achieved without spending a small fortune. It was that kind of fear I had when as a postgraduate student I visited a high-end store and had opportunity to hear the Magnepan Tympani IV. I feared that anything so exorbitant would be far beyond my reach in life. I was convinced that if I listened to it, I would be spoiled forever. That was not an entirely unfounded fear, for the possibility of having one’s contentment ruined by an extravagant experience is a possibility. Our aesthetic expectations do not tend to scale down, but up. Experience teaches that it takes a significant amount of money to put up a stellar rig. The odds are vastly against getting a similar outcome on the cheap.

What follows sounds contradictory, but rarely (in my experience, about 1 in 25 systems) is true; the third type of scary system is one that defies convention and is substantially less expensive than might be expected. It often involves an alternative setup that does not follow convention, and thus is unknown to most hobbyists. Once in a while an alternative system is scary good.This has happened to me perhaps ten times in 13 years of reviewing and assembling hundreds of systems. The scary thing about such a system is the realization that many will spendso much more for mere incremental improvements in performance. Thrifty audiophiles desperately wish to have such a system, but they typically do not. The odds are greatly against anyone who does not build many, i.e. dozens, of systems achieving that kind of result.

Might you surmise that the Pass Labs XA200.8 Monoblock Amps are in such a scary system at the moment? Yes, you may. Here is the above system reconfigured to remove the Exogal Comet DAC and insert a dedicated DAC and dedicated preamplifier. The system is not as streamlined as above, however, it took a decided step forward in performance:

Small Green Computer AP i7 4T Roon Server ($2,855) and SONORE Signature Rendu SE optical ($3,445)

Clarity Cable Supernatural USB 1m (call for price)

Eastern Electric Minimax DAC Supreme with Burson V6 Vivid dual discrete opamps ($130/PR) and Sparkos Labs SS3601 single discrete opamps ($78/PR).

Schroeder Method (assembled double IC) Clarity Cable Organic RCA Interconnects (2m; contact company for pricing) using Audio Sensibility Statement SE OCC Silver RCA Splitter Cables ($139/PR)

Tri-art B Series preamplifier ($1,425) and B Series dc linear (tube buffered) power supply ($630)

Schroeder Method (assembled double IC) Clarity Cable Organic XLR (2m) Interconnects using Audio Sensibility Statement SE OCC Silver XLR Splitter Cables (contact for price)

Pass Labs XA200.8 Mono Amplifiers ($42,000)

Clarity Cable Organic Speaker Cable bi-wired (call for price)

Tri-art audio B series 5 open speaker with crossover ($5,280)

All power cabling wasClarity Cable Vortex Power Cords (call for price)

Perhaps as you perused the system listing you saw the “scary” part; the entirety of the system apart from amplification, including a generous estimate of the cabling prices, is approximately $30K, while the amplification is $47K. The amplification represents 61% of total system cost! An even more radical finding is that the preamplifier and tube buffer represent just 4.2% of the entire amplification scheme. The amps represent 95.8% of the amplification scheme!

How many of you are mentally scoffing, “That’s NOT HiFi!” Oh, yes, my friend, it is! When this obscure and obtuse system performs on a level with some of the most well-balanced and costly preamp/amp combinations I have used, it is high end. It is an extremely imbalanced system in terms of resource allocation, yet the performance is as fine as “balanced” setups involving more costly components I have reviewed.

You read that correctly, the preponderance of preamp and amp combos I have used did not achieve the quality of this system. How can that be when I am using a preamp and power supply costing a mere $2,055? Part of the answer has to do with devices called discrete opamps, which can be rolled into certain components with socketed opamps that are amenable to it. They confer a pervasive influence upon the component and offer a variety of ways to contour the sound. The Eastern Electric Minimax DAC Supreme is chock full of them. Read more about this at my most recent article on the subject, “Audio Blast: Return of the Opamp Roller,”and, if intrigued, follow my trail of articles back to 2011-2012 when I first wrote about it here at Dagogo.

Aside from this, there are two advantageous aspects to this system that cause it to leapfrog many traditional systems. One is that the Tri-Art Audio Series B Preamplifier with Linear Tube Power Supply is avant-garde, a passive design with very unusual methods employed in construction, including stripping the plastic from internal parts and stuffing it with lamb’s wool. Now, I’m not a touchy-feely guy in terms of design. I was not terribly impressed by the presence of Bybee products inside the Wells Audio Innamorata, and I won’t give you ten seconds of my interest for brass bowls and baubles to place around the room. Whatever tri-art is doing inside the Series B preamp and tube buffer is not Voodoo audio, it’s efficacious design. Somebody knows their craft, and the proof is revealed when it is paired with extreme amplification. I do expect this little wonder to be outclassed by the Pass Labs preamplifier when it arrives, and this should be no wonder.

Secondly, the amps are vastly overbuilt and ridiculously robust in terms of build, parts quality, and sound. Why should it be surprising, then, if a preamplifier benefits in the same way by association as the aforementioned DAC and speakers? These monoblocks represent not typical amplifier design but extreme amplifier design. Consider that circuit paths are shortened by fractions of inches to improve sound quality. The Pass Labs Supersymmetric circuit has been successful long term partly due shortening each channel’s signal path. Also, instead of being built to spec, the XA200.8 is built to a performance expectation. Subjective listening evaluation is given high priority, seemingly higher than in the past when the amps were largely the product of one designer’s volition. Kent English of Pass Labs shared that the .8 Series departs from the .5 Series in that the older models did not involve group listening evaluation, but the .8 Series does. Amps in the .8 Series were passed around to members of the evaluation team, and the impressions were used to tune the amps’ performance. That was a brilliant move on the part of Pass Labs.

As I intimate above, the result to my ear is markedly different than the .5 Series, which was admirable technically but lacked the warmth that is found in amps such as the Wells Audio Innamorata. I stated previously that the First Watt J2 was the most resplendent of the Pass products I had used. That is no longer true; I hear a beauty in the music with the XA200.8 that dare I say even supersedes that of the J2. Here is an amp that is formidable, and with a personality of the sweet, beguiling First Watt brand. I have never had in my room a solid-state amplifier with such seemingly disparate characteristics expressed in one design, brute force and fawning beauty, and it is captivating!

Welcome to the weird and wonderful world of audio! Would you consider it exhilarating or disturbing to find that one of the best sounds of a dozen rigs established with the Tri-Art Series B 5 Open Speaker was accomplished with the most mockable, lopsided combination of gear? I find it disturbing that I cannot predict such combinations, but I also find it exhilarating to explore the fringes of performance and discover rule-breaker systems. Of course, it is not the set of rules governing electronics theory that is violated, but rather the expectation, the received wisdom of how one is to go about setting up a system.

The shocker with this system was the voluptuous midrange. Beyond generous, more than ample, the rich and seductive midrange with the fabulous coherence of the 8” full range of the 5 Open are an irresistible combination. Evidence of this lay in my inability to advance tracks in conducting assessment of the sound. Normally I can listen to a minute or two of a recording, imprint the sonic character, and add it to the milieu of the playlist as a description of the component under review. Not with this system; the remote sat untouched for the entirety of all tracks.

Happy to be stuck with you

Thirty-four years ago, in more carefree times, Huey Lewis and the News sang, “Happy to be Stuck with You.” If ever there was a time when I was happy to be stuck at home, it is now, for (prepare to have immense pity for me, my friends!) I am “stuck” here doing a long review of the XA200.8 Monos! Pitiful me that I have to extend the listening and note taking time. What a shame! Can’t you sense my distress at this situation?

More like de-stress! When I hear the tried and true combination of the Legacy Audio Whisper DSW Clarity Edition Speakers with the supple, well-muscled XA200.8 it is the auditory equivalent of slipping into a hot tub to relax the muscles. As I listen, I relax, for the waves of sound caress my ears and sound so right.

The odd dance of the DACs was in full swing with this setup, for the very agreeable system featuring the Exogal Comet DAC and the Tri-Art Audio Series B Open 5 Speakers did not seem as “perfect” when I swapped out the speakers for the Whispers. Do not misunderstand me, the performance was quite elevated, with substantial increases in presence, dynamic power, headroom, bass extension, and midrange warmth, which is why you pay much more than the 5 Open, $24,750 for the Whisper XDS version. There was the expected broadening of the center image due to the quad of 7” mid-bass drivers of the Whispers, and the treble was delicate and diffuse due to the ribbon tweeters. It was a prominent move forward in terms of sound quality.

Even though the authority and subtleties of the XA200.8 were on display, I had a nagging feeling that the rig wasn’t fully tuned. Usually when I have a nagging sense of incompletion it is due to some aspect of system building that has been overlooked. It took me a week to recall a trick that had paid off in the past: doing a comparison between use of the software versus the hardware attenuation. Roon’s user interface allows playback with the software volume control set to “Fixed,” and I tend to use that setting when employing an integrated DAC like the Comet. When I switched over to the COS DAC D1+ Preamplifier, which is also integrated, I did not remember to compare the Roon software volume control with the DAC D1+’s internal volume control. I simply kept the setting at “Fixed” on the Roon software and used the D1+’s volume control.

What a mistake that was! After I swapped the controls, using the Roon software volume control and upping the output of the D1+ to max, it was as if a damn had burst! Phenomenal amounts of richness poured forth, the amps seemed to be taken off of conservative mode and put on “performance” mode. Remember the analogy of Toyota Camry vehicles? This was the ideal blend of luxury and performance! I had made this transit back and forth between attenuation devices before, but had never experienced as much of a “rock your world” impact when doing so. I urge those who are skeptical not to get stuck in the objection, “Bits are lost when you use the software volume control,” yada, yada, yada. Frankly, I don’t care if bits are lost or not, I care deeply whether the performance is superior, and I use that which is superior.

One of the first tracks I queued up was Bass Addiction’s “Metropolis,” and I was gratified to hear the Whispers attaining better LF in terms of power and cleanness than with any amp reviewed previously (feel free to look at the list). The results reminded me of when I add the Legacy XTREME XD Subs, each bearing twin 15” woofers, into the system with the Whisper DSW!

This is insanity, right? Wrong; this is unorthodox system building, and it is one way to discover fantastic performance. I went straightaway to vocals, starting with Mandy Moore’s “Forgiveness,” and all traces of the Brittany Spears wannabe had vanished. In its place was a gorgeous, husky-voiced alto with an attitude. This is what I have been after! Her honey-dripping vocals —even though condemning the offending party in song—were so sweet. No amp has ever paired so succulently with the Whispers. Descriptors such as “mature sound” and “fulfillment of ideal” charged through my brain.

I had gone down for a quick listen and it extended to over three hours. It had not culminated before I played the live recording of Lyle Lovett’s “North Dakota,” which had always been raspy and too sharp for my taste, but now held perfect tension between irritation and fascination. That is the way it went with track after track; all the “close but no cigar” singers who were my evidence of a system that had not been perfected were now… perfect. I couldn’t make anyone sound unlistenable, not Alyson Moyet‘s “Invisible,” nor Paul McCartney and the Wings’ “Live and Let Die,”and Simple Mind’s “7 Deadly Sins.” With most amps I am stuck with these songs rendered in an unfulfilled manner. Now, with the XA200.8 Monos and the Whispers, these enjoyable performances with awful recordings could be enjoyed without irritation.

NEXT: Part 3 – Conclusion

Copy editor: Dan Rubin

Read Part 1 and Part 2

With premium program material

The greatest joy of an extreme system is not salvaging poor recordings, it is exulting in superb recordings. Experiencing “you are there” moments, as though planted in front of an artist, is one of the biggest thrills of the high-end experience. In design and execution of my room and system, my goal has been to create the environment of a recording studio such that all extraneous distractions from the outside world are banished. I wish to hear what the recording engineer hears, as though tapping into his mind. I want to envision looking through the glass at the artist performing their piece before the mic.

This system, with the XA200.8 pure Class A monoblocks and the Whisper DSW Clarity Edition speakers, more than any other, gives me the sensation of being right there in the studio. I hear Shelby Lynne’s “Don’t Even Believe in Love” and I think, “What a liar!” I can hear her self-talk not working, because it’s too earnest, too uncertain in her voice. She is getting older, and the spritely, bouncy character is leaving her. But her assurance is increasing. More than with other amp setups, the extra pinch of midrange magic is present with the XA200.8.

Marc Cohn’s Listening Booth is a masterful album, and all the tracks are meticulously recorded. I thrill to the immediacy of “After Midnight” as it is so palpable that you wonder if you could feel his breath; the sense of sitting so close is spooky. The scant percussion and drum work in the background hangs in the air like ornaments dangling around Cohn’s voice. The bass is particularly rich, and the bass solo rendered with a sense of restrained energy that other amps simply have not produced.

One of my favorite live performances is Ginny Owens’ Live from New Orleans, and my favorite song is “Let Love Rule.” The immediacy of the event makes it sacred, and as I have heard this track hundreds of times, the XA200.8 cultivated a distinct richness in her tonality that was lacking with many setups. Without resorting to several cable changes, attempts to tune opamps, or exchanging components, the XA200.8 brought success as Ginny’s every inflection, every intonation was evident, all without the slightest hint of effort.

Guilty pleasures

There is a fair bit of pressure in the industry to showcase systems using what might be termed “audiophile approved” music. Such music must be well recorded and must showcase vocals and acoustic instruments. Solo voice or instrument, symphonic, chamber music, and choral genres are typically approved. Not approved are poorly recorded pieces of any genre, and most rock music, including electric guitar, begins to be questionable. Disdained are pieces featuring synthesized music, which in the opinion of some is utterly worthless in assessment of an audio system. Country music is M.I.A., even though there is now a considerable amount of it that is well recorded. Consigned to the pit of hell are pieces recorded with dynamic compression. Snobbery that often accompanies such distinctions confirms that I am doing a good thing by incorporating both compressed and synthesized music in assessment of systems. Some people never figure out that the problem is their audio system.

I am reminded of an incident that occurred several years ago at a show. I entered a room where there was a pricey, but diminutive system. If I recall correctly, the floor-standing speakers were not four feet tall and had smallish bass drivers. The atmosphere of the room was cultivated to elicit the sense that the system was urbane. I asked to play a CD, and it was not an audiophile approved recording, but was Paul McCartney and the Wings’ “Live and Let Die.” As it played for a minute or two the elder company representative could not contain himself, as he strode over to the system and, removing the disc, declared, “this is garbage! Garbage!” However, the damage had been done— I heard enough in that minute or two to conclude that this was a vastly overpriced and underperforming system. I thought it curious that when I exited, the younger company rep caught my attention outside the room and told me the exact opposite, that the piece was a good selection for assessment. Why did I choose that selection? I was intentionally probing what I saw as weakness in the system, and the music revealed it quickly. I still regularly use that selection in assessment of systems; it was used during this review, and the XA200.8 rendered the song more proudly than any other amp I have used, including Class D amps that are supposed to have phenomenal resolution.

Industry members often keep their personal interest in music tucked away come show time or during reviews. Because they fear the disdain of the politically correct music crowd, they let on as though they are content with the approved musical genres, but in private they listen to their preferred music. It must be acknowledged that there is an advantage to having a fine recording of voices and instruments; I would not be without these for reviewing. Listening to choral pieces through the XA200.8 elevates my spirit. Conversely, putting on any of a dozen or so tracks from the Voices Only series of recordings draws me back down to the earthiness of human singing. More about that in a bit.

I respect the ardor and zeal in production and playback of beautifully performed and recorded music. However, nearly as much can be learned about a system from how it presents poor recordings, or pieces involving more obscure instruments, as long as the music is well known to the listener. I do not disdain approved musical genres; however, I do not spend the bulk of my time listening to them when I am relaxing.

I tend to push back against the expectations of a reviewer’s methods. I previously revealed I do not spend time on burn in. As an aside, some manufacturers know that I eschew that activity, and some do not. I neither advertise nor deny it. To their credit, not a single manufacturer has denied a review for that reason, and they almost universally enthuse that I understood and described the sound of their equipment well. Understandably, some of them, upon learning of my methods, have insisted upon burning in the review component before shipping. I never deny them the pleasure. There is currently a DAC being prepared for my perusal, and the manufacturer will get his two weeks of pummeling it with a signal before I ever see it. Do I think it would make a substantive difference in the outcome of the review? No, not at all, but I do not militate against the pre-review preparations of manufacturers.

A reviewer is supposed to listen over the longer term, i.e., weeks or months, to gain appreciation for what a system is supposed to do, but I don’t. I build more systems than average to gain a better grasp of performance. A reviewer is supposed to use audiophile approved music. Basically, I don’t. I select music in the genres I like that is well recorded. I have the approved music, and will use it, but I do not depend upon it. A critic might say it’s a wonder I can assess a piece of gear. My response is, it’s a wonder that others have such poor methods of assessing gear! I will go so far as to say that the genre of music is secondary as long as it is well recorded, and building more rigs is primary. I think most reviewers have their system assessment priorities backwards.

Last time I looked I had over 800 pieces of music used in reviewing. I have hundreds of fine pieces of music that are both enjoyable and appropriate for assessing systems. However, there are many more pieces of music that elicit joy and strong memories, but would not work the best for my reviewing work. I do so much listening for assessment of performance that I do not often get the opportunity to revisit my “guilty pleasures,” the non-audiophile approved music that I enjoyed decades ago. With the slowdown induced by the Covid-19 crisis I am less rushed to produce reviews and have more time to reminisce while listening. I am going to invite you into a corner of the private listening world of Doug Schroeder, to sit in with me on some of my oldest and fondest synthesized works.

Seriously, Synthesized? Am I trying to rile up the elitists? No, but I make no apologies. In terms of system development, to the same degree that acoustic music can be manipulated to achieve gratification, so also can synthesized music. I have been on the receiving end of the mockery, the dismissal of people who would never use synthesized music to assess an audio system. Well, good for them! As with so many other aspects of the hobby, I tend not to let peer expectations set my agenda. I chart my own path when it comes to the music used to review, or the music I turn to in order to reminisce and elicit strong emotions.

Speaking of strong emotions, synthesized music can do that very thing. You might be laughing now, but it is true. When I was a teen, I swore off popular music, as I discovered how it was rife with immoral lyrics. I turned entirely to instrumental music, and synthesized pieces were represented heavily. For years I had no vocals in my collection! Over time I realized that I was starved for hearing the human voice. Eventually, I applied what might be thought of as a “lyrics filter” to supplement my collection with vocals once again. (Hear hear. –Pub.)

I now turn to some music that I have in CD format up to 35 years old, and have ripped to file for playback. I grew up in the era of ELO, ELP, Pink Floyd, Moody Blues and other heavily experimental, theme album bands. I was selective, choosing to focus on particular selections on albums, and later, CDs that moved me. I was the person who could put on an album, hear my favorite cut or two, pull it off and put on another containing what I felt was an exceptional piece of music. I have no problem butchering an album’s continuity to hear the one or two pieces that I approve. My thought process was, “Why waste my life listening to something I don’t care about?” This makes me no less of an audiophile than the vacuous listener who puts on an album and listens through it, even though it is not redeeming musically or morally.

A short time ago an opinionated forum member attempted to correct me (three times) that very low frequency music (LF) is not worth paying attention to, is negligible in system development, and is likely not very audible. This after I had commented on the beauty of the LF in Pink Floyd’s “Welcome to the Machine.” I looked at his system listing and it featured speakers with loose specs that go down to 40Hz (probably no deeper than 45Hz +/-3dB). I thought, “No wonder this guy doesn’t get LF!” His speakers would be severely challenged to reproduce the bass I am speaking about in the sub 20Hz range, much less render it with fullness and beauty. Played back at a higher level it would be significantly distorted on his system. I can imagine such an audiophile using the approved music, thinking he has close to state-of-the-art sound. When the yardstick used to measure the system is short, it is easier for the rig to seem long on performance! Deficiencies in performance are revealed clearly by pushing rigs to the extreme. Anyone can have a “pretty” sounding system that is not very high performance.

That kind of perspective is endemic in the HiFi community. The truth that few want to acknowledge is that the vast majority of audiophile systems do not sound good with compressed and LF heavy music, and the reason why is that the systems can’t handle it. They are simply not that good. It takes a serious audio system to make such music sound good, and the more extreme the rig, the better it sounds.

The following is a press release from Rotel

AUGUST 17, 2020 – Rotel is pleased to introduce the Michi X3 Integrated Amplifier and Michi X5 Integrated Amplifier as an extension of its current portfolio of Michi products, continuing to deliver on the promise of uncompromised performance and design elegance with exceptional value. The X3 and X5 proudly continue the legacy of nearly 60 years of audio engineering and design experience.

The Michi X3 and X5 are the latest products to showcase the legacy and tradition of Michi, with best-in-class audio engineering methods coupled with the perfect balance of innovation and critical evaluation of every circuit, signal path and component. The exquisite industrial design of the X3 and X5 models are surpassed only by their breathtaking performance. The X3 Integrated Amplifier will be available for purchase in September 2020 with the X5 Integrated Amplifier following in November 2020.

X3 INTEGRATED AMPLIFIER FEATURES AND CAPABILITIES:

• Delivers 350-watts of robust power into 4-ohm and 200-watts to 8-ohm loads driven by a high efficiency oversized toroidal transformer feeding independent analog, digital and power amplifier voltage regulator circuits for optimal power isolation
• The X3 circuits are designed to optimize the signal path to each of the 13 source inputs including XLR, analog, digital, pc-USB, Bluetooth with apt-x wireless streaming and moving magnet phono stage
• Utilizing direct-path circuit topology, the X3 further isolates sensitive audio signals and processing from the high current amplification stage lowering the noise floor and delivering an improved sound field
• The X3 high-resolution screen ensures quick setup of all features and multiple user-selectable configuration options of the run-time display.
• RS232 and ethernet connectivity provide integration with all popular control systems

X5 INTEGRATED AMPLIFIER FEATURES AND CAPABILITIES:

• Delivers 600-watts of output power into 4-ohms and 350-watts to 8-ohm loads with near limitless, controlled, bass energy
• Supports an array of 14 source inputs including analog, digital, XLR, PC-USB with DSD 2x decoding and MQA rendering
• APT-X and AAC high quality wireless Bluetooth streaming and both moving-magnet and moving-coil phono stage
• Digital to analog conversion utilizes an AKM 32 bit, 768khz DAC, achieving meticulous accuracy and timing of the audio
• The front panel graphic display provides easy access to all setup options using the included custom designed signature Michi remote control
• The display is configurable to show operating status, a 12-band graphic EQ or peak power meter
• RS232 and ethernet connection ensure simple integration with automation systems

PRODUCT PRICING:

• X5 Integrated Amplifier – $6,999 USD
• X3 Integrated Amplifier – $4,999 USD

Rotel Michi X3

Rotel Michi X5

ABOUT ROTEL

Rotel audio products are known worldwide for their quality, reliability, value, and, above all, exceptional sound reproduction. Since 1961, Rotel has utilized the resources of its formidable international design team and has manufactured its products in its own sophisticated production facilities. Rotel proudly offers a complete range of electronics that have consistently received critical acclaim and coveted industry awards. With substantial investment in new technologies and manufacturing, Rotel is prepared to meet the challenges of an evolving specialty electronics marketplace.

Too bad I wasn’t born into a rich family or became wealthy by age 35 like a young software entrepreneur. If that had been the case, I would probably have assembled a true high-end audio system before turning 60. Even then it took a few additional years to really get there. First came some pretty good equipment, followed by a decent dedicated room, followed by equipment upgrades, followed by a rebuilt room with dedicated power and acoustic treatments, etc., etc. Along the way I auditioned plenty of fantasy components I simply could not afford, or whose price I couldn’t justify. I was always looking for equipment that, though undeniably still expensive, delivered outsized value.

Throughout this process I had a few anchor components that survived multiple transitions in my system. Of these anchor components, the longest-lived, were my Electrocompaniet Nemo monoblocks. Extremely powerful at 600 wpc into 8 ohms, yet very listenable, they were a great match for the series of power-hungry speakers that came through my door, most notably the B&W Nautilus 800D. Those speakers absolutely craved power, to the point where I actually bi-amped them with both the Nemo monos as well as the Electrocompaniet Nada monos (400 wpc into 8 ohms).

My need for excessive power changed dramatically when I traded the B&W for the Vivid Audio G1 Giya. Though large and in some ways similar in design to the 800D, the Giya is surprisingly efficient, thus affording me the opportunity to explore lower power amps, if you can call 150-300 wpc amps  “lower power” with a straight face. The name Gryphon regularly came up among the amps that caught my attention. I always thought they sounded great at shows, but kept thinking that they were too expensive for me to take the step of auditioning them in my home. That was a mistake.

I might not have taken the leap had it not been for George Vatchnadze of Kyomi Audio. George is a virtuoso concert pianist who clearly operates Kyomi more as a man of passionate about music than a proprietor of a second business. His observations and suggestions about high end audio have never failed to result in audible improvements to my sound. He had used the Gryphon Antilleon Evo with several Vivid speakers and told me on several occasions that he thought they would be a great match with my Vivid Giya. I succumbed to the temptation.

The inside

Because it’s an amp with two channels that come in a single box, the Antilleon Evo is technically a stereo amp. However, it is definitely not the “stereo amp” of yore.This “box” measures  22.5″W x 10.25″H x 23.6″D, weighs 185 pounds, and takes two power cords, just like monoblocks. It’s a true class A design, not an A/B that tries to sell itself as “mostly” class A. It incorporates two 1,500-watt toroidal transformers, twenty bipolar output devices per channel, and 670,000µF of powersupply capacitance. It has monstrous output capability: 1,200 watts of continuous power into a 1-ohm load, and an incredible 5,000 watts peak into 0.5 ohm. Most manufacturers don’t even like to publish information about how their amps perform into half an ohm.

The Antileon Evo was clearly designed by obsessive engineers. The huge transformers are suspended and damped with epoxy. Most internal connections use Gryphon’s Guideline Reference wire, which reportedly employs conductors of gold-infused silver. On the other hand, the output stage is secured to the binding posts with gold-plated copper bus bars.

The outside

Next to the power inlets on the back of the Antileon Evo are two master power switches. You will also find two pairs of large custom binding posts that are very easy to grip and tighten by hand. You won’t find single-ended inputs, as the amp only accepts balanced XLR inputs. Finally, the rear panel includes a 12V link, and the jack to link to a Gryphon preamp’s Green Bias circuitry, which I explain below.

The front panel of the Antileon Evo is mostly acrylic and has six buttons. The far left button is an ON/STANDBY button that, when pressed, activates the amp and reveals a red display behind clear acrylic. This also initiates a self-check that takes approximately 15 seconds and lets you know if there are issues with the amp. The CHECK button at the far right allows you to run the self-check while in full operation. There is also a MUTE button that does exactly that — mutes the sound — which is handy when you want to change out some cables without turning the amp off. However, the remaining three buttons are the most interesting to the dedicated audiophile.

The remaining three front-panel buttons allow you to choose between three bias settings: Bias L (low), M (medium) and H (high). Bias L provides 25 wpc of class A power. This setting is fine for listening at low levels or when simply playing background music, and to my ears sounds better than the vast majority of A/B amps. I mostly used this setting to keep the Evo warm during the day so that it would be ready to play in Bias M or Bias H mode at a moment’s notice in the evening. Bias M and H were the settings I used for serious listening. Bias M delivers 50 wpc of class A power, which I use when blasting certain rock or other highly in-your-face music. Bias H delivers a sumptuous 150 wpc of class A power. I used this for most really serious listening sessions, even most rock, but especially when the music is vocal, orchestral, moody or sophisticated (I’ll expand on this below).

Note that if you use the Antileon Evo with one of Gryphon’s preamplifier models, you can implement a Green Bias setting that results in the preamp controlling the amount of class A  bias in the Antileon. This allows the amp to run with more efficiency when less class A power is needed, hence the Green in Green Bias.

As you’ve probably guessed, the Antileon runs hot, though nowhere near as hot as some other class A amps. For example, the Pass Labs Xs300 was great in winter — I didn’t need to separately heat the room — but in summer it raised the room temperature three to four degrees and ensured that the air conditioning had to run continuously to keep the room at a reasonable temperature.

The following is a press release from Rotel of the McIntosh Group.

ROTEL’S AWARD WINNING STEREO PREAMPLIFIERS ANNOUNCED AS MKII MODELS
Upgraded MKII Audio Circuits and Components Deliver A Higher Level of Acoustic Performance

Tokyo, Japan (May 25, 2021) – Rotel is thrilled to announce new upgraded MKII versions of two of the companies award winning stereo pre-amplifiers with the launch of the RC-1590MKII and RC-1572MKII. Both models feature a host of acoustic and performance upgrades with each acoustic circuit having been critically analyzed and significantly improved by leveraging technologies engineered for the award winning Michi series.

Key component changes include new coupling capacitors directly in the audio signal path to deliver improved frequency response in the DAC circuits. The DAC power supply filter capacitors, volume circuit and XLR balanced circuits also benefited from audiophile grade resistor and capacitor upgrades, isolating the independent DC power supplies, and resulting in a lower noise floor.

Collectively these 2 models benefit from over 75 critical component changes delivering an exceptional level of performance leveraging Rotel’s 60-year history of engineering and manufacturing high performance audio products.

The upgraded models support balanced XLR inputs and outputs, Moving Magnet Phono Stage input for turntable connectivity, analog and digital source inputs, wireless aptXTM and AAC Bluetooth and utilize a Texas Instruments premium 32-bit/384kHz Digital to Analog converter (DAC). Further, both units support MQA and MQA Studio via the PC-USB input and are certified Roon Tested.

A Texas Instruments 32-bit DAC was selected supporting the component changes rendering the audio with improved details and more accurate tonal quality. The changes deliver a larger and more enveloping sound stage surrounding the listener with a genuine and authentic performance. Both models are easy to operate using the included remote control and front panel display. Automatic power controls, signal sensing, fixed volume settings and tone adjustments optimize customization settings. RS232 and IP provide simple control system integration and software updates.

Rotel RC1590MKII

RC-1590MKII

The Rotel RC-1590MKII is a reference preamplifier rending analog and digital sources with natural expression in a wide and open sound stage in stunning clarity. The heart of the RC-1590MKII begins with the power supply featuring dual in-house manufactured toroidal transformers. The transformers are physically and electrically isolated providing dedicated analog and digital supply voltages to all critical circuits through low ESR slit-foil capacitors eliminating unwanted distortion and an extremely low noise floor. Dual RCA and XLR output connection provide the ultimate flexibility including bi-amplification installations. A subwoofer output is also included.

Rotel RC1572MKII

RC-1572MKII

Affordable high-end begins with Rotel’s RC-1572MKII Preamplifier including multiple acoustic upgrades and refinements processing all popular analog and digital sources to an even higher level of performance in stunning clarity with a natural, enveloping sound stage. The RC-1572MKII’s precision engineering begins with Rotel’s ultra-low noise power supply including a large, in-house manufactured toroidal transformer. The transformer design reduces stray radiated emissions and feeds a bank of slit-foil, low ESR capacitors delivering stable current to all sensitive circuits reducing noise and distortion with an ultra-quiet noise floor.

The new MKII models are available in both silver and black colors.

PRICING AND AVAILABILITY

Orders for the RC-1590MKII and RC-1572MKII can now be placed with Authorized Rotel Dealers with shipping expected to begin June 2021 in the United States and Canada, and to the rest of the world shortly thereafter.

Suggested retail price (Excluding sales tax, including VAT as applicable):
 RC-1572MKII: $1,399.99, €1,299.00, £1,150.00
 RC-1590MKII: $2,099.99, €1,949.00, £1,695.00

ABOUT ROTEL

Rotel audio products are known worldwide for their quality, reliability, value, and, above all, exceptional sound reproduction. Family owned since 1961, Rotel has utilized the resources of its formidable international design team and has manufactured its products in its own sophisticated production facilities. Rotel proudly offers a complete range of electronics that have consistently received critical acclaim and coveted industry awards. With substantial investment in new technologies and manufacturing, Rotel is prepared to meet the challenges of an evolving specialty electronics marketplace.

Staccato OSH-DHb dual discrete opamp hybrid horizontal

I need some advice from the community.When I use my discrete opamps, they are generating heat and after an hour or two the room gets too warm. I have to put the AC on full, and my feet get cold. Does anyone know a solution?

That, of course, is a fantasy post to a fictitious forum. Discrete opamps, even those with little heat sinks —yes, some display relatively large ones — throw off negligible heat, though if one places their fingers close, it can be felt. It is a function of the bold new world of the High End that we have opamps sporting huge heat sinks! It reminds me of the Wells Audio Cipher DAC, which uses diamonds to dissipate heat in the signal processing because the switching rate is so high that a material with superior heat dissipation must be used. Don’t laugh at the idea of a beefy looking opamp with heat sinks, because they decimate the performance of cheap chip opamps that are used in most components!

When I first started rolling discrete opamps I never thought that I would still be investigating them ten years later! In the intervening time I have rolled a variety of opamps into the Eastern Electric Minimax DAC Junior, Minimax Tube DAC Supreme and, more recently, the Kinki Studio EX-M1+ Integrated Amplifier. These all take compatible pairs of single and dual discrete opamps, though the quantity varies between DAC and integrated amplifier. Positioning may be problematic for some brands/models in the EE Minimax DAC Junior due to sockets being closer to each other than in the Supreme. As well, in both units there can be diodes or other parts that thrust upward, blocking the opamp from seating properly. This is resolved through use of add-on risers to elevate the opamp a bit more.The representative opamps are from Burson (three generations), Sparkos Labs (two generations), and Sonic Imagery. Refer to my article Audio Blast: Return of the Discrete Opamp Roller for models. Here I explore a fourth company, Staccato Audio, as it also offers compatible, drop-in, single and dual discrete opamps.

Introduction to Staccato Audio

Staccato Audio is a small manufacturer of high performance discrete opamps, led by engineers Jakub Honkisz, who is the founder and project manager, and Morten Oksbierg, who designs the analog circuits. The company is implementing its plan to move beyond opamps to production of a lower power single ended class A solid state amplifier featuring dual mono design with sound quality able to compete with bespoke lower powered amps, such as the Audio Note Kondo ONGAKU. Jakub has offered me a listening test to the rev 3.3, and based on the performance of the Staccato discrete opamps, I accept the offer! If these men are able to pull off a feat as impressive with a preamp/amp combo as with the opamps, their work will be, ahem, noteworthy!

The company has been building opamps since 2017 and the current iteration is a hybrid using the BC560 transistor. Jakub describes some of the methods of the build: “In the production level we are matching input 2SK209 JFETs transistors from the batch of 1000psc, and also adjusting the output current to keep the same load for all three output pairs of 2SK2145. Class A needs to be cooled down, so we use heatsinks, which are good for thermal coupling of the crucial transistors, which are moved to under the heatsink.” The product is called OSH (Open Sound Hybrid). Such fine tuning takes much more production time but makes the opamp highly reliable and exquisite sounding.

Exquisite sound

My testing ground for these opamps was a simple setup involving the following system: Small Green Computer sonicTransporter, SONORE Signature Rendu with systemOptique, Clarity Cable Supernatural USB (1m), Eastern Electric Minimax Tube DAC Supreme, Iconoclast by Belden 4×4 “Generation 2” OCC RCA Interconnects (2m), Kinki Studio EX-M1+, Iconoclast SPTPC (Silver Plated Tough-Pitch Copper) Speaker Cables with locking banana plugs, and the refurbished Ohm Walsh Model F Speakers. All power cords used were the BAV (Belden Audio/Video) Power Cords.

The Ohm Walsh speakers have been an interesting project because they simply have not yielded the transparency that I expected from them. I just finished a review of the latest Ohm F5 speaker and was able to compare the two. The newer hybrid omni is distinctly better in terms of resolution. I have made it a project to elicit more refinement from the Model F. Placing Staccato opamps into the EE DAC and the EX-M1+ has been highly effective at gaining that resolution. Two distinct, powerful shifts upward in openness, richness, fullness, and smoothness occurred, first when I placed the Staccato opamps in the DAC and later when I placed them in the integrated.

The effect on vocals is particularly striking. Joan Baez’s “Diamonds and Rust” is one of my favorites for hearing into a recording, but it was recessed as heard through the Model F prior to the opamp changes. After the Staccato opamps were inserted, it seemed the gain had increased; the speaker could be played at the same listening level with the digital readout of the EX-M1+ several steps lower. At the same time, Joan’s voice was clearer, more evocative, and warmer. I adore products that bring both higher resolution and richer tonality, and these opamps do so. With other opamps, I’ve had to work with mixed sets to be assured of the optimal tonal balance, which is why I recommended purchase of all the brands’ products. But the Staccato opamps bring timbral correctness from the start. I am not saying there isn’t a highly favorable pairing of either the Staccato singles or duals with these other brands of opamps mixed into the DAC or integrated, but I do not feel a need, as with the others, to mix brands to get a highly satisfactory result. These are opamps you can buy and have confidence you will be gaining an exceptional result without having to work with mixing them with another brand. I did hear the dual Burson as well as the dual Sparkos Lab opamps with the single Staccato opamps in the EX-M1+, and in both cases preferred the use of the dual Staccato opamp in their place.

The influence of the Staccato products on the bass is another wonder. The Ohm Walsh Model 7 is not what one might call a prodigious bass performer, as it has a much less braced cabinet than is standard today and the full range driver fires down into the cabinet. It strains to cleanly render contemporary music, such as the single “The Runner” by Foals. Some insist that contemporary music with compression and a heavy LF signature is inappropriate for speakers like the Model F. There is some truth to that, as designs vary markedly, and in order to reproduce all music well a speaker needs to be quite capable. Single driver designs with six-inch or smaller drivers, cramped cabinets, or line source designs with smallish woofers and the like are not up to the task. Push such speakers in terms of listening level and there will be distortion. Often hobbyists blame the music, when the reality is the system is incapable of rendering the music well.

I encourage you to enjoy whatever music you wish on a speaker played at a reasonable level and, if it cannot handle the music, then it’s not all that much of a speaker. However, when the music sounds congealed, distorted, often it is not entirely the speaker at fault but the electronics.The owner cannot tell simply by guessing; one has to compare products, or improve them as with opamp rolling. When I hear the Model F before the Staccato opamps are inserted, I hear a speaker with limitations, but after they are inserted, I hear a speaker with potential. The difference in terms of the bass is a movement from looser, flabbier and more congealed notes to tighter, leaner and more distinct notes. There is less drop-off of low frequencies disappearing due to not being reproduced. Even the mushroom cloud soundstage of the speaker is improved!