CH Precision • L1 Preamplifier and A1.5 Stereo Amplifier

by Dennis Davis | December 16, 2021

© www.theaudiobeat.com

For much of my life, a paraphrase of Hamlet’s soliloquy, Tube-be or not tube-be, has been nothing more than a rhetorical question. The sonic superiority of tube electronics so outweighed the practical advantages of solid-state designs that other considerations simply paled. Sure, solid-state components have always had their benefits. Properly designed and constructed, they seldom suffer catastrophic failure, whereas, all too often, a blown tube fries multiple associated parts. You don’t need to replace silicon output devices, while two matched quartets of KT88s or 6550s is quite an ongoing expense. And then there’s the perennial lure of that tight transistor bottom end.

I came close to solid-state conversion some thirty years ago, when a salesman had me toying with the idea of a Mark Levinson No.29L amp. Ironically, I was saved from that folly when the salesman accepted an offer to write for an audiophile magazine and lost interest in closing my sale. In retrospect, that might have been a stroke of good fortune. Since that time, I’ve seldom dallied with solid-state equipment -- in my system, in the systems of others, or at shows. None of the silicon-based devices I heard seriously challenged my preference for tubes -- until 2014, when I first heard the CH Precision components at the High End Show in Munich.

I reviewed CH Precision’s integrated amplifier in 2019. The I1 pretty much squeezed a CH Precision C1 DAC/control unit into the same package as the company's then-smallest A1 amplifier, maintaining the same circuitry but sacrificing the larger separate power supplies available for the separates, creating a compact and incredibly versatile single-chassis "system in a box." I was duly impressed, but a few changes have taken place in the CH Precision line since then, and the one that caught my attention occurred when the A1 amplifier was replaced by the A1.5, increasing both its dimensions and power output by 50%, from 100 to a more muscular 150Wpc. While most reviewers were enthusing about CH Precision’s top-of-the-line components, I wanted to hear what this new, less costly amplifier could do. As with the I1, the real question was just how much of CH Precision’s fabled M1.1 or monster M10 might have trickled down to its smaller sibling. If the I1 impressed, shorn of all those inputs and that necessary but very useful versatility, just how impressive would the A1.5 be?

At the strong suggestion of CH Precision, I listened to the A1.5 paired with the company's L1 dual-mono line stage, which Roy Gregory reviewed in 2018, making this a review of both products. This is the most expensive gear I have ever introduced into my system, costing about twice as much as the Audio Research Reference 160S amplifier and Reference 6 preamplifier. That’s a sobering thought when you bear in mind that, but for the integrated amplifier, this is the starting point of the CH Precision line. It’s even more sobering when you realize that just like all the other CH Precision components, the L1 and A1.5 can expand and grow. Roy Gregory’s reviews of the other 1 Series components discusses this in more detail, but I’ll just point out that the L1 can be augmented with an outboard power supply, the X1, which adds $17,000 to the tab, after which it can go dual chassis and even dual power supply, for what amounts to a four-box source switch and volume control. It is also highly configurable; you can adjust individual input gain, set input impedance, and establish switch-on volume and maximum levels, among other settings. Like other CH Precision amplifiers, the A1.5 can be user-configured to run as a stereo amplifier, a biamp (single input, twin output) device, a high-current mono or a high-power bridged mono amplifier. Don’t worry -- space didn't allow me to investigate those options. Besides, the whole point of this exercise was to establish how good the "entry-level" CH Precision separates can sound.

Over the years, I have heard pretty much every iteration of the CH Precision equipment -- at shows, at dealers and, increasingly, in homes. I’ve already written about my 2018 visit to Austin, Texas, to spend a day listening to a system built around multiple L1s, P1s and M1s. Since then, the M1 amplifier has been updated to the M1.1 and the company has introduced the 10 Series. Anyone venturing into that territory needs a couple of strong men around to deal with the weight -- and deep pockets to handle the prices, both of which will make your head spin. To give my review of the L1 and A1.5 some perspective, I followed up my listening with a visit to another home system, fitted out with a couple of M10 amplifiers, a four-box L10 line stage and the four-box P1 phono stage, driven in the digital domain with Wadax’s top-of-the-line server, DAC and transport, an experience I will describe on The Audio Beat soon. The sound of that system was incomparable, yet far from diminishing the impression made by the L1 and A1.5, it clarified just what makes the "entry-level" units so satisfying.

As I’ve already mentioned, I’m not going to wade through the finer details of construction, functionality or setup. Roy already covered those in detail. The A1.5 looks like a three-quarter-height and functionally identical version of the M1.1. Essentially, the A1.5 and especially the L1 are units with ultra-short signal paths managed by sophisticated microprocessors. The many operational parameters and niceties are set using an array of seemingly complex menus. Most electronics can be up and running without disturbing the owner's manual. Do that with the CH Precision pieces and you will, at best, miss out on some of their capabilities, and at worst you could be met with silence. However, although those multiple menus might seem impenetrable, if you think in operational terms, they are entirely logical. That logic is best learned by watching and listening to someone who knows what they are doing. A half-hour going through the settings with your dealer, and you can file the manual away.

I began my listening with exactly the kind of music you might expect from a tube devotee who often finds himself pining for a little more weight and drive on bass and drums. Given solid-state's assumed superiority in bass speed and weight, and the A1.5 amp's and L1 preamp's significantly higher price tags, failure to shine when it came to producing fast, dynamic and tuneful bass would have made the CH Precision duo a non-starter. It quickly became apparent that I wasn’t going to be disappointed.

As soon as everything was fully warmed up, I reached straight for Led Zeppelin to get a quick assessment. I have owned or borrowed every pressing of Led Zeppelin II, including a friend’s white-label promo of the rare Robert Ludwig “hot” mastered early Atlantic original, the current Atlantic reissue and the Classic Records version, but ultimately I settled on the UK plum-label version [Atlantic 588 198] as the second-best (after the Ludwig mastering) and more affordable choice. "Whole Lotta Love" can make smaller, less dynamically capable systems sound like they are almost literally coming apart. Over the years, I have heard this LP sound better and better in my system, as generations of new electronics have become more refined and robust. Yet the limitations of reproducing stadium-sized music on a relatively small system left me lusting for larger speakers than my space accommodates. That was until I put the CH Precision electronics into my system and Zeppelin went straight from playing in a large club to staging a show in a massive amphitheater -- with me sitting up front. Led Zeppelin II’s big sound has never been more impressive in my listening room. Looking at my listening notes now, I find the scrawled question, “Can I live without this amplifier?” For the first time, I could crank the music up to as loud as I could stand. Instead of worrying about distortion, I switched to whether the bass drivers could withstand the newfound excursions.

The A1.5 has the same power rating as the Audio Research Reference 160S, which has been my reference, so output power wasn't responsible for what I was hearing. But the difference was so big and so profound that I was almost tempted to stop the review right there. But I pressed on, playing another demo LP. I always check the sound of the bass guitar on Janis Ian’s Breaking Silence [Analogue Productions APP 027] with every new component I slot into the system. I have heard it played on systems with much larger speakers and more muscular amplifiers (at least on paper). I know that the sound I get out of my Wilson Yvettes driven by any number of tube electronics is magical, but the level of testicular failure can leave me pining for solid state. The CH Precision L1 and A1.5 are the first preamp and amp I have heard in my system that retain the magical warmth of tubes with Chad Watson’s bass guitar, while at the same time exhibiting the full-bodied muscularity that can be felt as clearly as it’s heard. In the same way, the soundtrack album Thin Red Line [RCA 09026 63382 2] has been in my collection for many years, as the Terrence Malick film is a favorite. I’ve heard it on large and impressive systems and it is a jaw-dropping experience, but at home it has never made the grade, sounding diminished in size and impact, begging for speakers with a couple of 12” bass drivers. Just as the film demands to be seen on the big screen, the music fares best on a large system, a system that makes you feel the ground moving below your feet, a system that instills a sense of fear and wonder. The CH Precision L1 and A1.5 will not make small speakers large, but they do make them perform at their peak, delivering every last ounce of the bottom-end authority they possess. Despite my modest system, and for the first time in my own home, this equipment made the score sound cinematically believable.

Gripped with excitement, I took the CH Precision duo for a spin with some of the most outstanding mono blues albums on my shelves. Lightnin’ Hopkins’ Lightnin’ and the Blues [Herald LP-1012] is, for all intents and purposes, unobtainable. The last time I checked, a nice copy would set you back at least $500, and that was years ago. More affordable but just as impressive with the CH Precision electronics was Slim Harpo’s The Original King Bee [Analogue Productions APB 114], a compilation of Harpo’s greatest hits. I rounded out the session with The Best of Muddy Waters [Chess 1427]. These albums all share a heavy bass line that, although rolled off at the lowest frequencies, gains speed, shape and attack as a result, retaining an insistent rhythm and potency found only on the best of these mono blues recordings from the pre-stereo period. These recordings were made on all-tube decks and respond magnificently to tube electronics. They also work especially well to demonstrate the worst of solid-state sound -- reflecting the lack of body and the absence of that almost magical shape to the music, once it’s subjected to silicon devices. Did they reveal the semiconductor sound of the CH Precision electronics? The short answer is an emphatic “no.” The slightly longer answer is that the CH Precision A1.5, in particular, tightened up the sound a bit but retained all the sexy, round fullness and dynamic range that these early recordings captured so well.

As good as the bass speed and punch of the L1 and A1.5 are, the most impressive things about these electronics actually became obvious with less-bass-heavy music. After listening to disc after disc of music aimed at finding strengths and weaknesses in the CH Precision products, I took a break from my reviewing agenda to just listen to music I loved. I put on Mozart’s 20th Piano Concerto with Martha Argerich on piano and the Orchestra Mozart led by Claudio Abbado [Deutsche Grammophon Gesellschaft 479 1033], one of my favorite Mozart recordings. It was recorded live at the Lucerne Festival in 2013; I considered the performance well captured -- better than much of the Argerich canon but not up to the standard of DGG’s best recent sound. With his 20th, Mozart built energy in a way never achieved before in classical music. It was Mozart’s earliest “demonic” piece, foreshadowing a similar mood in Don Giovanni and the Requiem. The first movement progresses forward with surging, agitated syncopations. That sense of shifting progression is heightened by Mozart’s practice of emphasizing the rhythmic energy towards the end of a phrase. The second, slow movement opens with unforgettable music known to many as the background music to Salieri’s madness scene in the movie Amadeus.

My choice of the Mozart CD was without premeditation. It was not selected for any purpose other than taking time off from kick-drum comparisons to kick back and enjoy some other music. But instead of helping me kick back, it kicked me to attention. Despite the many times I have listened to this performance -- and I thought I knew it by heart -- as soon as I cued it up with the CH Precision equipment, I experienced several revelatory insights, all musical in nature. First, the music is all about timing, and the preamp and amp nailed Mozart’s complex syncopations better than I had ever heard. This is the kind of thing you might take for granted or skate over in listening to recorded music, until you hear it done exceptionally well. Second, the composition and layout of the string section were much more evident. The first and second violins were no longer blended, and I could easily recognize their section lines. These distinctions (timing and structure) result from the same phenomenon. That exquisite string-ensemble sound results from an almost uncannily precise reproduction of the time domain. At a live performance, you can easily separate out the string sections because your mind is guided by your eyes. But when listening to recorded music, the brain is deprived of visual cues. And that’s before the assemblage of resistors, wires, transformers and other bits of metal and plastic get in the way of clear and accurate reproduction. Finally, the CH Precision duo was dead quiet, allowing Mozart’s music and his expressive and rhythmic touches to emerge from the speakers with newfound power and impact. I can think of only one other time that a familiar recording was transformed so completely with a component change, and that was listening to Arturo Michelangeli’s performance of Beethoven’s Piano Concerto No.1 [Deutsche Grammophon Gesellschaft 449 757-2] for the first time on the Neodio Origine CD player. In both cases, it was like hearing a new performance. This time the experience was, if anything, even more dramatic.

And this wasn't an isolated incident. I had a similar experience listening to music played by a much larger ensemble. Bruckner’s Symphony No.4, with Claudio Abbado leading the Vienna Philharmonic [Deutsche Grammophon Gesellschaft 431 719-2], opens with a system torture test. Although captured in an ideal venue, the Musikverein in Vienna, the recording was made in 1991, the earlier, rougher years in the life of CD. The first movement’s opening starts at a whisper, a vague and barely heard string agitation, and builds slowly to a crescendo. Along the whole way, the horns and then other sections of the orchestra are surrounded by that tremolo in the strings. This is not big, audiophile-style classical music, but its subtle complexity is exceptionally hard to reproduce accurately. With the CH Precision electronics in my system, I listened to this with a principal of the San Francisco Symphony’s violin section. He had me play it over several times, finally exclaiming (with a slightly wondrous expression on his face), “That’s what I hear when I’m playing with the orchestra.” I can almost hear the cynics groan, worrying as one glowing review after another somehow makes their purchases of only a few years ago obsolete. Notwithstanding this healthy skepticism, there is little doubt when listening to electronics like these that they represent a significant advance in both performance and practicality.

Which is not to say that all change is good. Those of a certain age might recall the Acoustic Research sound demonstrations in which most listeners could not tell the difference between a live recording of a string ensemble and the same performance played back on AR 3a speakers. These days audiophiles are more likely to scoff at such a suggestion. But there’s a kernel of truth behind that now-dated ad campaign that underscores how significantly our listening habits have changed over the past three-quarters of a century -- and not only in terms of program material. Just as high-fidelity equipment has evolved from its hobbyist roots, the way we listen has progressed as well. These days it is unlikely that a curtain drawn in front of such a demonstration would fool anyone. But is that because we’ve become better at dissecting the sound of equipment and stopped listening to music?

What I am hearing that seems so remarkable from this CH Precision gear is often brushed off as mere soundstaging, a concept that some have dismissed as artifice. A soundstage, the argument goes, is not an accurate reproduction of what the recording microphones captured but an electronic restructuring of the music. No one hears such accurate placement of instruments when sitting in a concert hall, so why strive for its reproduction in a listening room? There are many things wrong with this argument, but the most significant one, and the one that most stands out when listening to how well (and how naturally) CH Precision’s preamp and amp perform, is that the soundstage is much more than the accurate arrangement of the seats on a concert stage. Getting them in the correct spot is important, because that is the fundamental basis of the pattern that underpins the performance. Where the seats are placed matters because that’s where each sound starts. Precise positioning matters, but more significant and harder to accomplish is locking in each instrument’s position temporally as well as spatially.

The best tube equipment can produce an incredibly wide and deep soundstage. CH Precision has managed to accomplish this feat without vacuum tubes. Where it has eclipsed prior efforts when it comes to reproducing the perfect soundstage is in its breathtaking success in nailing down temporal accuracy. The seemingly effortless ability to combine space and time accurately makes music sound natural and unforced, rather than artificial and reconstructed. When that happens, as it does with the L1 and A1.5, the old AR live-versus-recorded test starts to leave the world of fantasy and suggest possibilities for music reproduction we’ve only dreamed of thus far.

As I mentioned earlier, I recently heard a system, set up in a bespoke listening room and built around CH Precision’s M10 amplifiers and line stage. The effect was startling. I listened to mostly small-scale jazz, the sort of music you might think would be easily reproduced by even a more modest system. Yet it was this less complex music that clearly demonstrated the strengths of the CH Precision’s approach. The clarity of the reproduction revealed not just who was playing what, but the relationship between the instruments, the why as well as the when in the music. At the same time, that very same clarity laid bare any distortion or deviation from the natural pattern of the performance, and it underlined just how natural and undisturbed the presentation was. It brought a whole new meaning to the phrase “music in the home.”

Where does all this fit into the overall scheme of things? If the CH Precision I1 integrated amplifier gave a hint of what the gear upstream in the CH Precision line sounds like, the L1 and A1.5 are like a full menu at Arpege in Paris (11 courses) or Atelier Crenn in San Francisco (14 courses). As with when dining at these restaurants, all you need is one experience and you are left with an impression, no matter what your level of experience or sophistication, that will remain with you for a lifetime. Like the L1 and A1.5, those meals are not for (or attainable by) everyone. Unless you skimp on the wine pairing, you will be looking to drop $1000 per person at either restaurant. The L1 and A1.5 are expensive. They might be the entry point as far as CH Precision separates are concerned, but they are still genuinely aspirational components, ones that will likely require some effort and expense to hear in a showroom or system. But they are innately musical in a way that is incredibly hard to find elsewhere. Are they 10 Series beaters? Of course not. To carry the food analogy a step further, the M10 provides a world tour, embracing a seemingly endless procession of equally impressive culinary opportunities. However, the CH Precision A1.5 shares the M10’s DNA and shares its fundamental magic. While you can label the L1 and A1.5 as "entry level" in CH Precision terms, perhaps it’s more accurate to think of the pair as entry-level ultra-high-end audio, marking, as they do, a step up in musical expectation.

This preamp and amp simply make my recordings sound more like live music. Can I live without them? The review samples have departed, and the second stage of withdrawal -- plotting their return -- has begun.

Price: L1, $34,500; A1.5, $39,500.
Warranty: One year parts and labor.

CH Precision Sŕrl
ZI Le Trési 6D
CH-1028 Preverenges
Switzerland
www.ch-precision.com

Associated Equipment

Accessories: VPI MW-1 Cyclone record-cleaning machine, Record Doctor cleaning fluid and brush, VPI "magic bricks," Audio Physic cartridge demagnetizer, Shunyata Research Dark Field Elevators, Acoustical Systems SMARTractor, RPM app for fine-tuning turntable speed, Starrett No.98-6 machinist's level.

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