{"id":14439,"date":"2018-04-10T21:25:20","date_gmt":"2018-04-10T19:25:20","guid":{"rendered":"http:\/\/www.hifi-advice.com\/blog\/?p=14439"},"modified":"2023-09-26T12:58:41","modified_gmt":"2023-09-26T10:58:41","slug":"ch-precision-c1-a1-part1","status":"publish","type":"post","link":"https:\/\/www.hifi-advice.com\/blog\/review\/digital-reviews\/spdif-dac-reviews\/ch-precision-c1-a1-part1\/","title":{"rendered":"CH Precision C1 + A1"},"content":{"rendered":"

Swiss Precision at its Finest<\/h2>\n

Review samples supplied by Garmt van der Zel of Audio Ingang
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Retail Prices in the Netherlands, incl 21% VAT:<\/strong>
\nC1 DAC\/Controller – basic configuration with 1 digital input board: 26.900 euro
\nC1 – additional I\/O cards: from 1.300 euro
\nA1 Mono\/Stereo Amp: 32.100 euro per amp<\/h4>\n

Founded in 2009, CH Precision is a relatively young company but from the start, they have consistently been positioned prominently at the top of the super high-end arena. Their product catalog is extensive and their products feature in many demo systems on shows all over the world. For the longest time, American brands dominated the high-end market, but it seems that the Swiss are taking over the lead when it comes to designing truly state-of-the-art audio equipment.<\/p>\n

Designed and manufactured in Switzerland, all CH products are built immaculately. When thinking of Switzerland, the “Swiss Watches” immediately come to mind. This link is actually quite fitting as the CH enclosures are actually machined by specialized Swiss companies active in the luxury watch industry. They’re not milled from a single block of aluminum but due to the very tight tolerances and the lack of any visible screws, they almost do appear that way.<\/p>\n

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Above: inside the C1 DAC\/Controller. The four pillars are shafts for the adjustable spikes and simultaneously form the supports for other CH components that are stacked on top.<\/em><\/p>\n

Technical Background<\/strong><\/p>\n

Reviewed here are two A1 stereo\/mono amps and the C1 DAC\/Controller. All the analog audio circuitry in these components as well as all other CH components,\u00a0 is fully discrete, transistor-based, and fully symmetrical, for the shortest possible path as well as a high slew rate, high bandwidth, low noise, and low distortion.<\/p>\n

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Above: the rear panel of the A1 amp, with two input modules.<\/em><\/p>\n

Central to all CH products’ design is Modularity. The backside of each component has slots that accept a range of circuit boards. This makes it possible to fit each component only with those connections that are required for any particular purpose. Also, it allows easy swapping of boards should new techniques become available. For example, via a range of IO cards, the C1 DAC\/Controller can accept all the usual digital and analog connections as well as UPnP ethernet streaming. Adding a new protocol or allowing a new format might be a matter of simply updating the firmware but when new physical connections or internal component changes are required then it would be a matter of just swapping one of the boards, rather than sending in the entire unit for the update. This means that CH products are, to a very large extent, future-proof.<\/p>\n

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All CH products also have very cleverly integrated adjustable spiked feet. The components can be positioned just like any other audio component using their integral metal feet with elastomer rings, or one can remove the four shaft covers (machined aluminum screw caps) and insert long, sturdy spikes right through the units and adjust these from the top until the component is lifted off its regular feet and sits sturdily on the spikes. The top caps can also be exchanged for versions with a dimple into which the next component can be positioned. That way, the stacked component is not resting onto the other’s housing but is supported directly by the spikes that in turn rest on the component below it. This way, mechanical vibrations are transmitted to ground and minimized inside the device.<\/p>\n

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Ethernet Control<\/strong><\/p>\n

Uniquely, all CH Precision components can be controlled via Ethernet connection using an Android app. One might wonder why only Android and not iOS. The reason for this is simple: stability. Not that Android OS would be more stable than iOS but the latter system receives updates very frequently and these often require changes to be made to the apps that run on it. CH has opted to write code for Android only as it tends to remain compatible over the long haul, and that is what really matters: reliability. Ok, so if one opts for CH products then an Android tablet must also be calculated into the cost. So be it. Knowing the reason behind this I really cannot blame the company.<\/p>\n

The custom-made app itself is very well designed, stable and intuitive to navigate. It allows the user to operate a very wide range of settings. For the C1 DAC\/Controller, naturally, the functionality includes input selection, volume control, phase, mono\/stereo and display mode but it goes way beyond this. For example, you can also set the digital filter and clock source, adjust display brightness, dimming, and color, associate a specific display color to a particular file format, adjust gain, set mono left or right, enable\/disable\/rename inputs, set bypass mode for any input and much more.<\/p>\n

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Above and below: just a fraction of the available settings on the A1 amplifier.<\/em><\/p>\n

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The A1 amplifier also offers a large number of customizable settings. The most unusual one, but also the one that I have quickly come to regard as being indispensable is user control of the balance between local and global feedback. In 5 steps one can set the amp anywhere between 0% and 100% Global Feedback. The interaction between amp and speaker is very decisive for the end result and this in part makes that some amps are a better match for a given speaker than others. For example, speakers that are very easy to drive and have an even impedance curve will usually partner very well with amps that have little feedback. Conversely, speakers that are more difficult to drive are usually happier with the extra control offered by amps using more feedback. Naturally, I am oversimplifying things here, but because the A1 allows the user to control the amount of feedback used,\u00a0this unique function makes it possible to adjust the sound precisely as required or desired and so allows a wider range of speakers to match well than would otherwise be the case with an amp that has a fixed feedback setting.<\/p>\n

Some manufacturers believe most in measurements, others most in listening results. CH Precision could be perceived to lean slightly toward the former. They strongly believe that correctly applied technology confirmed by in-depth measurements at the lab and finally thorough listening is the way to improve the art of audio reproduction. While I often preach that measurements don’t tell the whole story and that perfect measurements are not necessarily synonymous with great sound, CH audio components effortlessly marry pristine measurements with superb sound. Also read the interview with Raphael Pasche<\/a>, one of the designers of CH Precision, in which he\u00a0answers all my questions and shares a bucketload of info about the technical principles behind CH Precision audio products.<\/p>\n

History<\/strong><\/p>\n

CH Precision is formed by a team of engineers who worked together previously as an OEM manufacturer, designing and making products for other brands. For example, they were responsible for the exceptionally well-received Anagram DSP DAC modules used in Audiomeca, Audio Aero<\/a>, and other brands. The most famous brand may well be Goldmund, for which they also designed and produced circuits. Very high slew rate and bandwidth are two of the typical aspects that Goldmund products are known for which are still present in the CH products of today.<\/p>\n

The CH Precision brand came into existence thanks to a couple of influential audio distributors. After having witnessed the team\u2019s successes they felt it was time for the gentlemen to start their own brand of high-end audio equipment. As the distribution network was already in place, the CH Precision brand was established quite quickly.<\/p>\n

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C1 DAC\/Controller<\/strong><\/p>\n

The C1 can be used as a pure DAC or as a Controller. The latter means that it also controls the volume. The C1’s hybrid analog\/digital volume control is implemented in a very clever way. Normally, when using digital volume control and a finite amount of bits it is important to stay within a certain range. This is why, with Wadia CD players and DACs, one used to be able to set the analog output level in 4 steps using internal dip switches that switched resistors into place. This way, the digital volume control could be used in its optimal range. The C1 does a similar thing but switches the various resistors into place fully automatically based on the volume level.<\/p>\n

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The supplied IR remote controls power, input selection, and volume level. The app provides an even better way to control this. Especially the volume control is built very cleverly and implemented in such a way that one can never accidentally set the volume to 100% in one move, but still allows very good control. By the way, software volume control is disabled for third-party apps to prevent sudden volume leaps.<\/p>\n

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Arguably the most important part of the C1 is its DAC section. It uses what is referred to as a linearized R-2R, using four PCM1704 IC’s per channel, working at 24 bit \/ 705.6kHz & 768kHz. Depending on the input, the C1 accepts max 24 bit 192kHz via AES\/EBU and SPDIF, max 32\/384kHz and DSD 1 bit \/ 2.8224MHz (DSD64) & 5.6448MHz (DSD128), DoP mode only, via USB and max 32\/384kHz and DSD 1 bit \/ 2.8224MHz (DSD64), 5.6448MHz (DSD128) & 11.2896MHz (DSD256) via Ethernet.<\/p>\n

linearized R-2R as explained by CH on the website<\/strong><\/p>\n

“The digital signal processing chain in the C1 is complemented by a proprietary signal conditioning stage which optimizes the signal for conversion by numerous R-2R converters per channel. Because each converter has a slightly different gain and offset, an automated calibration system harmonizes their operation. In addition, in order to address low-level linearity issues inherent to R-2R converters, unique scrambling technology is applied. By sending slightly different signals to each converter through the addition of an algorithmically generated, low-level, random high-frequency noise (which is canceled out in the analog domain), the low-level linearity is significantly improved.”<\/em><\/p>\n

The DAC also takes DSD which is decoded into PCM prior to conversion. The DAC does upsample but only in a synchronous manner, meaning that any input rate is multiplied in integer amounts, for example, 2x, 4x, 8x, or 16x, depending on the input frequency, rather than simply upsampling to a fixed asynchronous frequency. This is an important aspect that I first learned about when playing with the dCS Delius DAC and Purcell upsampler. The latter sounded markedly better when switched to an output frequency that was a whole multiple. For instance, CD’s 44.1 kHz sounded great at 88.2 or 176.4 upsampling but sounded softened on the transients when set to 192kHz. DSD is converted to PCM. While some might see this as being less puristic I should point out that the best DSD players I heard included a Wadia 781i<\/a> which does the same thing.<\/p>\n

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C1 in DAC mode<\/strong><\/p>\n

When using the C1 together with a preamp it is important either to set it to DAC mode or to set the input’s volume control to Bypass, to yield the tightest and most articulate sound. There is no difference that I could perceive between these two methods but it is important to note that either mode sounds more articulate than simply leaving the C1 in Controller mode and setting the volume level to 100.<\/p>\n

Just as with any other DAC that I used, the C1’s inputs sound slightly different. AES\/EBU sounds fuller and a little warmer while cinch coax sounds tighter and more direct. However, it is important to point out that these differences could also be induced by the cables or the source outputs. In any event, the choice between the inputs comes down to taste, and availability, not to absolute quality.<\/p>\n

C1 Filters<\/strong><\/p>\n

The C1 offers three filter settings: Minimum Phase (labeled Minimal phase in the menu), Linear phase (Apodising), and Linear phase (Sharp). The DAC was delivered set to Minimum Phase mode and when experimenting with this I quickly established a preference for this setting too.<\/p>\n

The C1 with the Minimum Phase filter sounds slightly dark in comparison to most other DACs, Wadias excluded. The Aqua Formula xHD<\/a> DAC, for example, sounds more energetic in the treble and by comparison more open. It doesn’t actually present more detail but probably because it has no filters and has a very uncolored presentation, it just sounds a bit more open, but also less sonorous further down.<\/p>\n

Switching the C1 from Minimum Phase to\u00a0Linear Phase (Apodising), the C1 becomes noticeably brighter and more open on top. But for my taste it is no improvement, actually making instruments sound less like real instruments. The Minimum Phase filter may result in a darker sound, but it is definitely also acoustically more real, with textures that are better fleshed out and more convincing. Instruments are more 3D, with more body, and the whole delivery, in general, is more free-flowing.<\/p>\n

Linear phase (sharp), finally, sounds nicely neutral frequency-range-wise, but somehow makes the music sound a little flat and uninspiring, more so than Linear phase (apodizing). Needless to say, I continued to use the C1 in Minimum Phase mode for the remainder of the review.<\/p>\n

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Listening – Martin Logan Renaissance ESL 15A<\/strong><\/p>\n

To start off, the C1 was used as a DAC and preamp straight to the two A1 amps (in monaural mode) using CH “Precision Balanced” Link XLR interlinks en Jorma No.3 speaker cable. The main digital source for all listening is the Ayon CD-T II<\/a> transport connected via AES\/EBU and coaxial, alternating between the two.<\/p>\n

It has to be said: these CH components match phenomenally well with the big Logans! With the feedback set anywhere between 0 and 40, they sound great but I tend to 20 as the best value for the Logans. A value of 0 makes for beautiful mids but overall, with the Logans which are themselves relaxed, this can make the sound a little too relaxed.<\/p>\n

Martin Logans have very many great attributes, some of which are very difficult to obtain with dynamic speakers. One of their downsides I find however is that they can sound timbrally less convincing, a little synthetic if you will, unless matched with a particularly natural-sounding amp. In the recent past, I’ve found AVM amps (both their entry-level equipment as well as their high-end offerings) to work very well in this regard, much better in fact than the Jeff Rowland model 6<\/a> power amps that I have used for so long.\u00a0 The CH Precision amps however also excel in this regard! This setup sounds timbrally wholly credible yet superbly neutral from top to bottom and with a transparency that is simply unbelievable. Resolution is first-rate and treble is nicely fluid and airy, and in spite of there not being an analog preamp, there is no dryness whatsoever.<\/p>\n

From the very first seconds of listening,\u00a0it was immediately clear that these components have very low distortion, incredible transparency, and superb detail retrieval. Regular readers will know how I have often praised the model 6 power amps for being so highly refined. For the longest time, their level of nuance and fine detail had been unequaled by other amps and when other amps did have similar resolution, inevitably they were less proficient in other parameters.<\/p>\n

The CH Precision A1 amps not only offer a similar fluidity and refinement as the model sixes did, they actually improve on them in all other parameters. While the sixes excelled in the aforementioned aspects, they were never state of the art in terms of dynamics, bass power, or timbre and texture. Brystons<\/a>\u00a0sounds bigger and beefier, Pass Labs amps have purer\u00a0midrange and more natural timbre and, although the sixes are very stable, it is not difficult to find an amp that sounds<\/em> more powerful. The incredibly affordable\u00a0NuPrime ST10<\/a>, for example, has\u00a0more impressive drive and dynamics as well as more natural timbre than the sixes, but as would be expected, it does not provide a Jeff Rowland level of resolution and refinement. To cut a long story short: it is difficult to find an amp that does everything equally well.<\/p>\n

The A1’s however, do, and then some! It sounds incredible, but it seems that these components simply seem to give it all. They tick each and every one of the audiophile boxes but they also make beautiful, soul-stirring music in a decidedly non-technical manner.<\/p>\n

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Back to the C1<\/strong><\/p>\n

Back on the subject of the C1 DAC\/Controller, I’ve always been a fan of Wadia DACs, especially because of their superb bass performance and their excellent midrange texture. Their lesser aspects include a dark tonality and less than fluid treble. These aspects became better and better as the brand released new models and the 521 DAC<\/a> really was a very good compromise between the brand’s classic strengths and a more refined, more modern sound. Since I can’t very well keep comparing review components to classic components that are no longer available I have been searching for alternatives, only to find that none had the Wadia strengths to the same extent as Wadia did. Nevertheless, aspects that could be improved upon quite easily were low-level detail, bass tightness, and overall resolution. My current reference DACs include the 10.000 euro\u00a0Bricasti M1<\/a> (for a smoother, forgiving sound) and the Aqua Formula xHD<\/a> (for the best transparency and a more neutral delivery). Both DACs are higher resolving and airier than the Wadia was and although the Aqua also betters the 521 in terms of midrange purity and natural tonality, it does not quite have the Wadia’s bass heft or its big and sonorous presentation. These particular Wadia traits could well be regarded as\u00a0coloration, especially when compared to the aforementioned DACs.<\/p>\n

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Comparing the C1 with the Aqua is not really fair as the C1 is 2,5 times as expensive but still I think it offers interesting insights because the Aqua is likely familiar to more people than the CH C1 and as such provides a good reference point. Also, the Aqua is actually the best DAC that I have heard to date.<\/p>\n

But, as always happens sooner or later, in comes another component that upsets the status quo and offsets my beliefs. Of course, I am talking about the CH Precision C1.<\/p>\n

The CH C1 sounds fuller, more sonorous, and more relaxed, and with wider soundstaging, the Aqua sounds more agile and more open on top and has a more concentrated, more focused soundstage. Both DACs sound highly detailed, rhythmically engaging, dynamic, and timbrally very convincing. In spite of their different characters, both come across as being very neutral and uncolored. And yet the CH C1 keeps fascinating me and luring me in with its remarkable combination of qualities. This really is a very special DAC: relaxed and sonorous and not “forward” in any way yet highly dynamic and always “just right”.<\/p>\n

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The Bricasti M1 is a very refined DAC with a gloriously rich, liquid and lush midrange, quite untypical for DACs. It does not sound “digital” in the classic sense in any way. Not without reason was the M1 my reference before the Aqua came along to replace the M1 as my new favorite DAC. Just as the Aqua highlighted the softness induced by the Bricasti, so does the CH Precision C1. What’s more, compared to the C1, the M1 sounds quite threadbare, in spite of its liquidity. And this is the weird thing because the C1 has all the liquidity and smoothness that you could ask for yet none of the Bricasti’s blur.<\/p>\n

This is just the thing with these CH components: upon first hearing, it is easy to conclude that they perform flawlessly but apparently not special, because they are so un-hyped in their presentation. But as soon as you switch back to earlier references it becomes painfully clear how deviating and colored other components can sound.<\/p>\n

The C1 has the sublimely solid and powerful classic Wadia type of bass and a similarly energetic yet acoustically wholly convincing midrange tonality but combined with a Bricasti-like organic fluidity, smoothness and treble refinement and an overall articulation and low-level resolution that equals that of the Aqua Formula xHD. The C1 offers all this, yet it does not sound dry or analytical in the least. Wait, what? I can have my cake AND eat it? Apparently so!<\/p>\n

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Cables<\/strong><\/p>\n

As power cables to the A1 amps, I used Belden 19364<\/a> with Oyaide 004 connectors. These are pretty standard cables but they do not alter the sound and as such are dependable neutral products. Because the A1 amps sounded so utterly fantastic from the start, I did not carry out further experiments. I’m sure that the amps can be further tweaked to sound fuller, or more articulate, with certain cables but in my setup at least, I just don’t think that they require this.<\/p>\n

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The power cable to the C1 DAC\/Controller was a Furutech Alpha 3 with Furutech 038 connectors. This is a cable that adds some fullness and color to the sound but since I use the same type of cable on the other DACs I thought it only fair to not change the recipe for the C1. In use, I found this to be a great combination but then admittedly all speakers I used sound very open. I can imagine that darker-sounding setups might benefit from using a more neutral cable with the C1.<\/p>\n

I tried 3 types of interlinks between the C1 and the A1 amps, all balanced XLR. First was the CH Precision “Balanced Link”, made by CH in close collaboration with Argento Audio. This cable is made to be an ideal match with CH components, having extremely low capacitance to provide an extra high bandwidth connection. These cables sounded great from the start but still, I felt I had to do some experimenting in order to really be able to identify the cables.<\/p>\n

First\u00a0up for comparison was the 700 euro\u00a0Black Rhodium Concerto<\/a>. Natural, transparent and smooth, these cables had already proven to be great in another system context. Now were the CH cables so very good, was it the system’s overall resolution or was it just a mismatch? Maybe it was a bit of all but in any event, the Black Rhodium cables provided very good neutrality but a much-diminished presence. Compared to the CH cables, the transients were blurry and transparency reduced. It’s easy to assume, certainly not always the case, but apparently, this setup deserves higher-end cables.<\/p>\n

Then I tried Cardas Clear<\/a>. This was a different story. Smooth like the Black Rhodium and indeed rounder and more fluid than the CH cables but still nicely dynamic and still highly transparent. The transients are certainly not quite as immediate as with the CH cable, but this is definitely a very nice presentation, too, and more a matter of taste than of absolute quality. The Clears in effect add a little “Rowland” smoothness to the sound but without reducing the tempo, which can be very welcome for example when speakers sound a little forward or if one just prefers to “mellow” the sound a little.<\/p>\n

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Although I quite liked the Cardas Clear interlinks for their easy-going sound, ultimately I found that the CH cables made the most of the CH components by making them sound the least processed, and most “live”, without adding any unnatural zip and most definitely not adding any harshness. They are just a very good fit, leaving nothing to be desired. Cable choice is a relative matter, however, and my preference might not be yours, so experimentation is always encouraged.<\/p>\n

Moving On<\/strong><\/p>\n

So far I’ve been listening to the three CH components using the Martin Logan Renaissance ESL 15A’s but I will also be using Wilson Audio Watt\/Puppy 8’s as well as Apogee Duetta Signatures<\/a>. You can read all about this in part 2 of this review, but first I will write about the influence of adding an analog preamp to the system.<\/p>\n

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Swiss Precision at its Finest<\/h2>\n

Analog preamp not required<\/strong><\/p>\n

The CH components, especially the power amps, have an almost unassuming delivery: they don’t brag or try to impress the listener, in essence, they do not subtract or add anything. They do not add any extra “attack” or “slam”, so depending on the music that is played, they can appear to be a bit unspectacular. But meanwhile, they are so articulate, pure, transparent, dynamic and immediate, that it was a bit of a let-down when I switched the Jeff Rowland Corus<\/a> preamp (+PSU) into the system, leaving the C1 to perform DAC-only duties. The Corus is an extremely refined preamp and so far it has never performed less than fantastic but compared to the C1 in Controller mode directly to the power amps, the resulting sound comes across as being comparatively rounded and mellow. The interesting thing is that cutting out the preamp during past efforts also usually resulted in a more clearly defined bass and a purer, more direct sound, but always at the cost of soundstage size, smoothness or overall sense of power. With Wadias in particular, the bass and dynamics are usually best without a preamp but this always comes at the expense of a dry and square-ish treble. There’s none of this however with the CH Precision C1. This DAC sounds utterly fluid, airy, refined, powerful and yet colorful and sonorous, and even when it drives the power amps directly.<\/p>\n

Versus Aqua Formula xHD DAC<\/strong><\/p>\n

With the Corus preamp still in place, I switched from the CH Precision C1 to the 13.670 euro\u00a0Aqua Formula xHD<\/a> DAC using the same digital connection. It has to be said: in this context, with Corus and the Martin Logans, both not the world’s most dynamic-sounding components, the Aqua’s comparatively more spritely presentation made for an arguably more synergetic match. This just goes to show how relative audio matters are. It also indicates just how great the Aqua DAC is. It does not have the C1’s timbral fullness and wide soundstaging or its overall sense of power, but it is highly involving and\u00a0very communicative.\u00a0Leave out the Corus though, and the combined C1+A1 presentation is again indisputably elevated several notches above Aqua + Corus. This nicely shows that inter-component matching and overall system synergy is ultimately one of the most important aspects of all.<\/p>\n

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Listening – Wilson Watt\/Puppy 8<\/strong><\/p>\n

After the superb results using the CH equipment with the Logans, it was now time to see how they performed with the Wilsons. Before going full out though, first I switched back to the very cost-effective 3375 euro\u00a0PrimaLuna DiaLogue Premium<\/a>\u00a0tube amp that has been functioning as my default go-to amp while I am making up my mind as to which amp works best with the Wilsons.<\/p>\n

As could be expected, the humble PrimaLuna DiaLogue Premium<\/a> with KT150s<\/a> could not keep up with the A1’s, especially in terms of refinement, resolution, evenness, and transparency but it still turned in a lively and enjoyable presentation, once you have gotten used to its rougher presentation. This is the remarkable thing with tubes: even if they don’t perform anywhere near as well on the usual audiophile individual aspects,\u00a0still, they can possess a certain magic and engagement factor. Then again, if one wants a tube amp to approach the A1’s incredible levels of neutrality, transparency, and refinement then considerable funds are required just the same.<\/p>\n

Naturally, it first took some acclimatizing to switch from the transparent and refined Logans to inevitably more colored “cabinet” speakers. Indeed the first evening when switching I could not get comfortable with the Wilsons quite so easily. As open and neutral as the Wilsons seem, they still sound quite uneven compared with the Logans. By comparison, the Wilsons’ frequency range seems to go all over the place.<\/p>\n

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Above: the PrimaLuna amp normally sits on an Artesania platform<\/a> with the NuPrime ST-10 below it. To level the circumstances with the A1’s, I placed it right on the floor for this comparison.<\/em><\/p>\n

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However, when switching from the PrimaLuna to the CH Precision A1 amps,\u00a0much of that unevenness was greatly reduced, not only in the bass, which was now tighter, deeper and more articulate but also in the midrange and treble which became more polished and more well-mannered. So, while the Wilsons are no Logans in terms of evenness, understandably, the PrimaLuna also is no CH.<\/p>\n

After some time though, my sensibility to this aspect yielded to the lure of the Wilsons’ more expressive and dynamic sound and the next day I was no longer bothered by it at all. To me, this indicates that our hearing and the way that we listen to music is much more sensitive to shifts in loudness than unevenness in the frequency range. Once I was used to the Wilsons, it occurred to me that this was actually the best bass that I had heard them produce so far! Tight, deep, articulate yet sonorous and bold, it was just right! It has to be said: just like the Logans, the Wilsons also showed a remarkable synergy with these CH components.<\/p>\n

A1 Operating Modes<\/strong><\/p>\n

The A1 amp can be switched in various operation modes: Bridged Mono Mode, Left or Right Mono Mode and Passive Bi-Amp Mode. When adding a second input board (as was the case with the review samples), the A1 provides the following additional modes: Stereo Mode and Active Bi-Amp Mode. I won’t go into detail on all these modes but will describe the two modes that I used.<\/p>\n

Stereo Mode<\/strong><\/p>\n

In Stereo Mode the amp works as a traditional stereo amp, each output stage being driven by its dedicated input board.<\/p>\n

Left or Right Mono Mode<\/strong><\/p>\n

In Mono Mode, the entire power of the transformer is available to a single output channel. Don’t confuse this with Bridge mode which uses both channels either in parallel or in series. Instead, the Mono mode disables one input board and makes it possible for this 100-watt amp to actually deliver 550 watts under 1 ohm and this makes it ideal for driving low impedance speakers.<\/p>\n

A1 Mode Listening Results<\/strong><\/p>\n

To start off, I used both A1’s in Mono Mode with the inefficient\u00a0Apogee Duetta Signature<\/a> magnetostatics, and this worked like a charm. In fact, I don’t think that I have heard them perform more magically than this. And the bass! Boy, was it ever so well-controlled yet super-nimble!<\/p>\n

The Martin Logans also blossomed using this mode, even if they do not actually require much current at all. This is more a matter of preference and matching than of electrical requirements, but I just preferred how the Mono Mode made the Logans sound slightly more sonorous than the Stereo Mode. I’m sure that a single A1 would have driven the Logans splendidly too, but alas, I did not think of trying this.<\/p>\n

The Wilsons may have funky impedance curves but they really are not very power hungry and they work very well with all the tube amps that I tried, such as the aforementioned PrimaLuna but also the Audio Research Ref75SE<\/a> and the Vaic Reference 520’s<\/a>. This being the case, a single CH Precision A1 amp should definitely have more than enough power to drive the Wilsons perfectly. Swapping back and forth between a single and dual A1’s proved that indeed a single A1 sounded every bit as powerful and in control as two A1’s.<\/p>\n

The thing is though, using two A1’s in Stereo Mode, each powering one Wilson speaker, does bring other benefits. Compared to using a single amp in stereo mode, using two amps, still in stereo mode, with the same power cables and interlinks, provided an even more delicate sound that was seemingly<\/em> more extended at the frequency extremes. I don’t think that this was actually the case, but evidently, the separation of the two channels does have a certain effect, one that goes beyond supplying double power.<\/p>\n

When using two A1’s with the Wilsons, I found that both Mono Mode and Stereo Mode worked well, but the latter produced the more expansive soundstage with a more agile, airy and free-flowing feel. This is not a day and night difference, but it is not difficult to hear either.<\/p>\n

\"\"<\/p>\n

Above: display on temperature mode, below: display on power mode.<\/em><\/p>\n

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With or without Corus preamp<\/strong><\/p>\n

After the Logans’ smooth presentation there was still some lingering hankering for some extra fluidity and so I switched in the Corus again. And indeed this brought a welcome sense of liquidity and smoothness. While certainly attractive and still very much high-res, not masking any details, the Corus did, however, impose a mild softness on the sound and after some time, I started longing for the purer C1-direct sound. After switching the Corus out again and setting the C1 back to “Controller” mode, there was no more doubt on my mind. Just as with the Logans, the sound was best when using the C1 directly connected to the A1 power amps.<\/p>\n

With the Wilsons, too, I much preferred the CH Precision interlinks. It seems that these cables provide the liveliest sound but without adding any character of their own, which I really find quite remarkable!<\/p>\n

Analog Domain M75P<\/strong><\/p>\n

On the surface, the A1’s sound similar to the 19.600 euro\u00a0Analog Domain M75P<\/a>. Both amps sound exceedingly neutral, uncolored and transparent and both have superbly natural timbre. However, while the Analog Domain sacrificed some liquidity and refinement compared to the Rowland model sixes, the CH A1 fully retains these qualities. There’s all the neutrality and dynamic capability that one could desire, but also superb resolution, midrange liquidity,\u00a0and treble air. To put this into context: a single A1 costs a whopping 10.000 more than the Analog Domain amp, and I am actually comparing two A1’s with a single M75P. So, this is not really a fair comparison but it does go to show that there are indeed ever better results to be obtained with transistor amplifiers if one is prepared to spend more.<\/p>\n

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Soulution 711<\/strong><\/p>\n

Speaking of spending more, audio buddy Niels was so kind as to bring along his Soulution 711. At 55.000 euro it is the most expensive amp that I have listened to in my system so far. Just as with CH Precision, it seems that many people are under the impression that Soulution amps sound cold and sterile. Reading older reviews it seems that indeed earlier Soulution products may have actually tended in that direction. But I can confirm that the 711 sounds full-bodied, sonorous and even warm, not bright or clinical in the least.<\/p>\n

Like the CH Precision amps, the Soulution 711 uses a smart system to monitor and maintain proper\u00a0transistor bias in all circumstances and while it does not offer the convenience of adjusting the feedback on the fly, it only employs local feedback, no global feedback. So, when setting the A1’s to zero global feedback, these two amps operate more or less on equal ground.<\/p>\n

In the Analog Domain review<\/a>,\u00a0I used the 711 with the Apogee Duetta Signature, Vivid Giya G3 s2, and the Wilsons. For the purpose of this review, however, I will only use the Wilsons.<\/p>\n

When switching from the A1’s to the 711, the latter sounds fuller in the midrange, more sonorous in the bass and darker overall.\u00a0 It’s actually somewhat similar to the overall PrimaLuna sound, as weird as that may sound. Of course, the 711 beats that amp on all accounts except the typical lyrical aspect so typical of tubes but they share a similar presentation in terms of tonality and especially in the midrange, which with the 711 could even be argued to be somewhat tubelike. The 711 also comes across as being more dynamic when playing material that is not itself very dynamic but this might just be a matter of added heft.<\/p>\n

It’s certainly a tempting sound and if one’s aim is to find a transistor amp that actually performs like a tube amp on steroids then this is it. However, compared to the CH amps, the 711 does come across as being slightly congested and colored. It is not as transparent and airy, or as agile as the A1’s. To my ears, the 711 is more romantic and certainly easy to listen to but the A1’s have a purer and more honest presentation. Ultimately, these are quite different amps catering to different tastes.<\/p>\n

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A1 Adjustable Feedback<\/strong><\/p>\n

As explained in part 1 of this review, the A1 offers user control of the balance between local and global feedback. In 5 steps one can set the amp anywhere between 0% and 100% Global Feedback. This can be set on the amp itself or via the Android App.<\/p>\n

For the Logans, zero global feedback made the overall sound just a bit too relaxed but I obtained great results with a setting of 20 or 40, ultimately preferring 20 as the best balance between immediacy and smoothness.<\/p>\n

This turns out differently with the Wilsons, which are quite punchy and lively themselves and so make the nicest match with the feedback set to zero. With the Wilsons, this results in a nice relaxed sound, with organic and free-flowing mids, again reminiscent of typical tube sound. Of course, the bass also becomes less forceful but because these speakers have bass-punch built in this is not an issue. Also, the A1’s have such incredibly good bass even at zero global feedback that the end result is still better than with most other amps.<\/p>\n

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Apogees are known to love power and control, and one would expect the Duetta Signatures to perform better with more feedback but actually, it turned out that the A1’s have such splendid control over the speaker that it was not necessary to raise the setting. Sure, the sound became even tighter with a setting of 20 or 40, but not subjectively better. Left on zero, but with the amps set to Left or Right Mono Mode, the Duettas already sounded like they had the oft-quoted “Iron Fist” control while having gloriously smooth and free-flowing mids and treble.<\/p>\n

I think this also speaks of my personal preference, and apparently, I like the sound of little or no global feedback, provided that the amp-speaker match is such that the bass is still tight and articulate. I find that raising the level of Global feedback, in general, can lead to more control and a tighter sound, but it can also reduce the sense of dynamics and flow. I guess this is why I am currently also quite fond of using tube amplification with the Wilsons. The thing is: oftentimes I am forced to choose between “Magical Midrange” and “Seismic bass”, but when using multiple A1’s, you are actually able to set a different feedback setting for the bass than for the midrange and treble. This way, one could set the bass channel to 20, 40 or even 60%, while leaving the midrange\/treble channel on zero. That way, one could potentially get the best of both worlds!<\/p>\n

Streaming via the CH App<\/strong><\/p>\n

The CH App has tabs for all connected CH components and in case of the C1, when the optional UPnP board is installed, there is extra functionality that allows full use of the usual UPnP streaming options. The advantage is that these are embedded into the same app that controls all the other CH functions, which makes it super-comfortable to cue and play tracks while adjusting volume and changing other settings. The status tab shows all the C1’s normal statuses but also cover art, artist name, album name, genre and file attributes. There’s also a scrubbing bar that allows fast-forwarding or rewinding within a track and people with UPnP experience will know that this particular functionality is often missing.<\/p>\n

The basic functionalities for browsing are dependent on what the UPnP app on the NAS offers but usually include browsing by Artist, Album, Genre, Recent additions, Years and Folder View, which enables browsing the folders with the physical structure as it exists on the NAS.<\/p>\n

I’ve been spoiled by Roon and iPeng, which both offer very extensive functionality and compared to these apps, the CH app looks very basic, but for the majority of users, it offers precisely enough. From the Libary View, you can choose between play now or Queue entire albums, individual tracks, or track selections.<\/p>\n

There are some functionalities that I do miss. Items can only be queued at the end of the Queue, not for example after the currently playing track. Also, it is not possible to change the order of items in the queue or in playlists. In fact, there is no playlist editing outside of being able to add items to existing playlists, overwrite them or to create new ones.<\/p>\n

Music Server Matters<\/strong><\/p>\n

For starters, I ran some tests using the AudioAanZee Reference Flow<\/a> Music Server. Based on a VortexBox install, it also includes Logitech Media Server, which works without having to make any settings. Just browsing the source options on the Library page, where all UPnP-compatible servers automatically show up, it is a matter of selecting the server of choice and you’re done.<\/p>\n

Because all UPnP methods rely on a control point (the tablet) accessing indexed library data from a server, response times really depend on the speed of the server that is used. Roon and iPeng (both not UPnP applications) overcome this by caching the data on the tablet but this does not seem to be the case here, nor am I aware of another UPnP app that does. When using the LMS server on the Reference Flow. which is not really designed to be operated like this, there is indeed a short delay every time you want to navigate to another folder and when navigating directories containing many files the files get loaded in batches, preventing continuous scrolling. After having loaded once, however, it is possible to scroll even large directories continuously, so it seems that the data is temporarily held in a cache.<\/p>\n

Garmt\u00a0also brought along a Melco N1A\/2 music server, saying that it would make a marked difference and in his opinion actually is the best way to use the C1. This server uses Minim Server as the UPnP library and connects via a direct and clean Ethernet connection and is a lot faster, and I mean A LOT faster. Using the Melco there is still the tiniest delay when browsing folders but it is so very quick that it does not bother me at all.<\/p>\n

Most important of all, what completely seals the deal here is the sound quality when using the C1’s UPnP Streaming input.<\/p>\n

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Streaming Sound Quality – LMS<\/strong><\/p>\n

When using LMS on the AudioAanZee server to stream to the C1 via UPnP, the music sounds more energetic and lively, in fact, more “live” than using either the Reference Flow’s USB output into the Bricasti or Aqua DACs or the Bryston BDP-3 streamer in Roon Ready mode via AES\/EBU or coax on cinch directly into the C1. With the C1’s streaming mode using the AAZ server, the sound was simply tighter and dynamically more pronounced, and actually, more live<\/em>. The other options, by comparison, sounded a little rounded-off and although the difference is seemingly small in a quick A-B comparison, it makes a lot of difference for the music’s entertainment value. Somehow, the other sources just sound less interesting.<\/p>\n

\"\"<\/p>\n

Compared to the very articulate and lively\u00a0Ayon CD-T II<\/a> transport (used in PCM mode), streaming mode sounds just as refined but is slightly less agile, less articulate and less dynamic. Transients just seem more immediate and more powerful from CD.<\/p>\n

\"\"<\/p>\n

Streaming Sound Quality – Melco<\/strong><\/p>\n

When switching to streaming from the Melco N1A\/2 server, however, the sound was even more impressive. I was already hugely impressed but hearing the C1 together with the Melco renders me even further impressed! All the aforementioned advantages of using streaming remain, but now with even better low-level resolution, more calmness (less “hash” I suppose) whilst at the same time sounding quick, articulate, energetic and very dynamic. The CD source is still a little drier but I’m not so sure anymore if that is the better performance as it also sounds soberer and therefore arguably sometimes less involving.<\/p>\n

In any event, these sources are so very close to each other that I can’t even always tell the difference. This may sound like something that goes without saying (bits are bits) but trust me, this really should not be taken for granted. It is actually not at all easy for a computer and an endpoint to accomplish such transparency, as evidenced by the less spectacular results using the other server and endpoint.<\/p>\n

\"\"<\/p>\n

Garmt also brought along an AudioQuest Vodka ethernet cable. As a final experiment, I compared this high-end cable (from 275 euro for 0,75m) with a standard 7 euro ethernet cable. I know I am going to get complaints because many people feel that it should not be possible but yes indeed, I can hear differences between these cables. However, not as expected perhaps because, as it turned out, I preferred the standard cable. The AudioQuest cable provided a smoother, more introspective sound than the standard cable. I could see this more relaxed sound being preferred in some situations but although it was supremely refined and the dynamics were intact, compared to the CD transport, the transients were definitely less immediate and this made me feel like the music was somehow processed<\/em>. Your mileage may vary so, as always, just experimenting with this is the best method of finding the ideal combination for any given situation. Also see the separate Melco review<\/a>, in which I compared a couple of Ethernet cables.<\/p>\n

As this review is coming to its end, the most prominent thought on my mind, even when I’m writing this in the adjacent room, is that I am continuously overwhelmed with the feeling that the C1 combined with the two A1’s and streaming via Melco simply sounds truer to life than any other digital source that I have ever used. And that is really saying a lot!<\/p>\n

Conclusion<\/h2>\n

I’ve heard people state that CH Precision products sound cool and clinical, but this is absolutely not how I hear it. The C1+A1 combination sounds ultra-transparent, clean and controlled clean but also smooth and fluid, and organic. CH components deliver a truly lifelike sound that is not about added warmth, ultra-impact or tube magic. It is simple to claim that nothing is added and nothing is subtracted but this is actually what seems to be happening here. However, it is not a system that delivers the truth at the expense of musicality. Sure, play mediocre recordings and they will sound mediocre, but you can literally play any kind of music on this system, and it plays everything without prejudice and without ever adding even a hint of hardness.<\/p>\n

Some audio components excel in their ability to allow the listener to dissect the music into its every musical strand, for example to precisely follow a certain subtle rhythmic aspect or almost hidden melody line. Often though, such super-transparent components can make for a more technical delivery, reducing the emotional impact in the process. Other audio components excel in luring one into the emotional performance and making one forget about the technical aspects altogether. These components, however, can tend to “generalize” the subtle elements of which the music is made. This discrepancy is something that I have often proclaimed to be inevitable because like humans, no audio component is perfect.<\/p>\n

CH Precision audio components tick all the audiophile boxes, there need be no concern about that. however, they are unique in my experience for possessing the finest technical abilities while totally making one forget about them by simply sounding utterly realistic, wholly musical, and absolutely convincing. The various technical aspects are woven together so utterly seamlessly that one is encouraged to stop the eternal analysis and simply enjoy the musical performances. It’s as close as I have heard audio components come to perfection.<\/p>\n

\"\"
\n(CH Precision C1)<\/p>\n

\"\"
\n(CH Precision C1.2<\/a>)<\/p>\n

\"\"
\n(CH Precision C1.2<\/a>)<\/p>\n

 <\/p>\n

Associated Equipment<\/a><\/p>\n

Videos on the Hifi-Advice YouTube Channel<\/h3>\n

How Sooloos became Roon<\/a>
\nHFA Front Page<\/a><\/p>\n

Read Also<\/h3>\n

Melco NA1\/2 and N1ZH\/2 compared<\/a>
\nAn Interview with Raphael Pasche of CH Precision<\/a>
\nCH Precision A1.5<\/a>
\nCH Precision A1.5 compared to Soulution 711<\/a>
\nCH Precision L1<\/a>
\nCH Precision P1<\/a><\/p>\n

External Links<\/h3>\n

Manufacturer: CH Precision
\n<\/a>Distributor for the Benelux: Audio Ingang<\/a><\/p>\n

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