But while such thinking and system topologies are not exactly news in the realm of analog audio equipment, with very, very few exceptions (CH Precision again, Naim Audio and the French Total DAC), they’ve yet to penetrate digital thinking and hardware. Yet, if anything, the benefits of enhanced and dedicated power supplies should be even greater in the digital domain, with its complex, high-frequency noise issues and the split personality of its digital and analog circuit requirements.

But in the case of the CH Precision digital replay chain, we can take things several stages further than that, with a system topology that can stretch from one box to nine and an array of options that include anything from separating the transport and DAC, to dedicated, dual-mono DAC channels, an external master clock and, of course, external power supplies for everything in sight. It’s a unique opportunity to examine the relative importance of different elements within the system, and whilst the findings are specific to this product line, they can also be generalized to other digital systems, even if those systems don’t allow separation of the various functional blocks.

Of course, any such undertaking is a far-from-straightforward exercise. You’ve got to accommodate all those boxes and hook them all up -- all without compromising the support or cables used for any one box relative to the others. That means a lot of identical shelves, couplers, cabling and a lot of attention paid to both power supply arrangements and grounding. It also involves a lot of comparative listening, level matching and system resets as the topology and connectivity change. Just trying to keep a track of the practical demands is hard enough -- and that’s before you try to conduct any sort of listening.

So with that in mind I decided on two courses to maintain my sanity: one was the decision to stick to the seven-box rig rather than the full nine; the other was confining myself to two discs for the entire process, the albums chosen being: Sibelius Violin Concerto, Baiba Skride, Santtu-Matias Rouvali and the Tampere Philharmonic Orchestra [Orfeo CD C 896 152 A], and The Pixies: Doolittle [Elektra/Mobile Fidelity UDSACD 2033]. Between the two of them, they serve up classical and rock, CD and SACD, solo instruments, voice(s), a great rock recording and orchestral passages, which cover most musical demands. Okay, so there’s no jazz in there, but that was included in the peripheral listening and Sibelius sure did love his brass.

I began by listening to the D1 CD/SACD player as a standalone solution, (which starts at $38,000 with a single set of digital outputs, but which will set you back $44,500 if fully loaded with analog outputs and a clock Sync I/O board), although these days I suspect that many audiophiles will jump straight to a DAC, dispensing with disc replay in favor of streaming music. I included the D1 for completeness, because it’s a darned fine transport and because it provides a more stable source for this kind of exercise than any streamer. However, past experience indicates that as a single-box solution, it’s far from ideal. Its presentation is as solid and stable as its construction, but it is also limited in terms of tonal color, rhythmic flexibility and expressive range, altogether too prosaic and matter-of-fact for my tastes. Some will applaud its unflustered sense of control and even-handed absence of exaggeration, linearity that keeps the musical range perfectly flat and free of undue emphasis, at either extreme or in the middle -- aberrations adopted by many a player to add spice to its presentation. However, these same qualities go a long way toward qualifying it as a transport (as opposed to a player), and given that the CH Precision range includes both the DAC-equipped I1 and the various C1 options, it’s hard to escape the conclusion that this is its natural role. By offering the option (and as with most things CH, it is an option) of an internal DAC, the company creates a standalone product, a stepping stone to bigger things and a backup plan in case your main DAC goes down -- all of which makes sense. But ultimately, this is neither the best-sounding nor the most affordable one-box player out there. What it is is the first brick in what could become a substantial wall.

As suggested above, the D1 comes into its own once you pair it with one of CH Precision’s external DACs, be that the C1 (starting at $32,000) or the internal DAC in the I1 integrated. Both units allow you to employ the company’s excellent, proprietary CH-Link HD wide-bandwidth digital interface, which is capable of native DSD transfer (hence my inclusion of SACD in the listening). They also allow you to configure the clock syncing between them via a BNC lead, designating the DAC as the master clock to considerable musical effect. Buried in the menus that configure the units, it is easy to overlook this configuration step, but if you do you’ll be undermining performance significantly.

With the D1 correctly connected to and configured alongside the C1 DAC/controller, listening could begin in earnest. From the first bars it was immediately obvious that this was a whole new ball game. From the obvious sense of presence to the tingling anticipation in the opening bars of the Sibelius, the added sense of poise to the playing (especially the soloist) and the overall sense of purpose and direction in the performance, the addition of the DAC brought the performance to life, adding color, drama and increasing both the acoustic and the space within it. With greater power, weight, and bandwidth on tap, the complex layers and evolving crescendos that are so characteristic of Sibelius’s work took on greater clarity, dynamic contrast and impact; they were more musically effective in every way. That added presence and weight as well as the broader tonal palette transformed the Pixies too. On "Here Comes Your Man," not only do the vocals step away from the backing, becoming more direct and expressive, but Kim Deal’s harmonies behind the opening lines emerge for the first time. There’s more shape to the guitar licks and the chopped bass notes, greater weight to the drums that likewise emerge from the mix, the whole song gaining drive and attitude. But more importantly still, along with the increase in motive force and direction, the whole song is more fun, the whole album darker and more powerful.

These results are no great surprise, although the scale of the improvement is, underlining that as far as disc replay is concerned this is very much a two-box solution. Once again, the combination's excellent performance on SACD comes to the fore, with impressive resolution and dynamic range backed up by an engaging sense of organization, purpose and body. Where many CD replay systems fall flat, sounding precise, but thin and often mechanical, the D1/C1 pairing maintains impressive musical integrity across both CD and SACD replay, with a brief foray into cross-format comparisons clearly underlining the benefits to be had from well-recorded or remastered SACDs. Those who doubt the value of SACD as a format might do well to hear it replayed on this rig.

If the benefits of adding the external DAC, another brick in this particular wall, are not exactly news and constitute something of a no-brainer, the next step in the process of building CH’s digital edifice offers possible alternative paths and is, as a result, less obvious. Like many of their high-end competition, CH Precision offers an external master clock, the T1 10MHz Time Reference ($24,700). This can be used with any of the digital-capable products in the range, from the D1 to the I1, C1 or C1d dual-mono DACs. The benefits of such an approach are widely recognized, and, indeed, in some cases, complex multi-box systems are almost unusable without an external master clock. The D1/C1 combination is an obvious candidate for this treatment, but before simply assuming that this is the next logical step on the upgrade ladder, there is an alternative. Almost all of CH Precision’s digital or line-level units offer users the option of adding an X1 external, regulated DC power supply   ($17,000) -- as featured in the P1 four-box piece mentioned earlier. Apart from the I1, the power amps and the T1 clock, every other unit sports a large multi-pin socket on its rear panel, just waiting to receive some nice smooth, ultra-quiet DC. Where things get interesting is that each X1 power supply can carry either one or (for an additional $3500) two regulation boards, meaning that a single X1 can be used to power both the D1 and the C1 -- which rather raises the question: is the next most effective step to add the T1 clock or an X1 dual-output power supply?

Prevailing logic amongst high-end digital engineers and marketers alike would suggest that this is also a no-brainer -- the clock is going to win out every time. So, for example, although both dCS and Esoteric, two of the most visible high-end, multi-box providers, offer external clocks for their DACs, neither offers any power-supply options. But the beauty of the CH Precision system topology is that we don’t need to guess or sign up to an article of faith; we can compare the relative benefits directly.

Adding the T1 clock to the D1/C1 pair is perfectly straightforward. You simply hook up the BNC leads to the appropriate sockets on the rear of the audio units (swapping the one for the C1 from output to input) and reconfigure the clock status in their menus to reflect the presence of an external master clock. Listening with the T1 attached, you’ll notice an immediate improvement in clarity and structure, the shape of what’s being played, separation of the players and individual focus. On the Sibelius disc, the violin’s elongated phrases have greater confidence and starker lines; shifts in attack and tempo are more explicit. You’ll notice similar benefits on the Pixies track, but here the changes seem more sonic than musical, with tighter playing and clearer delineation of musical parts at the expense of some heft and purpose in the performance. It’s more poised, it’s more refined and it's also arguably more polite, a quality that works for the Sibelius, but it is rather less welcome with rock music. Do these equivocal results suggest that the T1 clock can’t justify its cost? Whoa, Nelly -- we’re getting well ahead of ourselves here. First we need to replace the T1 with the X1 to hear what that contributes.

If the T1 is all about subtlety and the space in the performance -- the space between notes and the space between players -- the X1 is all about substance, color, life, and presence. Plugging the X1 into the D1/C1 drops the noise floor dramatically, bringing blacker backgrounds and increased focus, wider dynamic range and significantly more weight to proceedings. The result is more dimensional, more vivid images, a more explicit presentation, and notes and phrases that hit harder. The impact the X1 brings to the Pixies’ performance is dramatic, the difference between a good studio recording and a band that’s letting rip. The playing is solid and purposeful, the drums taking on a whole new and fundamental role, driving the music forward in concert with the more powerful contribution of the bass. The lyrics become more intelligible and far more effective, the voicing on a track like "Mr Grieves" more obvious and expressive. On the classical disc, the blacker background, broader acoustic and increased presence and dimensionality are welcome, as is the broader tonal palette. The complex layering in the orchestration is more obvious, if less clearly defined, and the crescendos far more dramatic. Here the tradeoff between substance and insight is more apparent, and therein lies the essence of your choice.

Should owners of a D1/C1 looking to take the next step opt for the X1 power supply or the T1 clock? Well, that depends -- on your system and your musical preferences. The clock brings clarity and organization, poise and pattern, qualities that come into their own on baroque or classical pieces, small-scale chamber works or the sort of intricate jazz typified by Coltrane’s A Love Supreme or the crisp, attack and sudden shifts of Ahmad Jamal. If you prefer the romantics, the likes of Rachmaninoff or Tchaikovsky, then the substance, body and easy rhythmic swell of the X1 power supply will be more to your taste. Of course, if you listen to rock or pop, roots or electronica, then the power supply is a shoo-in, its natural sense of substance, purpose, drive and attitude injecting just the sort of life and energy this music demands. This means that based on generic musical popularity, more listeners will find greater benefit in adding the X1 to their setup than plugging in the T1 -- food for thought, given the preponderance of clock options on offer when the body and presence that the power supply delivers are exactly what so many digital-replay systems lack. What about Sibelius? Well, he sits right on the cusp, with one foot on either box -- and that brings us to the real conclusion here.

Depending on your tastes, musical perspective and the overall balance of your system, the choice between the T1 and X1 is going to be clear. However, in most cases, that third box will only ever be a stopgap, a stepping stone to a four-box solution, because, as impressive as the results of either option can be, they pale into insignificance against the impact of the two together. If ever the whole was greater than the sum of the parts, the combination of the X1 power supply and the T1 clock is the perfect case in point. Their attributes, sonic and musical, dovetail perfectly, elevating the performance and appeal of the four-box solution significantly. With all four boxes working in concert, the presentation has a winning combination of substance, color, purpose, poise, refinement and clarity. The sheer articulation in Baiba Skride’s playing, the beautifully measured power in the orchestration, the towering crescendos and the dramatic contrasts with the solo instrument are as impressive as they are expressive. For the first time you get a real sense of Skride’s bowing and the effort and technique demanded by the piece. The timpani underpinnings gain texture, definition and subtlety to go with their weight; the almost sporadic orchestration takes on a sense of order and purpose, with Rouvali’s slightly naïve enthusiasm really apparent for the first time.

If the Sibelius disc is elevated, both as a performance and an experience, the Pixies take flight. Stepping away from the constraints of the speakers and the system, the band steps into your space. The drums pound like Gene Krupa on the charge, the chopped bass notes on "Here Comes Your Man" seem almost square, and for the first time you really get to appreciate the ghost of Lou Reed lurking behind the track. The Black Francis vocals reveal an almost propulsive quality to the newly purposeful performance and a more natural, intimate and communicative quality, reflecting the system’s musical qualities and integrity, encouraging you to listen longer and louder. Any process as involved as comparing these various options relies on a clearly structured and disciplined approach, with musical excerpts carefully chosen, kept short and changes in the setup made as swiftly as possible, yet with the four-box CH Precision player time and again I found myself not just running past the allotted musical limits but through whole tracks and ultimately the remaining eight tracks on Doolittle. Just as the two-box D1/C1 pairing completely eclipses the performance of the standalone D1, the four-box offers a huge step up over either of the three-box alternatives (a situation which spookily mirrors the relative steps in the P1 and L1 upgrade paths). As with the analog components, the various steps on the CH Precision digital upgrade ladder offer distinct and obvious benefits. To expect those steps to be evenly spaced is perhaps a fond hope too far, with the two-box and four-box solutions offering clearly defined plateau in the progression, with the four-box D1-C1-T1-X1 rig, in particular, offering a beautifully balanced set of musical virtues that are as appealing as they are satisfying.

or most companies that would be enough, with both the performance achieved and the quantity of hardware required stretching the limits, but in the great scheme of things CH Precision, we are not even halfway through the box count, even if we’re more than halfway through the steps. The next stage of the process at least has the benefit of a clearly defined path; there is only one way on from here and it’s defined by the DAC. Like the P1 and L1, the C1 DAC/controller is available in dual-monaural form, although, somewhat counter intuitively, that actually means three boxes not two, turning a four-box setup into six. Why three boxes? Because the incoming digital signal has to be greeted by a single interface and then split if you are to avoid creating issues and timing errors that will outweigh any advantages accruing from the channel separation. The familiar C1 chassis is joined by a further two, almost featureless boxes, each with the characteristic arc cut into its fascia and large central display, but no controls to speak of. The whole triumvirate is linked together using a further pair of the company’s proprietary CH-Link HD ribbon connections and in an unusual step, although it is standard policy for CH, owners of a C1 can have it upgraded to a C1d dual-monaural unit for the difference in the purchase price between the two. That amounts to $41,000. Is it worth it?

For this second round of listening I rang the musical changes, at least on the classical front, opting for a UHQCD of the Benedetti Michelangeli/Giulini Beethoven “Emperor” Concerto [Deutsche Grammophon Gesellschaft UCCG-90828], a 1982 live-concert recording from the Musikverein. The familiar acoustic and the scale of the solo instrument present new challenges for the upgrade path to meet. The benefits of the DAC upgrade were immediately and startlingly apparent on this piece, with a greater sense of space and transparency, a more definite acoustic that started to reach forward, a more measured, deliberate tempo, sweeter string tone and more instrumental color and texture throughout. The piano entry in the second movement carried greater precision and clarity to both the placement and weighting of the notes, and for the first time on either of the two classical discs, I could hear the conductor, his influence and complete control. It is a masterful performance from all concerned, and the C1d left no doubt as to that fact, its performance rendering the musical performance quite starkly beautiful.

Switching back to the earthier environs of the Pixies, the benefits of the dual-mono DAC were neither quite as apparent nor as musically important. There were certainly greater detail and focus, separation, instrumental texture and leading-edge definition. Instruments were more precisely localized and there was a definite spring in the music’s step, with guitar lines and vocal diction more nimble, drum patterns more clearly defined and the immediacy of the performance turned up a notch. But the insistent, toe-tapping sense of pace aside, these changes were more cosmetic/sonic than musically significant. The increase in rhythmic integrity and musical purpose is worth the entry fee; it’s just not as immediately obvious as on the acoustic/classical recording. You’ll notice it in just how engaging the music has become, how much longer you listen and your reluctance to cut into tracks, but those are more gradual realizations than the sonic shifts highlighted by a straight ABA comparison.

Of course, if those extra two DAC chassis didn’t offer the opportunity to add some extra power supply, then this wouldn’t be a CH Precision system. Drafting in another dual-output X1d external supply allows us to feed that high-quality, highly regulated DC to both of the independent DAC channels and it’s the next, obvious (and as far as this exercise goes, final) step. With the second X1d hooked up, it was back to listening with a bang, and once again, just like the combination of the T1 and X1 in the four-box setup, the pairing of the dual-mono DAC with the extra power supply punched way, way, way above its weight. The Beethoven piano concerto blossomed, with a quieter, blacker background and lower noise floor adding substance and color to the instruments, allowing the acoustic to reach forward and envelop the listener, bringing a fluid, almost pellucid, crystalline clarity to the piano notes and a new subtlety and sophistication to their spacing. This was a change that lifted the music away from the system and speakers, conjuring the Musikverein’s legendary acoustic and familiar tonal warmth, elevating the performance beyond mere hi-fi.

But if that was impressive, it did nothing to prepare me for the impact of the X1 on the Pixies’ presentation. All it took was the slashing presence and solid impact of the opening guitar chord on "Here Comes Your Man" to convince me that once I’d heard that second X1 in this system there was just no going back. That physicality and substance were injected into every aspect of the track, bringing body and shape to instruments and voices, a natural sense of relaxed pace to the performance. The whole was more communicative and engaging, coalescing around the voice, now more central to the mood and sense of the song. It was almost as if the X1 had picked up on all those sonic niceties added by the DAC and doubled down, binding them to the pattern and structure of the song, the instruments and the players. The step up in the relevance and convincing quality of the performance was simply massive, as was the increase in simple musical appreciation and enjoyment. The only downside? For rock and pop listeners I think that factoring in the additional cost of the X1d to the C1d upgrade is an essential requirement. The gains are so great that whereas a classical listener might move by steps through the DAC, adding the power supply later, most rock listeners will want what the power supply brings -- and want it now.

Graduating to the seven-box setup rams home both the quality of the CH Precision digital source’s performance and also the cost-effective upgrade ladder it provides. If you are in the market for even part of such a multi-box, multi-stage rig, then this is not only the best-sounding of the high-res, big-number brigade, but it is by some margin the most practical, considered and, in terms of stepped investment, cost-effective.

Whilst the CH components have never been and could never be described as affordable, the modular, expandable nature of the beast at least reduces the cost of entry and subdivides the upgrade path into bite-sized chunks (as long as you have a healthy appetite and the bank balance to go with it). In terms of the size of those steps, with the various upgrade allowances included -- yep, we’re talking telephone numbers. But by the time you get to a seven-box system, you are also taking one of the very best and musically most convincing digital-replay systems extant. It’s not the only game in town, but the extremely select competition, limited to the likes of Wadax, costs much the same. You pays your money and takes your choice. The difference is that at least with the CH setup you can reach Nirvana on the installment plan. Trying to get not just a stepped approach but an approach with even steps is too much to hope for, and that’s reflected in the description of the musical benefits accruing at each way station. But inevitably there are certain sweet spots or plateaus in the cost/benefit curve, and I’ve highlighted those. Even so, there are instances (program- and possibly system-dependent) where the intervening steps will still make sense.

The really frightening thing is that, while seven boxes might seem like a lot, there remains the option to add another two. Somewhere in the back of my brain there’s a nagging certainty that those X1d dual supplies are compromising the ultimate performance capability of the rest of the components. If the experience garnered with both the P1 and L1 are any indicator, swapping out the two X1d dual supplies for four, dedicated X1s, each feeding a separate box is going to reap serious musical dividends, although that requirement outruns my available stock of X1s, so I’m leaving it for another day -- when my patience and sanity have stabilized and I’m no longer seeing clock cables and power umbilicals in my sleep. What I can do is make an intermediate step, turning one of those X1d supplies into a pair of separate, single-channel X1s. Again and as noted above, CH’s differential cost equation comes to our aid, reducing the price of this switch to $13,500, rather than the $17,000 you might expect to pay for the additional X1 chassis. Even so, it takes the system total to an astronomical $193,200.

What it also does is bring us to another fork in the upgrade path -- and one of the more surprising results from this entire audio adventure: taking one of the X1d dual-output power supplies and turning it into a pair of single-output supplies. An X1d is one box with two independently regulated outputs, running from the same transformer. To turn that into a pair of single-output X1s, the customer buys another chassis (including the transformer and control circuitry/software) for $13,500 and then one of the regulator boards from the X1d is installed into it, creating two identical X1s in which each regulated output is connected to its own transformer. This change allows us to provide dedicated DC to two of the four digital boxes -- but which two? On the one hand, the independent left- and right-channel DACs seem like obvious candidates, but on the other there’s also the opportunity to give the D1 transport its own dedicated DC feed, along with the C1d head unit.

If I were a betting man, round about now I’d be reaching to put my money on the DAC-based solution -- which is probably why it’s a long time since I placed any bets. Using the single-output X1s to feed the DAC boxes certainly produces a clearly audible benefit. The noise floor drops, the intra-instrumental space gets blacker and more transparent, there’s more focus, the images are more dimensional, there’s greater depth to the soundstage, and the instrumental tone and texture are richer. Incidental details like kicked music stands or dropped items stand out more clearly and are more precisely located in space. So all good then? Well, yes and no; clearly the X1s allow the DACs to deliver more information, resolved to a lower detail, but (and it’s a very, very big but) there’s no improvement in temporal terms, no increase in the overall fluidity of the music or playing, the articulation of the phrasing or the sense of musical momentum. Instead, the results are somewhat the opposite, with the performance taking on the slightly disjointed and mechanical feel that so often inhibits the musical enjoyment of large, multi-box digital systems.

With all that food for thought quite literally ringing in my ears, I swapped the dedicated DC feeds onto the D1 and C1d head unit, with the DACs reverting to the shared supply. Sitting down to listen I wasn’t quite prepared for the almost shocking increase in musical purpose and momentum, substance, immediacy and presence. Suddenly bands and performers had more energy, more life and, crucially, more intent and attitude. Okay, so the level of transparency, separation and detail had dropped back to its previous (admittedly impressive) level, but the sheer vigor with which the music was delivered made it significantly more dramatic and engaging. Dynamics were more firmly rooted and precisely placed, the musical structure fitting together with greater clarity and impact, whether it was the Pixies’ building into a chorus or the order and continuity brought to the complex, layered structure of a Sibelius crescendo. Stepping sideways for a moment, to the familiar Du Pré/Elgar Cello Concerto UHQCD [Warner WPCS-284240], the solo instrument took on a presence and substance, Du Pré’s performance a sweep and swagger that brought this most emotive of recordings vividly to life. Feeding the D1 and C1d with dedicated supplies might not make the sort of sonic difference that feeding the independent DACs does, but musically speaking this was absolutely no contest.

Which should give us all pause. I have absolutely no doubt that going the whole hog and adding a ninth box (another dedicated X1 supply to allow the DACs to get individual DC too) would bind the sonic benefits previously heard to the musical integrity, structure, and purpose flowing so effortlessly from the front-end components. I’m equally convinced that, once again, the whole would be greater than the sum of its parts, but the hierarchy here is clear; the D1 rates an independent supply before you upgrade the X1 feeding the DACs. But, given the limited number of audiophiles with two-box CH Precision digital systems, the even smaller number who can afford to upgrade those to four-box rigs and the vanishingly small proportion of those who can take it up to nine boxes, the general conclusion is far more important.

If anybody still doubts the significance of power supplies to digital system performance, all they need to do is cop an earful of the CH Precision system. If I were the competition, I’d be scrambling to investigate the possibilities. If I owned a CH digital front-end, whether a D1, a C1 or both, I’d be looking to add the X1 at the earliest possible opportunity. Once you understand the significant musical contribution made by the external supplies, there’s an appealing logic and clarity to the CH Precision upgrade path. For once that logic is more than simply sonic or technical, but extends to and if anything makes even greater sense in terms of the musical results. That makes it both a boon and a no-brainer for CH Precision owners. For the wider industry, it’s an object lesson in digital audio engineering they’d do well to take on board.