CH Precision D1.5 SACD/CD player/transport Page 2

CH Precision's approach to optimizing timing in digital audio has much in common with the MQA approach. CH Precision tries to achieve as much time compaction as possible without having access to information about the ADCs used in the original digital conversion—and, of course, without MQA's controversial "audio origami," which reduces file size. Of course, MQA wasn't the first to think about these things, either. Heeb told me that this line of thinking goes back at least to the late 1980s, to Luxman's Fluency DAC, a design based on the splines-related DSP work of Professor Kazuo Toraichi of the University of Tsukuba in Tokyo. Other early splines users in digital audio include Robert Moses of Wadia and Pioneer products employing the "Legato Linear" filter.

A related issue—related, that is, to timing precision—is phase coherence. Heeb: "Phase coherence is extremely important, we find out. What we mean by phase coherence is how the phase at a given frequency compares to the phase at neighboring frequencies. It is important to keep a certain level of what we call coherence between the phase response of adjacent frequency bins. This is one of the key points of the digital filters that we use in the D1.5." Consequently, Heeb told me, when we measure the frequency response, we'll "see that it has a little bit of a rolloff at 20kHz." (Actually, we found more than a little bit, but only at the highest potentially audible frequencies: See the Measurements sidebar.) "On the other hand, it has a very short time localization and implements to the full this concept of phase coherence that I was talking about before. That's really the essence.

"The other very important point that we have in those digital filters is the minimization of the errors in the computing itself," Heeb said. "A typical example would be the errors that round up when you do floating-point representations and [when] you do additions of very large and very small numbers that will create a distortion due to the limited precision [of] floating-point numbers." Get the calculations right, in other words.

That's the CH Precision approach to digital, as manifested in the D1.5, in a hefty nutshell.

In use
Once you know how to operate it, the control system on the D1.5 is simple and elegant. On the right side of the front panel are two coaxial knobs. Turning the inside knob to the left opens the CD drawer. Turning it to the right closes the drawer. Turning it to the right again initiates play. Turning it to the left stops play. The outside knob, turned clockwise, moves the player to the next track; turning it the other way moves it to the previous track.

The inner knob is also a button; pushing it provides access to the Setup menu, which can then be navigated, intuitively, via the two knobs.

You can also set up most functions on the D1.5, and on other CH Precision products, using the CH Precision app, which. However. is only available on the Android platform: No iOS (Apple) version is available. There's also an elegant, chunky, metal remote control, with minimal functions: Play/Pause, Stop, Forward, Back, Mute. Some functions can only be performed on the player itself, via its setup menu. If you want to choose a different layer of a multilayer disc—say, the MQA layer on a hybrid SACD/MQA-CD disc, such as those from 2L or Impex, you'll need to get out of your listening chair.

Reviewing the D1.5 proved a logistical challenge because most of my silver discs are in storage. My reference recordings are mostly files and LPs; I also utilize Qobuz and Tidal for reviews. None of that is helpful in reviewing a transport/player. I dug through boxes to access a few CDs; otherwise, I relied on discs I've received over the last couple of years as promos and review copies.


The first disc I chose was Radiohead's Amnesiac, on a regular CD (Capitol CDP 724353276423), which I had recovered from its storage box a few months ago because I wanted to listen to it in my car. I bought this disc at a Barnes & Noble in northwest Washington, DC, during a month-long stay in that city years ago when I was starting a new job. I recall walking along the Lincoln Memorial Reflecting Pool on a rainy Saturday and lying still on the bed in a meditative state in the basement room I was staying in, listening to this on a portable CD player. This is how Records to Die For are made.

This disc sounds plenty good on anything, including that portable player and whatever cheap headphones I was using circa 2001. Did I hear any advantage to this expensive player? Yes, I did: It was most noticeable in the bass, which felt more fundamental (with emphasis on the root of that word, fundament): seismic weight, especially on the 10th track, "Like Spinning Plates." On the third track, "Pulk/Pull Revolving Doors," in the electronic interlude that starts before 9:00, percussion had real, physical presence in the room, even though much of it is electronic. On the final track, "Life in a Glasshouse," the feeling of immersion, amidst a noodling quasi-Dixieland jazz band, was as powerful as I've experienced with two-channel audio, even as I sat 12' from the Wilson Alexx V speakers. Thom Yorke's voice, as haunting as ever, just hung there in space between the two speakers.

From there I moved on to Vladimir Ashkenazy's 1965 recording of Chopin, Debussy, and Ravel on a 2007 CD (Decca 475 8499) from Decca's "The Originals" series. It's a superb performance—the young Ashkenazy was a machine, although a very human one—and a very good-sounding CD. The piano sound is very natural from top to bottom, and the instrument has real, tangible body when it resonates in the lower part of its range.

There's not a lot to say about its reproduction by the D1.5, and I mean that in the best way. The recording sounded the way I've come to expect it to sound, with real sparkle in the highs, lovely tone in the midrange in the powerful, soft passages, and real power when the pianist plumbs the depths. The image of the instrument has depth; you can hear the notes moving back to front as he runs up and down the keyboard. Better piano recordings exist, but this disc—as played back here—makes a strong case for "Red Book" CD as a valid high-end container for acoustic music.


Clique, the latest album from Patricia Barber, with liner notes by Stereophile jazz critic Tom Conrad, was engineered by Jim Anderson, who has won three Grammy Awards and may well win a fourth, for this recording. (He has already been nominated.) Anderson also wrote the My Back Pages column in the February 2022 issue of Stereophile.

Clique is a beautifully recorded album, and much more musically interesting than it seems on first listen, but it took a while to grow on me. The silver-disc version from Impex includes audio in three formats: stereo and surround DSD and MQA CD. Listening at first to the stereo DSD layer, I had the repeated impression of being pleasantly surprised by aspects of the sound—the way particular sounds emerged from otherwise empty space, by the creamy texture of one of Barber's vocals (as on "The In Crowd"), by the realism, that in-the-room feeling. Such things caused me to smile and look up with something like delight. It made me think Jim Anderson must have been having great fun sitting at the console, collaborating with Barber and the other musicians in creating this.

What is it about this music, produced by this player and this system, that makes me respond this way? It feels like surprise, the unexpected. Little pearls of piano notes, almost visible, float in space, each with unexpected nuance, inflection, and tonal color. It can be a surprising bit of imaging or surprisingly deep and resonant bass. I sense that dynamics are important in this. Music that's dynamically compressed loses that sense of surprise. Dynamic compression is imposed monotony.

What causes this sense of surprise? I can tell you what it feels like (footnote 3). It's novelty. Nonuniformity. No order is imposed; the individuality of each sound is preserved. This makes me think of a concept in Zen—the pattern that is no pattern, the pattern of perfect randomness, like the pattern leaves form on grass after falling from a tree. No conscious mind could arrange them that way. This is something like that: Natural patterns are untainted. They remain interesting, colorful, artful, human.

Sometimes, in listening, it's not clear what is surprising, what keeps us engaged or re-engages us, but something is. Something does.

One thing I noticed early on in my time with the D1.5 is how good it sounds at low volume. This sense of surprise was present even—perhaps especially—when the music was playing at background levels. Notes kept their shape—their character—even when the music was quiet.

Why is this all better through the D1.5? Surely, to make a great player, you've got to get a lot of things right, but what sets the D1.5 apart? Considering the focus of Heeb and Cossy in designing the D1.5, as expressed in the interview above, could it perhaps be the timing?

As a final experiment, for now: Using the CH Precision app, I changed the clock source from the D1.5's internal clock to the T1 Time Reference, which was already connected. I don't really understand the use of external clocks when you're using just one high-quality component. If you've got both a transport and a DAC that need to work together—well, then it certainly makes sense. But with just one component, isn't the most important thing to put the clock as close as possible to the digital converter? The external clock would need to be very much better to offset the disadvantages of being external.


I was listening to a recent acquisition, En attendant from the Marcin Wasilewski Trio (CD, ECM 2677). With the internal clock, the sound was very good—remarkable in some ways. There was plenty of surprise—sounds popping up all over the stage, with interesting timbre and tonal color, lots of wood and sparkle. But when I switched in the T1 Time Reference, the improvement wasn't subtle. Though I'd been completely unaware of it—completely happy with the sound—it now seemed as though the music had been slouching and now it snapped to attention. More depth, more separation. The stage was slightly bigger, slightly deeper, more erect. Percussion instruments became more distinctive in timbre and in their position in space. The remarkable thing was that now bass had extra impact, quite apparent on the louder low notes of the piano and the upright bass. I don't know why an external clock would make the bass more forceful, but this last experiment makes me think: Yes, it must be the timing.

From the time I first heard about it, MQA CD seemed like an interesting idea. On the one hand, on a 16-bit CD, there's no place to squirrel away data, as MQA is known to do on 24-bit files. On the other hand, if it's true—as both MQA and CH Precision believe—that time smearing is a serious issue in digital playback, then correcting it is likely to be much more audible at CD resolution than at higher resolutions, where filtering need not be as aggressive.

The numbers are still small, but there are more MQA CDs out there than I realized. Most are on audiophile labels such as Impex, 2L, and Eudora—but the format is becoming more mainstream: Some recent Doors reissues on Rhino/Elektra include MQA CD, and a series of rock-pop MQA CDs (Blondie, Police, Stevie Wonder, King Crimson) has been released in Japan, available as imports at, eg,

Until now, I'd never had an opportunity to listen to an MQA CD on an MQA-CD–enabled player. (How many such players exist?) Patricia Barber's Clique has an MQA layer. It's time to compare it to the SACD layer auditioned above.

I created a shortcut to switch layers, which is very easy to do. Once the shortcut was created, switching layers was trivial, although after each change, the player has to read the disc again, which takes several seconds.

The first thing I noticed: The MQA layer is significantly louder than the SACD layer, by perhaps 3dB (footnote 4). So, for the comparison, I lowered the volume by 3dB.

On the MQA layer, "This Town" (first track) sounded superb. Barber's voice had a lovely, creamy texture. Slap was accentuated on Patrick Mulcahey's bass. After the 2:00 mark, as the music got louder, I detected some congestion. Textures thickened. It was subtle.

Switching back to the SACD layer (and increasing levels by 3dB), I didn't hear as much creaminess on the vocals, but they didn't sound worse—just different. I listened for that congestion in the louder parts. I didn't hear it.


Wrapping up—for now
One of the reasons that audio is so addictive—and takes such a big hit on our pocketbooks—is that we get used to a certain level of performance. We raise our systems to a certain level and acclimate. We stop noticing the surprise, and the music starts to bore us again. There are ways around it: meditation, rituals, certain substances—but if we don't employ those or other methods, we may soon find ourselves craving something new, better, and probably more expensive.

Except that sometimes, at a certain level of performance, this doesn't happen anymore. The music keeps surprising us. That level may be different for each of us. Lately, I've had the privilege of listening consistently to very good equipment—I'm used to good digital—and after several months with the D1.5, I never got bored. If that sounds like faint praise—well, it isn't.

Software, of course, is a major variable, which is why I chose a superbly recorded disc—Clique—for the most important bit of listening. Some digital recordings have monotony encoded in the bits and pits. Among the CDs I recovered from those boxes was a Philips recording of Schubert's Winterreisse by Dietrich Fischer-Dieskau, with Alfred Brendel on piano. It's an early digital recording, from 1985, remastered and reissued in 2001 as part of the Philips "50 Great Recordings" series. It's not a bad recording, just a bit dim: monochromatic and lacking that element of surprise. A player can't dig out what isn't there. Probably.

I've mentioned that I have the whole CH Precision digital system here: the D1.5, the C1 DAC, the T1 clock, the X1 power supply, and a bunch of very expensive cables installed for this review. It's all stacked (appropriately, using CH Precision's interesting stacking system) on an HRS amplifier stand. That's $136,000 worth of CH Precision components, plus the cables and stand. I'm not letting it go before writing about how it all works together—but that will have to wait. For now, my work here is done

Footnote 3: See this month's As We See It.

Footnote 4: Later, I confirmed a 3dB difference by comparing maximum levels.

CH Precision
(41) (0)21-701-9040

volvic's picture

Great review; I would have been happy reading even more technical info and how these engineers think. Do the engineers at CH believe that 16 bits are good enough for Red Book replay?
It was nice to read their attention to the transport, a pet peeve of mine on expensive players. The best machines I ever heard and owned were in-house-built transports or heavily modified ones; Wadia, Linn, Luxman, Esoteric, and others used well-designed solid transports to minimize vibration.
I would love to hear CH products with SACD recordings. It is a shame that format never really took off. Its built-in copy-protection limited how it could be used and connected to other components.
Great review; I can’t wait to read about the other related CH products.

Glotz's picture

Perhaps an extra box with anti-theft lasers??

Zero mockery of CH Precision. If I had lottery money, these would be mine tomorrow.

volvic's picture

I would sit down and here these beauties the Goldmunds, and the Esoterics. I betcha it would be a really tough call.

Kal Rubinson's picture

Its built-in copy-protection limited how it could be used and connected to other components.

Those problems were solved a long time ago. SACD failed because of marketing errors and the underlying issue that improvements in sound quality rarely have any impact in the mass market.

volvic's picture

Maybe, but I still can't bypass and use the digital out or hdmi out for better sound, and I paid a fortune for it in 2004. Only through the RCA jacks. Don't disagree with the sound improvements, goes without saying, most don't care, except for us subscribers and readers to Stereophile.

Kal Rubinson's picture

Of course, it depends on one's choice of machine but 2004 was probably just too early. HDMI 1.2 (released in August 2005) added DSD support for transmission of SACD content at up to 8 channels.

volvic's picture

The downside of being an early adopter. Maybe time to upgrade. Thanks for the info.

Kal Rubinson's picture

Yeah but now you may be too late. :-)

volvic's picture

You’re probably right, don’t see many sacd machines with hdmi outputs nowdays. Maybe source a used one.

Robin Landseadel's picture

Managed to find two Sony Blu-Ray players, used and crazy cheap, within the last 4 years. One for $20, the other $7. SACD capable, HDMI out, also digital coax out, which is what I use on those very rare occasions I play a CD. I suspect the coax out converts the DSD stream to PCM. In any case, single layer SACDs play just like the CDs with these players. Most of the time I rip the contents of the CD to a SSD, back that up on a Micro SD for a DAP, connect a USB out on the laptop to a Topping E30, use the I-Tunes playlist. Found remotes for the Blu-Ray players online, about $10 each.

"The CH Precision player featured very low levels of harmonic distortion, with the third harmonic the highest in level at –100dB with SACD data (fig.7)."

From the measurements I've seen, the Topping E30 [$150, give or take] beats that spec by -10db.

RH's picture

Inured as I thought I was to expensive items reviewed in Stereophile, when I came to this sentence:

-- "Equipped as a transport—with, of course, a digital output card—the D1.5 costs a formidable $41,000."

...I literally choked on my food. Actually gagged.

Ok, maybe it was partially due to my wife's occasionally clumsy attempts at Banana Bread. But still...that price seems at least as hard to swallow as my wife's banana bread.

Somewhere at Benchmark, someone is smiling. ;-)

Axiom05's picture

Is it April 1st already? A review of a pre-production unit, a $41K CD/SACD player? OMG, MQA-CD alone should be a joke. No disrespect for the designer but this one really makes my head spin. There are so many better options available at a fraction of this price.

tonykaz's picture

What happens if you scratch it up ?

I just did a small real estate deal involving a Bank and $150k. I needed to present something for them to hold onto of much greater value.

Hmm, is this how you lads secure loaner gear ?

Of course, for selfish reasons, I would encourage you to do a long term test, if it was my company's gear and I was certain that you would be THRILLED with it's performance enough to publish gushing accolades of greatness.

I personally would "OWN" great discovered Gear because outstanding is so rare and hard to come by. ( unless other factors (like $ cost) make it prohibitive )

That CH gear needs to hold 80% of it's MSRP and even then it's still too pricy. ( for me )

Tony in Florida

teched58's picture

The solution is to have one's butler stand next to this $̶5̶ ̶m̶i̶l̶l̶i̶o̶n̶
$41,000 CD player to make sure that the drawer does not get bumped or bent. Dunno what Jeeves can do about the fact that you're paying a very small portion of your Wall Street bonus for a player that has old firmware. Maybe if Jeeves is an ex-IT guy (e.g., he's over 40 so was laid off from his corporate gig) he'll be able to download it for you. Just make sure he remembers to close the CD drawer! Oh, and Jeeves is old enough to explain to you what a CD is and why they were once popular.

Archimago's picture

Wow, this sounds really fancy:

"It's compact support," Heeb said. "This is exactly what I was talking about before when I told you we want to reduce the time smearing. Time smearing is basically if you put a single pulse through the system, if you have a filter with a very long impulse response, that single sample will extend over a large number of samples. We prefer to use splines, which have a much more compact support, which makes it so that when the sample goes in, what comes out has, in our case, [no more than] 100µs of pre-ringing and post-ringing." 100µs is the target because it's a level of timing precision where errors are thought to be audible. It's a conservative figure; I've seen estimates in the literature as low as 5–6µs.

Come on guys, it's just a minimum phase, moderately steep, digital filter that rolls off quite early around 15kHz with a stopband frequency below Nyquist.

Nothing all that fancy about this at all. Nothing requiring thousands of dollars to perform.

In 2022, looking at an impulse response and talking about "blurring" as if this is even a "timing precision" issue as if audiophiles haven't maybe thought about this already is looking really, really silly! This is the kind of misinformation that MQA has been trying to perpetuate for years.

Come on Stereophile, time to move on. Enough with nonsense! Minimum phase filters introduce timing/phase shifts whether it's with this device or the MQA filters.

supamark's picture

You should read them. Turns out the item under review had old firmware and was using an incorrect filter. They're going to do a follow up with the correct filter/software. The filter makes a huge difference to the sound, so I'm curious what Jim will hear and hopefully some add'l measurements too.

Mark Phillips
Contributor, Soundstage! Network

Kal Rubinson's picture

I suspect the coax out converts the DSD stream to PCM.

That or you are playing the CD tracks.

Robin Landseadel's picture

Again, a single-layer SACD doesn't have a Redbook layer, at least that's what I've read elsewhere.

This [obviously cheap] Sony BDP-BX57 Blu-Ray player I'm now using is nearly "Universal". When I had a 5.1 system, it would play back 5.1 DVD-A discs via the plainwrap DVD layer, surround courtesy Dolby. I thought I heard a difference between that and true DVD-A, but not enough to really care. I once had an OPPO DVD-era player, great with DVD-A, but would hang like the other DVD-A players I've used. However, the Sony would play my copy of Beck's Guero all the way through as a DVD. As DVD-A, it would regularly hang, probably because of that disc's amazing, constantly fluctuating visual presentation rendered on the fly.

Kal Rubinson's picture

Again, a single-layer SACD doesn't have a Redbook layer, at least that's what I've read elsewhere.

Yup but some people mis-use that term.

The "hang" problem you describe is not something I have come across with any of the Oppos (or, for that matter, with any player I've owned) except with a rare faulty disc. That includes DVD-As and single-layer SACDs.

Robin Landseadel's picture

I had no issues with DVDs in my OPPO otherwise, I suspect "Guero" may have bitten off more can it can chew.

jtshaw's picture

My Bryston BCD-3 feeds a balanced input on a Luxman L-509x integrated amplifier, which in turn sends the music to a pair of Joseph Audio Pulsars. My entire system comes in at much less money than this CH Precision transport/player.

I would not be surprised if the CH Precision provides superior performance, but how much better? In my actual listening experience, the Bryston BCD-3 comes very close to a dCS Puccini. I suspect performance improvements are truly at the outer margins.

I don't begrudge anyone their purchase if they can afford to buy and enjoy the CH Precision, but in this case they are likely buying at a point where the curve of diminishing returns has already long gone nearly vertical. Much of my pleasure in audiophilia has been putting together systems that to my ears hit that point where curve starts its nearly vertical climb.

volvic's picture

The BCD-3 is one of the finest DAC's I have ever heard and agree. However, done right on some of the best machines, SACD can sound revelatory. While SACD may be on life support in North America, I suspect it is still going strong in other places, most notably Japan. Hence why these machines exist. I wish it had thrived, it has this clarity and hyper-detail that even my SME and Roksan vinyl rigs can't sometimes match. It can get fatiguing over long listening with some of my limited discs but, other times, it is very impressive.

HighEndOne's picture


Because I would think that some form of “control” or “standard” might be helpful in forming a good and valid review, and those constraints seems to be missing here. But then again, we are mostly talking about a subjective critique, not a scientific evaluation.

The reviewer is moving (or has moved) so he has no access to his reference music material. OK, yes you can stream files. Do you really know what is coming down that ethernet line at that moment? To my mind, it is a variable.

This may also mean he is in a new, or newer, listening room. I, for one, do believe that the room is a particularly important component to the results one hears.

Likewise, some of his associated reference equipment may also be unavailable. I will gladly stand corrected on this point if needed.

Perhaps unknown to the reviewer at the time, the unit being evaluated is a pre-production unit. I could say it is a possible "ringer" if were not for the JA (John Atkinson) measurement failure listed below.
The unit in question measures poorly in the frequency response area (Per JA -Redbook). Did the listening tests miss this? And what about the frequency response of the reviewer’s ears? Can we measure those as well?

After JA measures the sample, the manufacturer now admits that this pre-production unit was released with down-rev software and that the settings for some functions are less than clear. But of course, CH says they can send you the updated code that YOU can install. (BTW, since my technical time is worth $500 per hour, is CH going to reimburse me?) And I guess I can download, and then print, the new, revised operator’s guide too.

Now let me say that CH gear is likely built to an extremely high “Swiss” standard overall, and that the intent at CH is to surpass the competition. Of this I have no doubt (my father was a watchmaker, so I know a little about the Swiss approach). And I also must admit that I have never seen, nor heard, CH gear in action. I can only say that my exposure to decent gear (my older Levinson stack: 38S – 37 – 360S) gives me a taste of what can and should be possible at the even-higher price echelons that CH inhabits.

Nonetheless, CD audio nirvana is just $40K away, right? Maybe for some. Not for my money, thank you. Why? How will I know that MY $40K unit is meeting specifications or not? Do I need to ship it to JA to confirm that MY unit is working correctly?

Over the many years I have read this magazine, there have been instances of expensive gear getting rave reviews, only to be found to have, shall we say, less-than-stellar measurements. Then we will see the associated manufacturer’s comment that the unit was either defective, mishandled in shipping or “fill-in-the-blank”. Is this is supposed to make it all better? And please do not recite the banner statement that all that really counts is the sound of the item under review. If MY new Corvette, for example, looks great but (unbeknownst to me) will not break 120 MPH, what is the point? I paid $75K or $100K for what?

And on a loosely related topic, how can Michael Fremer stand behind years of review work, when by his own admission, until recently, the AC power quality to his reference rig was, to be charitable, quite questionable, and a long-term problem? It is great that he documented all the effort taken to rectify (no pun intended) his AC issues; it just makes me very uneasy when five and six figure gear is placed on a pedestal that might be made of sand (bad power).

In closing, despite my ranting and raving here, please keep up the excellent work you folks do. You should know that the first thing I look for in your reviews is the JA measurements section. Once I am past that, then I will read the “opinion” portion of the article.

And this also keeps me from “absolutely” investing in that other magazine. There are no independent measurements to back up anything said there.

All the best… HighEndOne

David Harper's picture

So then I take it this thing is better than my OPPO 203?

shawnwes's picture

It's one thing to have a news blurb about a soon to be released product but to do a review on a non-production sample goes against the standards your readers expect from Stereophile. Readers have no idea how this unit might be different from an actual production unit. The fact they had "incorrect software" loaded in a $40k unit under review is a very bush league answer even if it is true.

Andrei's picture

"Reclocking salves all digital wounds, or so this thinking goes." I am in in this camp. The errors in clocking would have to be huge for the re-clocking to to work, I doubt there is a transport that would be that bad.

But it is worse than that. These days the transport can be PCM or DSD files held on a SS hard drive. It is not difficult to get an unpolluted USB or a I2S or other method to get to a DAC that will equal this unit. So in effect this vast sum is being paid for a transport that is not needed. I guess you would have to be invested in (SA)CDs, like the idea of the physical media, and be well heeled. Maybe there is some cachet in just owning such a piece.

Johnnyjajohnny's picture

Sorry to be a party pooper here, but a channel separation of only 63 dB?
I was just looking at Stereophile's measurements of Arcam's FMJ CD33, which is not exactly new or cutting-edge or whatever you would call it (nor so expensive), and the channel separation for most of the audioband for that unit was more than 120 dB.