CH Precision D1.5 SACD/CD player/transport New Firmware

Listening to the New Firmware, May 2022 (Vol.45 No.5):

When I reviewed the CH Precision D1.5 player/transport in the March 2022 issue—I reviewed it mostly as a player—I was very much impressed by its performance (footnote 1). It was at its best as a SACD player. It also sounded very good playing MQA CDs. (It was my first experience hearing an MQA CD on a capable player, so I had little to compare it to except the other formats.)

The sound on CD was exemplary—probably the best CD sound I'd heard—but it was not as good as with the other formats. Which was expected (footnote 2).

When JA measured the D1.5, he found that when playing CDs, the D1.5 was not, however, behaving as expected. In the time domain, he observed a conventional-looking minimum-phase filter, with no pre-ringing but 5–6 periods (about 550µs) of post-ringing. In the frequency domain, he found a very fast rolloff: With CD playback, the response "was flat to 12.5kHz but then was down by 1.1dB at 15kHz, by 3.9dB at 16kHz, and by almost 10dB at 17kHz." At 20kHz (widely considered the top of the audioband, although at 58 years old I can't hear that high), the response was down by a full 50dB. "With the ear's reduced sensitivity in the top audio octave, the premature rolloff will be difficult to hear, but it does suggest an error in the programming of the digital reconstruction filter," JA wrote.

In a manufacturer's comment, CH Precision CEO Florian Cossy acknowledged the error. "John Atkinson's measurements are completely correct in identifying the early rolloff on CD replay, and Jim is also correct in suggesting that this might well be atypical. The measured results suggest that the machine is using a minimum-phase apodizing filter rather than the proprietary PEtER spline filter that should be engaged. ... It seems that the firmware in the (preproduction) D1.5 supplied for review has selected one of the minimum-phase filters from our library of available algorithms." Full-production D1.5s already in the wild had already had their firmware updated remotely.

Almost immediately, CH Precision sent along a file with the new firmware. The installation went smoothly; the procedure was, as doctors write in diagnostic notes, unremarkable. I am not the kind of listener or reviewer who obsesses over filters. In fact, while I understand the rationale for providing a choice, I find user-selectable reconstruction filters slightly annoying. To me, the changes they make to the sound tend to run from inaudible to relatively unimportant—not qualitative, let's say. In any case, I don't like too much choice: Please just give me your best sound and let me listen to music.

Yet, with the new firmware, the transformation in the sound of the D1.5, when playing CDs, was qualitative. It was major. It was also transient, in the sense that my ear-brain adapted to it quickly and then it was gone.

I don't mean to suggest that a window opened up to the studio or the live performance space, where there hadn't been one before. The change was dramatic, but it wasn't necessarily—wasn't immediately—a giant leap forward in absolute sonic quality. It was, rather, simply a major change in sonic character.

The change was a one-off—I couldn't go back and forth (footnote 3)—but as often happens with me, because I get distracted listening to music, I didn't take notes. Here's what I remember: Whatever CD I was listening to at the time, the sound was suddenly more spacious, the soundstage deeper, the experience taking on a silvery, shimmering quality that I had not noticed before.

This was a transient, differential impression. As I continued to listen—as I acclimated to the new sound—I stopped noticing any silvery, shimmering quality. I just heard music. When we listen to music, we don't listen differentially. We just listen. Well, hopefully we do.

I wrote just now that the change, profound as it was, was not an immediately obvious giant leap forward in quality—and yet, as I learned over weeks of subsequent listening, it was an improvement and an important one.

I'm as big a fan as anyone of precision, weight, corporeality of images, fineness and beauty of tone. But I find myself evaluating digital sources in particular in terms of how clearly and intensively they reveal the specific character of each recording. That's not some ethical or abstract principle of reviewing; it's just what I notice first and most.

Also, I don't pretend to know a priori what the recording sounds like. It is, rather, a feeling I have when I listen. Different recordings sound profoundly different, and certain sources reveal those differences much more obviously than others. Instinctively, my mind forms a coherent, semivisual image of the sound of a recording as a whole.

French-American jazz pianist Jean-Michel Pilc was previously unknown to me, but he made me an immediate fan with his new CD Alive (Justin Time JUST275-2), with bassist Rémi-Jean LeBlanc and drummer Jim Doxas. The recording documents the trio's first date playing together since the pandemic started. I am a fan of the music, yes, but also of his (Pilc's) liner notes. He writes, "In my vinyl collection, there are quite a few items I treasure. The sound is not perfect but you can hear improvising musicians in their natural habitat, the jazz club, playing music for the sake of music." Yes, exactly this. What made me laugh out loud when I read these notes is that the album Pilc describes is exactly the album I'd just enjoyed (except that this is a CD, not an LP; it's available streaming, but it does not seem to be available on vinyl).

The sound? Enjoyable. Imperfect (footnote 4). A bit dark and—smokey, like an image of a jazz club that's no longer accurate, since there's no actual smoke these days in jazz clubs. The character of the recording—you could even say the recording's flaws—helps to fulfill the recording's objectives; it supports the feeling of a live date in a jazz club (It was recorded at Dièse Onze in Montréal).

Via the D1.5, this lack of clarity was rendered colorfully, with perfect clarity.

JA sent me test tracks so that I could repeat some of the measurements he made on the D1.5—those that showed severely attenuated extreme highs in the frequency response and a minimum-phase but rather long response in the time domain.

Fig.1 CH Precision D1.5, frequency response with CD data at –12dBFS and new firmware (left channel blue, right red) and with original firmware (left green, right gray) (1dB/vertical div.).

Fig.2 CH Precision D1.5, new firmware, wideband spectrum of white noise at –4dBFS (left channel red, right magenta) and a 19.1kHz tone at 0dBFS (left blue, right cyan) with data sampled at 44.1kHz (20dB/vertical div.).

My frequency-response measurements, with the new software, showed a much slower rolloff than before (fig.1). The aliased image of a full-scale 19kHz sinewave, at 25.1kHz, was suppressed by just 10dB (fig.2, blue and cyan traces; the background noise is due to the interface used).

Fig.3 CH Precision D1.5, impulse response with new firmware, 44.1kHz sampling (4ms time window).

Fig.4 CH Precision D1.5, impulse response with old firmware, 44.1kHz sampling (4ms time window).

The payoff is in the time domain (fig.3): a remarkably short impulse response—symmetrical, lasting only about 50µs from the first wiggle to the last—far shorter than the 500+µs impulse with the original software (fig.4). It is however very similar to the impulse response of the SR (slow-rolloff) filter with for example, DACs based on the ESS Sabre 9028 Pro, though perhaps a little shorter.

Do changes on such a short timescale make a difference? Apparently they do—a major sonic difference, at least as I heard it. I suppose I could be hearing the frequency-domain manifestation instead, but it hardly seems more likely that I'm hearing a 1.1dB change at 15kHz when that's approximately the current high-end limit of my audible range. This experience seems much better aligned with what I know about the time-domain acuity of human hearing. I'm not entirely sure, though, that it's a meaningful distinction, since the frequency and time domains are complementary ways of conceptualizing the same thing.—Jim Austin

Footnote 1: The D1.5 costs $41,000 equipped as transport, $46,000 with two mono analog-output cards.

Footnote 2: Except that those who have convinced themselves, whether on technical or moral grounds, that MQA is inferior would find my conclusion that MQA CD sounded better than regular CD unexpected.

Footnote 3: I could have requested that CH Precision send me the old, faulty software so that I could reinstall it again. It would have been a bit tedious, the process unwieldy, but I could have gone back and forth between the two versions. Still, I didn't.

Footnote 4: In those same liner notes, Pilc acknowledges "the shortcomings of the recording" but attributes to mastering engineer Guy Hébert the fact that the end result is "the final impression is actually pretty close to what you do experience in the venue." Again Pilc made me smile with his writing: I did not read this until after I had drawn precisely that conclusion.

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.