CH Precision D1.5 SACD/CD player/transport Measurements

Sidebar 3: Measurements

I tested the CH Precision D1.5 SACD/CD player/transport with my Audio Precision SYS2722 system. As the D1.5 doesn't have digital inputs, I assessed its performance, using its own power supply and internal clock, with a Sony test SACD and a CD-R with 16-bit test signals.

I used the Pierre Verany Digital Test CD, which has gaps of various lengths in the data spiral, to check the D1.5's error correction. The Compact Disc Standard requires only that a player cope with gaps of up to 0.2mm in length, but the D1.5 played the tracks with gaps up to 2mm without audible glitches, which is excellent performance. However, the player wouldn't read the disc when a single gap was 3mm long or there was a succession of two gaps, each 2.4mm long.

The D1.5's output with a 1kHz signal at 0dBFS was 3.71V, balanced, and 1.85V, unbalanced, with both CD and SACD data. The balanced output impedance was a low 69 ohms from 20Hz to 20kHz. The single-ended output impedance was an even lower 31 ohms, again at all audio frequencies. The CH Precision's impulse response (fig.1) indicates that the player doesn't invert absolute polarity and that its reconstruction filter is a minimum-phase type, with all the ringing following the single sample at 0dBFS on the test CD track.


Fig.1 CH Precision D1.5, impulse response (one sample at 0dBFS, 44.1kHz sampling, 4ms time window).

With 16-bit white noise at –4dBFS (fig.2, red and magenta traces), the D1.5's response was flat up to 14kHz but then rolled off sharply, reaching full stop-band suppression at 21kHz, which is lower than the Nyquist frequency of 22.05kHz (green vertical line). The top audio-octave rolloff meant that a full-scale tone at 19.1kHz (blue and cyan traces) was reproduced at –36dB. An aliased image at 25kHz of this tone is present but lies at just –104dB (0.0006%). More significantly, the noisefloor above 20kHz is suppressed by 25dB compared with frequencies below 16kHz.


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

I examined the D1.5's frequency response in more detail, using spot frequency tones. Playing the test SACD (fig.3, magenta and red traces), the D1.5's output extended to 40kHz, above which it rolled off rapidly. With CD playback (cyan and blue traces), 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. 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.


Fig.3 CH Precision D1.5, frequency response into 100k ohms with CD data at –12dBFS (left channel cyan, blue) and with SACD data at –3dBFS (left magenta, right red) (1dB/vertical div.).

Channel separation (not shown) was okay, at 63dB in both directions from 20Hz to 20kHz. The low-frequency noisefloor, examined with a 1kHz tone at 0dBFS on the test SACD, was clean (fig.4), with no power supply–related spuriae present. This graph was taken with the internal supply. Repeating the analysis with the external supply gave an identical spectrum.


Fig.4 CH Precision D1.5, spectrum of 1kHz sinewave, DC–1kHz, at 0dBFS (left channel blue, right red; linear frequency scale).

Fig.5 shows the D1.5's output spectrum with a dithered 1kHz tone at –90dBFS from the CD (cyan and blue traces) and with a 1kHz tone at –60dBFS from the SACD (magenta and red traces). With the 16-bit data, the noisefloor is actually that of the dither. With the SACD data, the noisefloor drops by 20dB, which suggests a resolution of slightly more than 19 bits, and the third harmonic makes an appearance. With undithered 16-bit data representing a tone at exactly –90.31dBFS (fig.6), the three DC voltage levels described by the data were well resolved, the waveform was perfectly symmetrical, and the minimum-phase ringing at the bit transitions is visible.


Fig.5 CH Precision D1.5, spectrum with noise and spuriae of dithered 1kHz tone at –90dBFS with CD data (left channel cyan, right blue) and of dithered 1kHz tone at –60dBFS with SACD data (left magenta, right red) (20dB/vertical div.).


Fig.6 CH Precision D1.5, waveform of undithered 16-bit, 1kHz sinewave at –90.31dBFS (left channel blue, right red).

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). The level of this harmonic didn't increase when I reduced the load to 600 ohms. For consistency with Stereophile's measurements of digital products, I have showed the spectrum of the D1.5's output while it reproduced a mix of equal levels of 19 and 20kHz tones, the signal peaking at 0dBFS (fig.8). (The test signal was from CD-R, as the test SACD didn't include this signal.) The aliased images of the tones at 24.1kHz and 25.1kHz can be seen, but with the premature rolloff of the player's CD reconstruction filter, there are no intermodulation products visible. As was seen in fig.2, the ultrasonic noisefloor is almost 20dB lower in level than that in the audioband, which makes me wonder if there is also an analog low-pass filter present with CD playback.


Fig.7 CH Precision D1.5, spectrum of 100Hz sinewave, SACD data, at 0dBFS, DC–1kHz, into 100k ohms (left channel blue, right red; linear frequency scale).


Fig.8 CH Precision D1.5, HF intermodulation spectrum (DC–30kHz), 19+20kHz, CD data, at 0dBFS into 100k ohms (left channel blue, right red; linear frequency scale).

I tested the D1.5's rejection of word-clock jitter with the undithered Miller-Dunn J-Test signal. The CH Precision reproduced the odd-order harmonics of the LSB-level, low-frequency squarewave very close to the correct levels (fig.9, sloping green line), and no other sidebands were present.


Fig.9 CH Precision D1.5, high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz: 16-bit CD data (left channel blue, right red). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz.

As the CH Precision D1.5 has digital outputs, to allow it to be used as a transport, I examined the quality of those outputs. Fig.10 was taken from the TosLink output with 16-bit J-Test data plotted over one "unit cycle." The eye pattern is wide open, with almost no blurring of the leading and trailing edges. The average jitter level, assessed with a 50Hz–100kHz bandwidth, was very low, at 340.5ps. Repeating the test with the coaxial S/PDIF output gave an identical eye pattern but with just 253.9ps of jitter. Turning on 2× upsampling gave a similarly wide-open eye pattern (though half the length of that shown in fig.10), with 340.5ps of jitter.


Fig.10 CH Precision D1.5, eye pattern of TosLink data output carrying 16-bit, 44.1kHz J-Test data (±2.5V vertical scale, 175ns horizontal scale).

The CH Precision D1.5 offers generally excellent measured performance. It performed well as a transport and with SACD playback, but I remain puzzled by its premature high-frequency rolloff with CD playback (footnote 1).—John Atkinson

Footnote 1: See CH Precision's Manufacturer's Comment.

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.