December 2019

CH Precision Ethernet Streaming HD Board Review
CH Precision moves us forward in the right direction.
Review By Marshall Nack

  It's winter time. Want to know the best tweak for the season? Humidity. Get a humidifier and maintain about 35% RH at the equipment rack. Not only does it make you feel better, it will make the equipment perform better. Sound travels through air: consider it the final wire in your system.

Ralph Pays A Visit

About a year ago, CH Precision sent around an email introducing Ralph Sorrentino, their new Brand Ambassador for America. We struck up an occasional telephone/email relationship. Since he was flying in for a dealer event in September, the opportunity to meet was at hand. He booked an extra day.

By coincidence, the timing of the event overlapped with the release of an upgrade to the CH Precision Ethernet streaming product. As we talked about it, my interest grew. "Why not install the HD Board and I'll do the first review?" I offered. Ralph then upped the ante by suggesting, "While we're at it, we could also get USB streaming going." Soon the concept for an article materialized as a comparison of three digital music front-ends: USB, Ethernet, and the silver disc itself via my CH Precision D1 transport.

This was an ambitious game-plan and I was given a shopping list to facilitate it. We would use the Roon software app for music management because its user interface and meta data presentation are considered the best in the industry. I would need to install Roon on my MacBook Pro laptop and iPhone. Music files would be stored on a 4TB WD My Book hard drive attached to the laptop via the provided USB cable.

For the USB front-end, I reconnoitered a STEALTH Audio USB cable (MSRP $850/m) to take the bit stream to my CH C1 DAC. Music served via Ethernet required a long cable from the Internet Service Provider's router to a gigabit Ethernet switch plus two short STEALTH Black Magic Ethernet cables ($1300 one-meter length) — one going to the C1, the other to the MacBook. Everything was to be hardwired; no wireless communication. I tried to keep expenses relatively equal between USB and Ethernet, however, the transport source is exponentially more costly (maybe 10 times as much for the D1 Transport and all of its cables). Both streaming configurations followed CH Precision's recommendations to create optimized signal paths.

Ralph At Work

Implementation: The New Ethernet HD Parts
When the day came, first thing I gave Ralph a brief system demo, then he set about the CH checkup. He established a temporary LAN and used the CH Control app on his Android device to check the settings of each component — all while sitting on the couch. Clever man, and most efficient. He made a list of what needed to be changed or updated.

The HD Kit

We had our work cut out for us. The C1 DAC is a modular design with slots on the back to enable various options. The Control Board plug-in was unscrewed and removed (the one with the USB Firmware update jack). The new Ethernet HD board went into that slot. Then C1 and T1 firmware updates were installed. No problems—this was easy. (Step-by-step printed instructions are included with the parts. Alternately, dealers are trained to do it for you.)

Setting up the Ethernet network was also a piece of cake, but getting Roon going for USB and Ethernet, was a bit more involved — so many options! The Roon setup benefits from an experienced hand. If I had to do this on my own, it would have taken a lot longer.

Bloom & Flow
Sometime later, Ralph announced, "OK, we're ready." He cued the first selection and Ben Webster's tenor wafted into the room (Soulville, a DSD 64 file, played over Ethernet HD).  A moment later, quite uncharacteristically, I began to laugh, long and heartily. What was this? It sure wasn't what I expected.

The next day, ruminating about that moment, it hit me. Didn't the same thing occur a year ago when the last CH digital upgrade was installed? Among other things, the CH DIG IN HD replaced the three conventional digital filters in the C1 DAC with a single new one that used a very complex, innovative algorithm. I was caught so badly off guard that I described it as follows:

With a name like HD Upgrade, what comes to mind? High Definition, of course. I assumed it would target speed and resolution — I'd probably get more page turns and chair scrapes... But the biggest difference came from so far out in left field it made me question my ears. Instead of High Def chair scrapes, I heard more air, liquidity, and continuity.

So, now we have an Ethernet HD upgrade and it pushed the sound in a similar direction as last year's DIG IN HD upgrade. Generally, when manufacturers release digital upgrades you get wider dynamic range, claims for lower noise, more speed. CH Precision releases upgrades and you get air, liquidity, and continuity. Thus the inappropriate laughter. (Please note that I did not have Ethernet streaming prior to this, so I couldn't do a direct comparison with the prior iteration. I'm purely reacting to what I hear with the Ethernet HD plug-in installed.)

Some USB Music
Like many other ensembles that were jilted by their major recording label, the San Francisco Symphony went on to establish their own, SFS Media. We are the beneficiaries. Regardless of what you think of Michael Tilson Thomas as a conductor, two things are beyond dispute:

1) the SFS is a top notch ensemble; and

2) they produce excellent recordings of audiophile quality, including SACDs, hi-res downloads, even LPs. Such is the case with their Beethoven: Cantata on the Death of Emperor Joseph II and Symphony No.2 (SFS 0058. I have it on SACD and a DSD 128 file).

In absolute terms, no system can do a large orchestra justice. The roughly 90 musicians on a stage are capable of displacing a massive amount of air. We consider ourselves lucky if it all hangs together and our miniature doesn't fall apart. When I come home, I crank up the fourth movement Allegro molto of the symphony via USB. Well, we needn't worry too much today. The USB front-end delivers excellent macro dynamics with good heft and low-end grip. It was able to grow the orchestra without signs of stress, quality was maintained from piano thru crescendo. In addition, it had wide frequency bandwidth, good dimensionality and accurate image placement. It was very clean and quiet; the total absence of artifacts and distortion took me by surprise. I dare say many CD transports would not fare as well. This was a good start as everything an audiophile wants in playback was accounted for.

To pick a few nits, in comparison to what could be, the sound wasn't the ultimate in finesse. Textures were a little coarse, I'm not hearing the inner life and timbral shadings that give instruments their unique signature, plus the atmosphere was somewhat dry.

Roon Display Of USB Path

One of Roon's nice features is the visual it gives you of all the processing steps for a file. For USB playback of Ben Webster's Soulville, it tells us the input was a DSD 64 source. Roon processed the file for the Roon Advanced Audio Transport (RAAT), followed by DSD over PCM encapsulation on the MacBook Pro platform. The file was passed to the C1 USB streaming board, then on to the C1 DAC, where it was upsampled to 705.6 kHz. Note that USB playback has the benefit of the DIG IN HD upgrade (all digital inputs use it, including Ethernet).  With USB 2.0 in use, the C1 DAC can handle PCM up to 32-bit/384kHz sampling rates and DSD up to 128 using DSD over PCM (DoP).

Some Ethernet Music
Swapping to Ethernet streaming changes the picture in a fundamental way. The noted coarseness is gone, replaced by a modicum of textures, timbres, and more low-level dynamic events. Meanwhile, you can't miss the very prominent musical flow. Air and warmth are pumped in to humidify the atmosphere, and the soundstage puffs up, especially in the well-developed depth dimension. With Ethernet, instrumental phrasings and articulation are much more persuasive, and hence pleasant to listen to. My short list of USB complaints falls by the wayside.

However, new complaints come forward. The enhanced flow seems to have been accomplished in part by transient rounding and lengthened note tails now audible as softer dynamics and less powerful macros. Part of the coarseness with USB was due to it favoring dynamic extremes; it played either forte or piano, neglecting the mid-level dynamic markings like mezzoforte and mezzopiano. Ethernet brought these back and eased up the relentless low bass, so it stopped pummeling you all the time. In actuality, dynamic range is just as wide, but it does give the impression of less slam.

Still, there is no question Ethernet streaming advanced credibility significantly and we much preferred it.

Roon display of Ethernet Path

A look at the Roon flow chart for Ethernet shows fewer layers of software processing performed by the computer. The DSD source file exits the computer and RAAT was applied by the C1 Ethernet HD board. Then it passed to the C1 DAC for conversion to ultra high density PCM. Note that CH Precision Ethernet streaming benefits from both DIG IN HD and Ethernet HD upgrades. The C1 can handle PCM files up to 32-bit/384kHz and DSD 256 over the Ethernet streaming interface.

Some Silver Disc Music
So I was feeling very good about Ethernet playback right at this point. Alas, it was a setup. When I shifted attention to the D1 transport, the balloon deflated. A funny thing happens: The transport splits the difference between the other two, cherry picks their positives and discards the negatives. I wasn't the only one who noticed that. The slam is back — transients have recovered a proper edge, note trails get their proper duration, so it's no longer soft. Plus, the flow of the music leaves nothing wanting. The view is clear-sighted with astonishing density of detail and there is no question of its accuracy. To put it in perspective, think of USB playback akin to a crisp, dry afternoon (yielding about 80% of what's to be had); Ethernet brought a warming trend with a little mist (and maybe 88%). Now the sky has cleared and there's a brilliant rainbow on the horizon (we're at 100%). I doubt digital gets much better than this.

Nota Bene
I haven't spent a lot of time with music servers, but one thing I quickly learned is that everything counts. Each part of the configuration has an impact: the DAC; the computer; the power supply in the network switch; the cables; etc. You don't escape the tweaking and fussing any more than with other front ends. Everything counts. This was dramatically proven when I replaced the $17 off-the-shelf Ethernet cables I started out with for the STEALTH Audio models. (More on these STEALTH cables coming soon.) My results are specific to the configuration in place and the percentages are likely to shift as I get in better parts.

Tips For Optimization
When I was done with music servers for the day and switched to the transport, it wasn't as good as I remembered it being. Some detective work revealed that the source of degradation was the streaming cables still attached to the DAC. For optimal results, if you're listening to CD, disconnect both streaming front-ends. If you're listening to Ethernet, make sure to disconnect the USB wire.

Conclusion
I set out to compare three digital front-ends. The impetus was the arrival of an upgraded Ethernet plug-in for the CH Precision C1 DAC. What did I learn? First, the pecking order has not changed. Music via a server has gotten better since my last audition. It's clear this is where the mass market is going, which is probably for the good. It's also clear that, for ultimate quality, you have to go with a transport. Remember: it took the CD took twenty years to become listenable. Streaming only took off around 2007. It still has a ways to go.

Second, the principal shortfalls (actually, where all digital music comes up short, even the transport) is the lack of body and continuity, or flow. That's why the last two upgrades from CH Precision gave me hope, because they delivered on exactly those fronts. Generally, when manufacturers release upgrades they claim lower noise, and improvements in dynamic range and speed. Those are not the prime issues. CH Precision is the iconoclast company moving us forward in the right direction.

Should you take the plunge at this point? My answer is a conditional YES, but only if you:

1) Can't spring for a good transport;

2) Don't want to collect CDs;

3) Want to enjoy a wide range of the latest recordings.

Manufacturers' Comments
The principle design goal for the Ethernet HD board was to have it recognized as a ROON endpoint. To do that, we quickly realized two things: it would need a lot more processing power; it would require a major software re-write.

While we were at it, we decided to implement a few other features, including the capability of the new board to draw less power, thus removing the need for it to be connected to a Power over Ethernet (PoE) switch on the network to be able to power on the C1 from the CH Control app. The board now handles files larger than 2GB and it can play back compressed DXD files and OGG files. We improved the compatibility ALAC file playback.  All of this results from the software re-write and increased processing power on the Ethernet HD board.

Regarding why the new Ethernet HD board sounds better than the USB streaming board, it could be the way each handles data errors during transmission. With Ethernet (TCP/IP protocol), if a packet arrives corrupted it is resent. With USB, if it arrives corrupted there is no re-send. Another reason may be that the Ethernet HD board implemented ROON support (specifically the Roon Advanced Audio Transport, RAAT) at the board level.  With USB, RAAT is implemented in software at the computing device level where the ROON Core is running.

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Pricing And Manufacturer
CH Precision

CH Precision
ZI Le Trési 6D
1028 Préverenges
Switzerland

Voice: +41 (0)21 701 9040
E-mail: info@ch-precision.com
Website: www.CH-Precision.com