Preamplifier/DAC Reviews

Device Type: Digital to Analog Converter/Preamplifier/Headphone Amplifier
Input: AES/EBU, S/PDIF RCA, S/PDIF Tosilnk, USB 1.1, USB 2.0, Firewire 400 (6-pin), Wordclock BNC, and unbalanced RCA (Preamp version only)
Output: (1) Pair Balanced (XLR), (1) Pair Unbalanced (RCA), (1) 1/4” headphone output, Wordclock BNC
Dimensions (H x W x D): 1.72 x 8.5 x 8.5 in.
Weight: 6 lbs.
Availability: through Authorized Dealers
Price: $1,695.00
Website: www.mytekdigital.com

Catching the DSD Buzz
The Mytek Stereo192-DSD DAC was unveiled at last year's Rocky Mountain Audio Fest right around the time of AudioStream's public launch. As we both approach our first birthday, it seems somehow appropriate that I'm finally taking a closer look and listen. Direct Stream Digital (DSD). There I said it. Most of the buzz at RMAF 2011 was the Mytek's ability to play back DSD natively and while this is truly buzz-worthy for a number of reasons, I'd say that's only about half the story.

The Mytek Stereo192-DSD DAC shows the company's Professional Audio roots in its half-rack size, AES/EBU input, and Wordclock in/out. The "Mastering Version" of the 192-DSD DAC adds a pair of BNC SDIF DSD inputs so it can act as a bridge between Pro SACD players and a computer, while the "Preamp Version" replaces those BNCs with a pair of unbalanced RCAs so you can connect a line-level source in addition to your digital audio. The "Preamp Version" comes in two flavors "Black" (the unit under review) and "Silver"; the former adds LED level meters to its black front panel which the "Silver" version removes for a cleaner and silvery look. In all other respects they are identical. We'll be talking about the "Black Preamp Version" here.

The Stereo-192 DSD DAC can handle up to 32/192 PCM playback and 64xDSD and 128xDSD through its asynchronous USB 2.0 or Firewire inputs. Native DSD playback requires two other things—custom drivers for both Mac and PC users, and a Media Player that can handle the DSD task. We'll talk more about this soon but let's cover the rest of the basics first. The USB 1.1 input is included for those Windows users who don't want to deal with loading the drivers that allow for 24/192 playback that Windows shouldn't require but it does. As noted, the 192-DSD DAC includes an input/output for an external Wordclock which I did not explore but its there for anyone so inclined. All other inputs and outputs work as you'd expect and all digital inputs can handle the full 192kHz passed through its 32 bit Sabre DAC (there are actually 4 DACs per channel in a parallel balanced configuration). You can also use any "RC5 Standard" Universal remote with the Mytek DAC (I didn't and mainly used my iPad with Apple's free Remote app to control playback).

The Mytek DAC's 1/2 rack-sized front panel is chock full of useful features. The volume knob controls volume for both the main output and headphones and when you press the "Menu" button it also controls menu navigation for playback options. These options include Input selection, Upsampling (upsamples all PCM data to 192kHz), Filters (PCM - sharp or slow rolloff, DSD - 50, 60, or 70 kilohertz cutoff), Volume Control mode (Analog, Digital, or Bypass), Volume Trim levels (-14dB to -18dB), Functions (Input, Mute, Phase, summed Mono, L-R which subtracts one channel from the other, Mid Side which combines Mono and L-R, and Dim Volume which cuts the output level by 20dB), Display (Brightness, Meters on/off, Auto-Off), Remote (Enable and Address), and Firmware (Default, and displays current version). There are two user-programmable Function buttons which can be set to control any of the aforementioned functions for quick-access, an LED Display which shows volume level and current sample rate, a Headphone jack, and On/Off switch.

The backside is equally packed and in addition to the inputs and outputs listed above, it includes an IEC power inlet so things are fairly tightly-packed. When writing for the web with no word-count limit, the temptation to ramble is practically unrestrained (not a good thing). When writing for print where size matters, having a word-count restriction forces you to edit down to the most relevant (ideally). I'd imagine choosing a half-rack size chassis enforces a similar editorial cleanliness.

If you'd like to read about the design philosophy behind the Mytek DAC as well as some highlights from Mytek's 20-year history, I highly recommend checking out "Engineering and Design of Mytek Stereo192-DSD-DAC" by Michal Jurewicz, Mytek's Founder and Principal Designer.

Mytek has also included the ability to adjust the Stereo192-DSD DAC's output gain in all models sold since March 2012. I asked Michal Jurewicz if he would explain the reasons for this option and provide output level specs for RCA and Balanced connections [see Footnote 1 for more detailed information on specs and adjusting output levels]. Here's his reply:

When I was designing the output stage of the Stereo192-DSD-DAC a variety of factors had to be included:

1) existing professional and consumer standards
2) actual large discrepancies of level sensitivities in many existing hi-fi amps and preamps that were not designed to meet these standards.
3) signal to noise ration as large as possible but without large signal distortion
4) large discrepancies of average level on existing CDs and other digital recordings, including +3dBFS max level specified for SACD DSD recordings.

When the CD standard was announced the CD founding consortium HAS NOT defined the average (0 VU) signal level for the CD the way it was earlier defined for analog recordings. Only max peak level of 0dBFS has been imposed by the nature of the medium. This proved to be a strategic mistake haunting both professionals and consumers of music until today. It has resulted in huge discrepancies of average levels on CDs (sometimes as much as 20dBs) and overuse of compression to manage that, which in turns significantly damages sound quality intended by original producer.

A high end DAC has to handle these large discrepancies well and in a practical way—a variety of levels have to be converted well without noise nor overload distortion.

Mytek has been building professional ADCs and DACs since 1992 with the majority of them designed for professional studio and mastering applications. We have gained a good level of expertise on how best to handle a variety of signal levels. Typically in a recording studio an average digital level is defined by the producers and varies from -20dBFS to -14dBFS = 0VU (=1.228VRMS on XLR line) depending on the nature of music and style of recording. For example -20dBFS would be used for live symphony orchestra, while -14dBFS would be used for analog mastering chain where levels are compressed and peak is well controlled. This -20dBFS and -14dBFS is actually the signal headroom—live classical recording requires higher headroom to handle wider dynamic range and loud peaks.

Thus the actual digital recordings vary and the DAC must handle them all very well, particularly the wide dynamic range signals more typical for audiophile quality recordings.

Connecting the 192-DSD DAC was simple and I used both USB (2.0) and Firewire to connect to my MacBook Pro and RCAs to connect the Leben CS-300XS. I ran the Mytek's volume control in Bypass mode preferring to control volume with the integrated Leben CS-300XS. I mainly used Pure Music and Audirvana Plus because both allow for native DSD playback once the Mytek drivers are installed. These drivers are located on the Mytek website so you need to download, install, and setup and there are different drivers and setup routines for USB and Firewire and they vary depending on your chosen Media Player and OS platform (Windows-users always have a few more steps to perform as compared to Mac users). I am not going to detail this process here since its simple and all you need do is follow the step-by-step instructions provided by Mytek. Other Media Players that will work with the Mytek to provide native DSD playback include Amarra, JRiver, and Signalyst HQPlayer.

Firmware updates are handled through the Firewire (FW) connection which presents some extra work if you don't already have a Firewire port on your computer. But don't fret since its easy to add Firewire through an ExpressCard or PCIe adapter. I asked Michal Jurewicz about the reasons for including a Firewire input since its not a common feature in most DACs:

If you are using current drivers off the website they [USB and Firewire] are both bit transparent and in both cases the same internal clock is used (XCO next to the DAC chip) so in terms of jitter performance they should be comparable.

Both FW and USB serve as asynchronous data pipeline, we tried NOT to have differences, even if FW is actually a better, more efficient interface that was designed for streaming while USB is kinda forced to do this.

Also USB on a typical computer has to service the DAC but also mouse, keyboard, maybe harddisk and other stuff all on the same bus requesting interrupts.

As far as why did we include both USB and Firewire, when I was designing the DAC I knew customers like choices (a given in any business) and this way we were appealing to everybody without forcing them to decide prior to buying. If someone wants FW they have it, same for USB. In addition that FW solution has an excellent on chip JET clock PLL which we use for ALL digital inputs (Weiss advertises it with their FW DACs). Having both is also redundant and covers more systems.

We were also new to the hi-fi market and wanted to make a splash. I knew we'd have to include not only great sound but more features than our competition (including DSD). I think we did manage to make this splash. I thought: let's just throw all the features at this new (for us) hi-fi customer and see what they appreciate. Fortunately, most of these extra features turned out to be appreciated.

Also, traditionally, Mytek designs (I designed about 30+ various converter models since 1992) were always about the sweet spot in high sound quality and the best bang for the buck for sound and for features. I design with this goal in mind. This is our trademark.

What's All This Fuss About Viol[ins]ence On DSD?
Let's start with the basics. In my setup with a MacBook Pro acting as front end music controller being served music from a NAS, the Firewire connection sounded better than USB with the Mytek DAC. It sounded smoother, more relaxed, more natural. This holds for DSD and PCM playback. One thing to note is you'll need a 9-Pin to 6-Pin FireWire cable and I tried a standard el-cheapo cable as well as the new FireBird-96 from Furutech ($158/1.2m) and the latter offered what I'd call better sound—less grainy and more natural. But if you take issue with the notion that a cable can make this kind of difference by all means ignore what I just said. While we're covering controversial stuff, I will also mention that the Mytek requires some break-in before it relaxes. Over the course of the first few weeks, the Mytek's sound changed considerably, going from uptight to relaxed to even more relaxed.

Regarding DSD source material, I purchased some DSD downloads including the gut-wrenchingly gripping Violin Concerto, Horn Concerto by Krzysztof Penderecki from Channel Classis. This download which features the Sinfonietta Cracovia, Krzysztof Penderecki conducting, Robert Kabara on violin, and Radovan Vlatković on horn is comprised of two tracks (41:41 and 17:30 in duration) and with my MacBook Pro's 4GB of RAM the first track refused to play through on either Pure Music or Audirvana Plus. It would stutter, skip, and eventually crash. Even with the Buffer size set to Max. So I ordered some more memory from the ever reliable www.macsales.com and slapped those minty-fresh 4.0GB + 8.0GB DIMMs into my MacBook Pro and lo and behold Penderecki played through without a hitch (w/Max Buffer size set to Max).

I also availed myself of all the free DSD downloads I could find from sites including Blue Coast Records, Channel Classis, and 2L [see Footnote 2]. Also, during the course of the review, Mytek kindly sent over a Mac Mini stuffed with DSD music so I could sample from a wider variety and all's I can say is through the Mytek DAC, native DSD playback sounds fabulous. It's important to note that we're talking about very high quality recordings but even when compared to some cream of the crop high resolution PCM, DSD had a greater sense of naturalness, frighteningly so at times especially in terms of dynamic range. This is not to say that DSD is better than PCM, it is to say that if you end up with a Mytek DAC you will enjoy some seriously marvelous-sounding DSD music.

Regular-old PCM fared very well as well especially when using the Firewire connection. The Mytek may not be the equal of the something like the Resonessence Labs Invicta in terms of overall ease and smoothness with PCM, but without the benefit of direct comparison, there's no way to know for sure. And it's my contention that since we cannot hear every DAC simultaneously, these kinds of comparisons don't matter as long as you find the Mytek completely enjoyable. And I do not hear anything in its performance that would suggest otherwise. I also tried the PCM and DSD Filters and upsampling on/off but my preferences are just that and yours may very well differ.

To put it as plainly as I know how, the Mytek Stereo192-DSD DAC is a very natural and musical-sounding DAC and completely enjoyable to listen through for both PCM and DSD music sources. Nothing stands out and apart from music's natural flow and I can and did get lost on many occasions just listening to and enjoying whatever music I cared to hear regardless of its sound quality or pedigree. I will note that I used the Mytek's PCM upsampling option (upsamples all PCM data to 192kHz) which made CD-quality source material sound, well, less like CD and more like music.

The Mytek also passed the all-important Reggae test with flying colors. What's the Reggae test? I'm glad you asked because in my experience Reggae can sound like crap when using a digital source as opposed to analog. And this crap is mainly related to conveying the beat, the rhythm in a convincing way as if digital has a difficult time getting into and keeping Reggae's sense of time (or is it also the case that digital reproduction can get lost in the details, missing the forest for the trees?). Vinyl does not exhibit this same shortcoming, at least in my experience, but something like the superb-sounding 24/192 Legend album from Bob Marley & The Wailers available from HDtracks (US) and Qobuz (EU) was conveyed in time and in tact by the Mytek DAC. Jammin'.

Subtle instrumental colors and shades did not sound the least bit bleached so the emotive quality of tone and timbral difference were conveyed in all their glory. I listened to a rip of Morton Feldman's For Philip Guston [hat ART CD 61041-4] which is slow, subtle stuff and if instrumental voices do not ring true to ones sense of true, this kind of music can make you wonder why anyone would bother listening to it for over four hours. Arthur Grumiaux performing Bach's Complete Sonatas and Partitas for Solo Violin sounded like raucous rock 'n roll (math rock?) as compared to the Feldman, and it was also presented in wonderful voice through the Mytek DAC without a hint of edginess in the upper registers.

To reiterate, when fresh out of the box, the Mytek can sound a bit strident like it's trying too hard to deliver every last bit of data but thankfully this etched sound eases and resolves itself into a natural and lovely sense of musical flow over time. Which also means the Mytek passed the "I can listen as long as I want" test with flying colors and it also passed the "I can't wait to hear _____ but I want to finish listening to this entire album first" test. When a given piece of gear sounds well-balanced, meaning nothing screams out from music's flow, I tend to smile.

And when the Mytek DAC delivered music's natural voices from well-controlled and authoritative bass to sweet and pristine-sounding highs, coupled with a convincing sense of music's unfolding time in time, I tend to smile even more because listening to music can and should be a completely pleasurable experience. With the Mytek handling my digital music library, especially with the new and exceedingly pleasant sonic surprise that is native DSD playback, I spent a lot of time listening happily, smiling.

Free Your DSD and Your PCM Will Follow
From a purely practical perspective we have to ask—how many DSD titles are out there? And the answer in wallet-terms is a lot (see this post for a list of sources as well as some other DSD-ready DACs) but in terms of a raw number of releases we're still talking less than 500 by my very rough quick count and they average around $30+ a pop. Whether or not the current catalog of titles will float your boat is an important question to ask as is how large will the DSD catalog grow in the future which is anyone's guess. But let's note that every SACD has the potential to become a DSD download.

But, and this is a big but, at the Mytek's price and given its PCM performance, especially through Firewire in my MacBook Pro setup, coupled with its ability to act as a preamp with a choice of digital or analog volume control and headphone amp, you can look at its DSD capability as a bonus. Nearly a freebee. I will also mention, mainly so people cannot point out that I didn't, it is possible to rip SACD's but this process is DIY intensive in every sense so its appeal will be for a limited few and its my feeling you already know who you are and how to do it.

To get native DSD playback, you have to do some work. Your computer has to be up to the task, Mytek recommends a minimum of 8GMB of RAM (but keep in mind one of computer audio's first rules which states - the more memory the better), you have to use one of the Media Players mentioned, and you have to download and setup some drivers. No big deal. What is a big deal is the level of performance you get from the Mytek Stereo192-DSD DAC with regular-old PCM-based music but when coupled with native DSD playback you've got one very compelling product.

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Footnote 1. I am including this in-depth description from Mytek here because it does not appear in the user manual...yet (the online version should be updated to include this information shortly). There have been a handful of cases where owners found they needed to reduce the output of the DSD DAC beyond what was offered by the "Trim Level" control to better mate with their system. Mytek introduced the "GAIN PAD" option as described below to address these cases.

Stereo192-DSD-DAC factory output is designed as follows:

XLR output DEFAULT:

Average level (0 VU) = +4dBu= 1.228 VRMS on XLR (between pin 2 and 3)
Output trim (adjustable in menu) = -18dBFS
Max output (sinewave) 9.79V RMS or 13.84V Peak or 27.69 V Peak to peak (Voltage swing)

This is the typical professional recording setting well handled by professional and some hi-fi equipment typically powered by +/-15V power rails (or larger).

It's recommended for Hi-Fi systems with well designed high headroom preamps and amps.

Output TRIM:

Output TRIM affects both XLR and RCA outputs exactly proportionally.

XLR:

Mytek DAC output can be trimmed (within the menu) in 1dB steps between -14dB and -18dB = +4dBu=1.228VRMS on XLR:

When set at -14dBFS trim the XLR out is:

Average level (0 VU) = +4dBu= 1.228 VRMS on XLR (between pin 2 and 3)
Output trim (adjustable in menu) = -14dBFS
Max output (sinewave) 6.14V RMS or 8.68V Peak or 17.37 V Peak to peak (Voltage swing)

This is the typical professional mastering setting well handled by professional and some hi-fi equipment typically powered by +/-15V power rails (or larger).

The-14dB setting results in LOWER output from the DAC. It's recommended for Hi-Fi systems which have problem handling -18dB default. -15 and -16dB trim settings are in between the two.

XLR output GAIN PAD:

GAIN PAD is a set of 4 jumpers accessible after removing the top DAC cover. The DEFAULT is Jumpers OPENED. When jumpers SHORT the pairs of pins, additional IV resistors are inserted into DAC circuit and output GAIN is Lowered by 6dB (twice in voltage terms).

PAD affects both XLR and RCA outputs exactly proportionally:

Average level (0 VU) = +4dBu= 1.228 VRMS on XLR (between pin 2 and 3)
Output trim (adjustable in menu) = -18dBFS
Max output (sinewave) 9.79V RMS or 13.84V Peak or 27.69 V Peak to peak (Voltage swing)

This is a non-typical setting intended for hi-fi equipment which cannot handle large signals well (typically powered by less than +/-15V power rails).

INSERTING THE GAIN PAD results in LOWER output from the DAC. It's recommended for Hi-Fi systems which have problems handling standard XLR levels (are distorting or are too loud).

RCA outputs:

The standard average level on consumer RCA is defined as -10dBV = 0.312 VRMS. This is pretty much implemented in most standard mass produced off-the-shelf sound equipment. This equipment typically uses lower power rails (often +/-5V) and consequently has a lower Signal to Noise Ratio than XLR equipment.

Most Hi-Fi equipment designs are hybrid—they use RCAs, but on higher voltage rails, thus capable of handling larger signals.

Mytek DAC RCA output takes advantage of this: the default RCA average output (-18dBFS trim) = 0.614 VRMS.

In most cases this level is handled well by Hi-Fi equipment and results in overall better signal performance and sound quality (as opposed to standard of -10dBV which will decrease performance).

If this level is too loud (signal is too loud or distorted) the following steps should be taken by the user:

a) GAIN PADS should be inserted - this will lower the signal by 6dB resulting in output = 0.307 RMS, pretty much within -10dBV standard

OR

b) If smaller adjustment is needed the TRIM function should be used from within the MENU.

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Footnote 2. Here are a few sources for free DSD Downloads:

Blue Coast Records
Channel Classics
DSD-Guide
2L

And for further reading on DSD, I'd recommend starting with DSD-Guide.com.

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Associated Equipment

Also on hand and in use during the Mytek Stereo192-DSD DAC review: Schiit Bitfrost DAC, AudioQuest DragonFly USB DAC.