Review : Calyx DAC 24/192

Calyx got its name from a chinese poem, poetically means the corolla of music.  The brand is a division of Digital & Analog Company based out of South Korea which is a specialist supplier of Class D amplification integrated circuits, and Calyx is its recent foray in to the world of high end audio.  There are two other products available, the Kong which is a headphone DAC and The Integrated which is an amp that also sports a USB input.  I understand that Calyx is now in the process of finalizing appointment of its US and European distributors, but people can contact them direct for any inquiries.

Max mini

The Calyx DAC 24/192 is housed in a minimalistic extruded solid aluminum casing, similar to a Mac mini but some what larger and heavier.  It shouts quality and style, everything is well made and feels more expensive beyond its $1,500 price tag.  There are no buttons nor controls in the front panel of the unit, just a small LED which turns violet, indicating a signal lock.  In the back there is one set of unbalance RCA, and another balance XLR output.  Input wise, there is one single S/PDIF coaxial input and one USB.  There are two flip switches: one to select the inputs, the other to select whether you want to power the DAC with USB power, or from the included wall-wart.  The included wall wart is of generic (cheap) type and will be needed if you are driving the DAC from a CD transport, but if you feed them USB, this is optional.  

The power arrangement raised a question for me.  In other "serious" DACs, they are usually A/C to get a good power with enough juice to adequately drive pre-amps or amps.  After my time with it, I can tell you that it has more than enough power to drive a pre-amp or a power amp directly.  My understanding is that Calyx uses a "charge-pump" to store DC power in a capacitor arrays, which in turn power two  the ESS SABRE 9018 chip.  The 9018 is a 8 channel DAC, that's 8 4 DAC per mono channel phase stacked in balanced mode [Edit: Got clarifications from Calyx Audio].  Running the chips in balance mode in-theory gives superior linearity, signal to noise ratio, dynamic range, and of course - higher output (6.8v balanced output).  Given that it takes power from the USB bus, I'm assuming there are no galvanic isolation between the computer to the DAC.  So clean raw power, and a fairly low noise computer is a must, otherwise sound quality is likely to be affected.

USB implementation is of asynchronous type, which means Calyx's clock controls the data flow and is based on the new XMOS controller chipset.  The Calyx has two clocks, one for the 44.1k family and another for the 48k family - the correct way to do it.  There are no drivers needed for Mac OS X (10.6.4 or above).  For Windows there is an included Theyscon UAC2 class driver which natively supports ASIO and WDM, and in theory can go up to 400kHz (I successfully tried 192kHz).  ESS 9018 is the only DAC chip in existence (as of early 2011) that can accept true 32-bit PCM data path up to the digital conversion stage.  With some software such as Audirvana for the Mac OS, one can stream music in "integer mode" via USB to the Calyx, with full bit precision up to d/a stage.  Calyx then perform almost like an extension of the computer itself.  Please note that its S/PDIF coaxial input can accept up to 32-bit 192kHz, but I have not seen encounter a transport that is able to do that yet.

Edit Feb 24th 2011: The Calyx DAC can connect at 32/192kHz with DAC firmware release 3.1 and above for the Mac OS X.  I am able to do this with my Mac, however with the current XMOS implementation, the chip does internally truncate down to 24-bit most significant bits.  

For me, the Calyx works flawlessly.  I use a late model dedicated Mac mini music running various music player softwares, dB Audio Lab's Essential Signature USB cable to connect.  A TEAC VRDS 50 CD transport and Theta Compli Blu CD/DVD transport were also used via Illuminati D60 and Transparent signature digital coaxial cables.  The Calyx has no physical analog nor digital volume control and I listened to the it both through an Audio Note preamp, and also directly to power amps using software volume control.  Pure Music and Fidelia provides excellent dithered volume control.  Audirvana's non-dithered software volume control also works and since it's operating at 24 or 32-bit resolution you should not be too worried about throwing away bits.  Features are bare minimum - no display, no IR remote, no dedicated headphone output.  

Smooth operator

We began by listening to the Calyx DAC via its coaxial digital input replacing the Weiss DAC 202.  The Weiss was providing some of the best sounds I have ever encountered in this system, with extended 3D sound stage, natural yet detailed presentation.  With the Calyx in its place, the first thing we noticed was that it has a more laid-back balance.  The music seems to move further into the sound stage.  The Calyx sounds smoother and a bit less immediate compared to the Weiss, although it isn't soft or unfocused, the Weiss has more slam/attack.  The smoothness of the Calyx is quite deceptive, it's just as detailed and dynamic, but with a relaxed and rounder quality.  Music is refine, open and articulate but never calling attention to itself.  "Neutral" and "extended" sums up the sound of the Calyx DAC.  It's not an instantly impressive DAC - doesn't wow you with bells and whistles.  It just gives you music in a balanced and refined form.  The more I listen to the Calyx, the more apparent that I really enjoy it.  The high frequencies sound airy and open, yet with excellent detail.  Midrange is very integrated with the highs creating a realistic portrait of the music.  Bass is quite deep and full, and gives good fundamentals to music's rhythm.  However, given the relaxed presentation, it seems a bit soft on the leading edges given the illusion that it doesn't have the same weight and slam as the Weiss.  This is not to say that it is weak in the bass, which is absolutely not the case.  It has better extension than the excellent Tranquility SE DAC, for instance.  The Calyx is also dead quiet.  The background is so black that all the little low level details are rendered very clearly.  One can hear not only those details, but can also place them with precision in the sound stage.

We then moved on to USB input.  We listened in this mode mainly with the free Audirvana OS X music player feeding native, high resolution, and upsampled music files with integer mode.  We also tried Pure Music, Fidelia (1.01), and Decibel but found Audirvana's latest implementation of integer mode playback has a slight edge.  I am happy to report that computer USB playback takes the Calyx to a different level altogether.  A very good DAC is now an extraordinary DAC! 

The naturalness and tonal presentation is roughly the same, but everything becomes "bigger".  Sound stage now extends both wider and deeper, and the speakers "disappear" better than before.  There is a strong sense of involvement with ease and effortlessness.  Spatial resolution is now the best we have ever heard from any DAC - period.  With the Calyx/Mac/Audirvana trio, it is now a notch or two better than through coaxial.  The improvements were unambiguous and consistent from track to track.  We also did a comparison of Calyx USB connection to that of the Weiss 202 via firewire, and there were smaller differences between them at this point.  The Weiss's tonality is still more immediate and "live", but Calyx's spatial cues and 3D soundstage are just as impressive.  I would be as happy to live with either of them.

Ultimate computer companion?

In the quest for the ultimate digital audio playback, I find that it is no longer a single equipment that matters, it is more and more the system.  Some manufacturers such as Ayre and dB Audio Labs take the guess work out of the equation and decide for us that computers and USB is the way to go for getting the best possible sound out of their DACs.  Weiss and other pro audio makers went for firewire as their method of choice and they even published a white paper to back it up.  

For the Calyx, it is a very good S/PDIF performer in its own right, but when driven through USB from a carefully set up computer rig will give you the sound that approaching state of the digital art.  At the time of review, only a handful of DACs can connect via USB at true 32-bit (Northstar designs and M2Tech's Young comes to mind) let alone 24-bit resolution.  The point is not about high resolution music format, but rather the ability to bypass jitter-prone S/PDIF connections with native computer operating word-size that makes all the difference.  Trust me, it is not hard to hear the benefits.

Now, it boils down to a matter of personal preference whether you prefer a "neutral" or an "exciting" presentation.  If neutrality, realistic & expansive sound stage is your forte, I doubt you can find another DAC that can really better it, even at three times the price of the Calyx plus a dedicated computer.

Red: Calyx 24/192       Blue: Weiss DAC 202