Exogal Comet DAC
Inputs: AES/EBU on XLR, SPDIF on 75Ohm BNC, Toslink, USB-B, Analog on isolated RCA
Outputs: One Pair Balanced (XLR), One Pair Unbalanced (RCA), 1/4" headphone jack
Dimensions: 1.875 x 7.45 x 11.5 in., (47.6 x 190 x 292 mm)
Weight: 9.2 lbs (4.2 kg)
Availability: through Authorized Dealers
Out Of This Galaxy
Exo (out of this) + gal (galaxy). Exogal came to Earth in 2013, formed by four audio industry veterans, Jim Kinne, Larry Jacoby, Jeff Haagenstad, and Jan Larsen, "who worked for the some of the biggest names in the industry." From Exogal, "Jim Kinne is the technical heart and soul of Exogal. He’s a legendary audio engineer who’s produced countless award-winning products in his career, including the Wadia 27 decoding computer, Wadia 270 CD transport and the Wadia 790 PowerDAC, to name a few." Exogal currently has three products that include the Comet DAC, the Ion Digital Amplifier, and the Comet Upgraded Power Supply. Today we'll be probing the Comet DAC.
The Comet will play up to 32/384 and DSD128 via USB. It also offers AES (32/192), S/PDIF (32/192), and Toslink (32/96) inputs as well as an analog RCA pair all located on the unit's backside. Outputs include both balanced XLRs and single-ended RCA pairs. Finishing off the back panel is the inlet for the included power cord. There's also a 1/4" headphone jack on the unit's right side. Up front is the display which shows the selected input, the output (headphones or "Main"), volume level, Mute status, and the current track's sample rate for a few seconds. As you can see from the pictures, the display is a very low contrast tone on tone deal which makes it only visible from close range. Since the Comet includes a digital volume control, you can use it as a preamp as well.
The anodized aluminum chassis comes in silver and black and the entire package is relatively small, uncluttered, and attractive to my eyes with its shiny black top plate and the outer space Exogal logo. You may have noticed there is no power button on the Comet but you can turn the unit on/off with the Exogal app although the company recommends leaving the unit powered on for best sonic results.
I asked my contact at Exogal about the D to A process employed in the Comet. Part of the response I received from Jeff Haagenstad, Exogal's CEO, is worth repeating here:
The short answer to your question is "No, we won't provide answers to the questions about How We Do It."The Comet converts DSD to PCM internally (DSD64 converts to 176.4kHz and DSD128 converts to 352.8kHz) as part of the D/A process so those insisting on "native DSD" playback will have to look elsewhere. To my mind, it's all in the implementation and accompanying musical output that counts and we'll be taking a listen to some DSD files shortly. Exogal also talks about upsampling in the Comet manual, "EXOGAL’s digital filtering algorithm produces a higher resolution digital signal than the 16 bits stored on the CD. This high-resolution signal is then used in the computations which in turn reduce the volume level. This new signal is fed directly to the DAC chips. Through this innovative method, the EXOGAL Comet maintains high resolution even at the lowest volume control settings."
The longer version is that we don't do our D to A conversion in a conventional way. We have implemented a 6-core DSP in an FPGA (and we blew the "Read" bit, so we can write to it for upgrades but it can't be read or decompiled...) and we use some signal processing approaches that are unconventional in audio but not in wider signal processing work. We wanted to pursue patents but since it's all based on other algorithmic approaches there was too much prior art for us to do the patents. Hence the need to keep it Trade Secret.
If you look at our backgrounds, you'll see that in addition to audio experience, Jim worked on some broadband networking technologies, I've worked on GPS, Vehicle Guidance and Computer Imaging applications, and Jan has a bunch of different signal processing experience. We have all worked in applications with harsh and unforgiving computational environments so converting a relatively clean PCM signal to analog audio is actually a fairly simple thing for us to do. (Conceptually, if not mathematically)... The EXOGAL DSP platform (on which the Comet is the first of many products to exploit the technology) does have some conventional DAC chips but only the final output stages of the DAC chips are used for the final translation into analog. The main output uses PCM4104 DAC's and the headphones use PCM5122 DAC's. The outputs are buffered using TI/National LME49600 buffers. These are high-current, high-impedance, class AB buffers with no feedback. Beyond that, we ain't sayin'.
The Comet comes with a tiny hand held remote which allows input and output selection, volume up/down, and mute functions. There's also an Exogal Remote app for iOS and Android devices offering these same functions. I found the app to be easier to use with my iPhone as the remote really is pretty tiny. I also have a thing about remotes, namely I don't care for plastic. But that's just me. Exogal offers a power supply upgrade for the Comet but I did not try it for this review.
Outta This World!
I'm not going to sugarcoat this: the Exogal Comet DAC is one fine sounding piece of technology. If you sit and listen to the Comet, over time, you will hear what sounds to me to be a very natural and highly involving musically engaging DAC.
I listened to the Exogal's USB input since it alone can handle DSD. Using a length of Light Harmonic Lightspeed cable connected my MacBook Pro running Audirvana and Pure Music, I played all manner of music through the Comet over a number of weeks. More than most DACs that have come through here, I also believe the overall sound of the Comet relaxed and improved over time. I would not judge a Comet cold.
Another reason I say you should listen to the Comet over time is because it doesn't really jump out at you and announce itself in any obvious way. While it is very resolving, it is not highly resolving like some other DACs including the Mytek Stereo192-DSD DAC. While the Comet delivers a goodly amount of tone color and has an overall sweet sounding disposition, it is not as vibrant and sparkly as the Auralic Vega. If anything, I found that the Comet leans toward the softer, smoother side of the presentation without sacrificing, well, much of anything. The Comet is subtly damn musical.
I know we've been talking a lot about high-res music lately mainly because of Neil Young, marketing, and the mainstream press' inability to hire experienced writers, but I really think people either make too much noise or not enough noise over the differences between CD-quality and high-res. Don't get me wrong, when there's a high-res version of music I'm interested in I usually buy it, but I do not buy music because it is high-res. Get it? I also do not re-buy a lot of the same music because I have a limited budget and I really enjoy new music. Besides, CD-quality can sound simply stunning and the Comet DAC delivers excellent results with such material.
I played the crap out of the lovely self-titled Ibeyi CD-quality album and its sounds, rhythms, and rhymes were purely delectable through the Comet. There's plenty of delicacy, detail, and dynamic drive in the music and to the Comet's presentation so you feel very connected to the music at hand. I dare say there's an analog-like ease here which is something I have not heard from a DAC in the Comet's price range. While $2500 isn't chump change, you are getting a lot of musicality for your money. Tidal's lossless streaming service also got a fair amount of play time through the Comet and I am continually thrilled with Tidal's growing music library as well as it's audio quality.
I ran the Comet into my Pass INT-30A at a fixed full output level as well as variable out using its internal volume control. Not only did I not hear any negative impact using the Comet's volume, I actually preferred its sound. I know, I was surprised too. I also listened to the Comet's headphone output with the NAD HP50s and was greeted with equally compelling sound.
I also played a number of DSD recordings including the lovely Vivaldi - La Stravaganza /12 Violin Concertos (DSD64, Channel Classics) which is a native DSD recording and guess what? It sounded lovely. Airy, fluid, and spacious. Ellington's Indigos (DSD128, High Resolution Tape Transfers) was also presented in all its silky smoothness and a very solid and dimensional sound image. Again, the Comet does not seem to emphasize any one aspect of music reproduction. Rather, it strikes me as delivering a well-balanced musical portrait.
Just for fun, I hooked up the Audioengine B1 Bluetooth Receiver (see review) to the Comet's Toslink input and streamed some tunes from my iPhone via Bluetooth. As I mentioned in my Audioengine review, the Comet delivered a more engaging and generally a more musical sound as compared to the B1's internal DAC.
What's wrong with the Comet? I can see how some people might not be drawn in by the Comet's strengths which are as I said subtle. It may just not be boisterous enough sounding for some people, in some systems. I've also heard more in some sonic categories including bass response, dynamics, and even more tonal saturation but in my experience you are going to have to pay more to get these extras while keeping the Comet's standard sound equipment. Impressive.
A Rising Comet
As a first product out of the gate for a new company, the Exogal Comet is a rising star. The Comet delivers more than its fair share of the musical message and is very capable of keeping you connected to your music over time. Highly recommended.
Also in-use during the Exogal Comet review: Auralic Vega, Mytek Stereo192-DSD DAC