Exogal Comet Digital-to-Analog Converter

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Equipment report
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Digital-to-analog converters
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Exogal Comet
Exogal Comet Digital-to-Analog Converter

Digital-to-analog converters, a.k.a. DACs, continue to be one of the hottest-selling items in high-end audio, in no small part because of the increasingly widespread interest in playing music in the form of computer audio files. DACs range all over the price spectrum, from under $200 to (gasp!) $120,000 or more. Now, here’s another DAC from a new company, Exogal, which was formed in 2013 by folks formerly with Wadia. Wadia was purchased by Fine Sounds in 2011, a holding company. After the purchase, Wadia’s focus was redirected away from its former core competency of designing advanced transports and DACs. So it’s no surprise that some Wadia employees would want to continue working in the area where their passions lie. And in case you’re wondering what the heck an Exogal is, it’s a word created by combining “exo,” which means “out of,” with a shortened form of “galaxy” to denote it’s out of the galaxy. Now you know.

The first product Exogal has produced is the $2500 Comet DAC. The company offers a version with an upgraded power supply, the Comet Plus, at $3000. That puts it in the moderate price range, where it has lots of competition. So what distinguishes the Comet from other DACs in the same price range? According to Exogal CEO Jeff Haagenstad, “We had grown tired of watching the industry deliver more expensive products in more expensive cases that contained the same old tired 15-year-old technology. We didn’t want to buy that stuff at the prices our competitors were charging, and we thought others might feel that way, too. Good sound isn’t just for someone with more money than brains. We wanted to make great products that our children could afford and that delivered top-of-the-line audio performance, in a good-looking compact footprint that fits into their lives the way they want to live it. That’s why our products use smartphones as their primary remote control. Our kids are never separated from their phones! We also wanted to breathe some life back into a stodgy industry and prove that we could accomplish four goals: 1) to build great and affordable products; 2) that are profitable for a dealer to sell; 3) that are made in America; and 4) that we could pay our employees a decent wage for building. Maybe we can’t change the whole world, but maybe we can inspire people that the world can be changed, and they don’t have to accept it as it is. The founders of Exogal grew up when NASA was changing the world, and we wanted to do some of that in our own way.”

The Comet easily meets Exogal’s goal of being good-looking and compact. No one has ever accused me of having good taste, but to my eye the Comet is flaming gorgeous. Whereas some of its competitors produce DACs that are rather industrial looking (which should be no surprise—they are industrial-looking, since they were designed primarily for pro audio use), the Comet provides a high level of bling. I like bling; if I pay a high price for a piece of equipment, I want to feel pride when I show it off to others. And let’s not kid ourselves; though audiophiles may become jaded by the sky-high cost of state-of-the-art gear, for most folks $2500 is a high price. Once again illustrating that DACs don’t have to use full-size chassis, the Comet measures only 11.5" x 1.875" x 7.45". A small in-line power supply provides the juice.

Being an equipment junkie, I was curious to learn what was under the hood. What chips did the designers use? Haagenstad told me that “the Comet contains a TI PCM 4104 DAC chip for the main outputs, and a TI PCM 5122 DAC chip for the headphone output. I purposely used the word ‘contains’ because we don’t actually do a lot of ‘DAC-ing’ in these chips. We use them for final outputs but the actual ‘DAC-ing’ of the audio is done in a custom six-core DSP chip, which is all proprietary to Exogal.” This is a story that’s beginning to be more and more common: designers using innovative ways to push beyond standard off-the-shelf DAC chips to realize better sound.

The Comet’s curvaceous anodized aluminium sides and top are fastened onto an unusual base that looks like a slab of acrylic resting on four steel ball-bearings. I asked Haagenstad about the base, and he informed me that “not just the base but also the entire chassis is part of a constrained damping structure. We tried rubber feet, but they just didn’t give us what we wanted in vibration damping. I know: Go figure that rubber didn’t adequately damp the vibration, and that’s the reason. We scanned the chassis to find out where it resonated and the steel feet eliminated that last resonant frequency. Now it’s vibrationally as dead as a brick. Give it a rap with your knuckles and see.” I did and it was. Dead, I mean.

There’s a small display window (about an inch square) centered on the front of the Comet, which uses a non-illuminated LCD screen to show information about the outputs’ volume levels, the source selected, and muting status. I couldn’t read the LCD display unless I sat directly in front of it and shined a flashlight directly on the screen. I was puzzled: What’s the point of making a screen that’s so hard to read? And then there’s the remote control; it looks like something you’d hang on your car’s keychain, not a real high-end remote control. (I was afraid my cat would decide it was a toy, and it would disappear.) Then I learned the Comet is really intended to be operated remotely from an iPhone or iTouch. Android and iPad apps are coming, but in this case, there’s really not much information to display, so a smaller smartphone screen would work just as well as a tablet computer. As the smartphone apps provide all the visibility one needs, there’s really no need for an expensive screen on the Comet’s front panel. Still, would a larger, easier-to-read screen have been that much costlier?

The Comet plays PCM files with word lengths from 16 to 32 bits and sampling rates from 32kHz up to 384kHz and DSD64 and DSD128. The type of file and sampling rate are shown on the control app. The Comet is specified to operate with either Mac or Windows computers (the latter with a driver downloadable from the Exogal website), but when I tried it with the Linux-based Auralic Aries server/streamer, it worked just fine. The Exogal website has User Guides for the Comet and its SR-71 remote control device.

It’s becoming common for DACs to include circuitry that enables them to operate as the front end of simple systems, and the Comet does just that, functioning as a source selector and volume control. It’s ironic: Preamplifiers are starting to include DAC circuitry, and DACs are starting to include preamplifier circuitry. In addition to four digital inputs (AES/EBU on XLR, SPDIF on 75-ohm BNC and TosLink, and USB), the Comet has an analog input on isolated RCA jacks. The impedance of the analog input is only 1k ohm, which is extremely low; many source components may be incompatible with this impedance. For example, my Sony XDR-F1HD tuner, a relatively modern design, recommends a minimum load of 10k ohms. The Comet has a volume control, so it can drive a power amp directly via unbalanced (RCA) or balanced (XLR) outputs, or both. The output impedances of the RCA and XLR outputs are 9 ohms and 18 ohms, respectively, so the Comet should be able to drive any amplifier in existence. You can use both balanced and unbalanced outputs simultaneously, if you need to drive a power amplifier and subwoofers. Another I/O device on the rear channel is a short antenna, which sticks out the back about an inch, used to communicate with the iPhone (or whatever iDevice) that is acting as the remote control.

Of course, the Comet isn’t the whole solution to your hi-fi’s electronic needs; you’ll have to have a power amplifier to drive the speakers. Worry not. Exogal has a matching 125Wpc amplifier in development. The Ion power amplifier will only work with the Comet, since it uses its proprietary Exonet input connectors exclusively. Well, not exactly proprietary; Exonet connectors are HDMI connectors, and a standard HDMI cable is used to connect the Comet and Ion. Assuming HDMI cables can be made to sound good, it’s not really a bad idea to use them to connect components; you only have to fool with one cable per component, even for multichannel setups. (Home theaters have been using HDMI cables for years.)

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