As much as analogue has been a benchmark of audio reproduction for some time, you can’t deny the obvious boom in the digital market at the moment. As I type this I am using the Tidal streaming service that not only offers the latest music but also has it in a 1411kbps lossless format. This isn’t about Tidal and there are other similar options now, an example being Josh now uses Deezer, and the biggest common factor between all of them, is the ease of use. But these streaming services are no good on their own; you want a great DAC to go with… duh! Exogal are a fresh company to enter the DAC market although looking at the pedigree of the crew that worked on Comet, their first product and it is obvious the experiance is their and the team is far from new to this ball game. When Exogal designed this they said they wanted to do things differently and after using the Comet, my interpretation of that is they wanted something that like the streaming services is easy to use and neatly integrates with your current tech. Being a completely American based company the price comes in the native currency, $2500 to be precise.

Little Comets:

It isn’t the biggest device but even though the footprint maybe small, it weighs a tonne and that gives you a bit of faith in what goes on in the device. The heft is quite satisfying. The main chassis is metal with a glass plate over the top for a unique look; they even have an engraved (sort of) logo on the glass. On the front we only have a tiny screen, on the back is a plethora of inputs and outputs and then on the right side is the headphone out. While the overall build quality of the product seems strong and the metal is sturdy, the screen sits loose and was actually on the wonk when I received it and the headphone out has a plastic housed jack that is a bit rough. The back panel is much better with good quality connectors and a clear, labeled lay out, although they did choose to have all the connectors upside down? In terms of connectivity though I don’t even know where to start, we have SP/DIF BNC, Optical, USB and AES for digital inputs, all that are capable of 24/192 while USB adds 32/384 and DSD and optical is capped at 24/96. You also have an analogue RCA input but I never found a need to use that. For outputs you have both single ended RCA and balanced XLR, both of which you can control the volume of so it can act as a pre-amp. They can also be used at the same time if you so wish. You also have Exonet connectors for connecting with other Exogal products such as their upcoming amp, a serial output for future updates and controlling the comet with an automation system and a trigger output to use the Comet to turn on and off external products.

Lastly you have what could be a first for a DAC, a USB output for charging your phone or tablet, this is what I was getting at by how it integrates with the different tech you may have. What does a phone or tablet have to do with a DAC though? Well that brings us to our next point. The itsy bitsy screen on the front that has a weird metallic taint to it and can be hard to see in certain light… it is almost like they don’t want you to use it. I got CEO Jeff Haagenstad’s take on the screen.

The Display on the Comet is intentionally not that useful. It’s been our experience that you can never please anyone with the front panel displays on any product. They’re either too sparse or too busy. Not enough graphics or unintelligible hieroglyphics…. You don’t support my language…. The colors are always wrong and they’re either too bright or too dim….

Knowing this, we decided that what we really wanted was to keep people seated and listening to the music. We want people to be driven to use their smartphone apps and thus all the information available on the display and more is available on the app than on the display. Some customers look at us like we’re crazy but after living with it for a few days it turns out they like it a lot! Those big blue meters on McIntosh equipment throw off a lot of light! Future products may have different display options but on a device like this it was a very conscious decision. And I will say it was NOT for cost – this display is way more expensive than a color graphic module would have been. We took a risk.

I can fully see what he is getting at and I love that you can have it working with your phone or tablet, sitting on a sofa and being able to use it like you would a remote but also have a much clearer view of the information, rather than squinting at some brightly coloured LEDs that although may be more visible than the Comets screen can still cause you to squint from back in your listening chair. That brings me to another problem and that is the app still hasn’t seen Android release. The IOS app has been on the market for over a year now but the Android app is apparently a right pain to develop, as there is such a range of devices to individually develop it for. I am an Android boy but luckily my sister and mum have iPhone 4s. It turned out to not be so lucky as the Bluetooth capability on them phones was not good enough to work with the Comet. So what happens now? Well I get to use the included remote, which is not much bigger than an SD card, has fiddly small buttons, lag when pressed and just doesn’t feel good. If this was a music server then I can see how buying an iPad is easily justifiable for Android users but in this scenario, I think like me your going to have sit tight and suffer it until the Android app rolls around and maybe by the time you read this it will have, Jeff joked to me how even he is an Android user so I know they are going to be doing it as fast as they can.

Also rather strange is the method of feet, well what they used instead of standard feet anyway. The chassis sits upon a glass plinth, which is odd on its own but also has two rotating ball at the front middle and two further apart on the back so you can actually slide it around a surface really easy. Now I don’t really understand why this is, as once my DAC is set down, I want it to stay put but instead this rolls around when connecting cables and it becomes annoying, continually having to straighten it up.

Designed by A Team With Some Digital Know How:

If you look on the Exogal website you don’t get a lot of technical information regarding what goes on inside the DAC but fortunately Jeff gave me some insight into that. A lot of peoples first question when talking about a DAC will be what chip is used. I have never so much had that mentality, optimisation is key, hell, my current reference DAC, the Totaldac D1-Tube-mk2 that is a bucket load more than this doesn’t even use a DAC chip. Although this does still use DAC chips, the actual digital to analogue conversion happens in a custom wrote FGPA, I will let Jeff explain.

The Comet uses TI PCM5122 DAC chips for the headphone outputs and PCM 4104 DAC chips for the main outputs. We only use the final output stages of the DAC chips because all the actual “DAC” processing is done in a proprietary FPGA. We don’t talk a lot about what we actually do because we don’t really want to help our competitors copy the approach. Suffice it to say that it’s a non-traditional approach that uses a lot of signal processing approaches we learned in other industries, not just audio.

This seems great; I have had enough of the boasts over how certain DAC uses the current best chip, what is that all about. In fact I even like how they are happy to keep what goes on inside fairly quiet and just let the DACs ability do the talking, it is confident and humble in my opinion, even if the inner geek of me does like knowing exactly what is happening inside. Being that way inclined I asked for a bit more about the philosophy that went into building this DAC.

As for deeper insights into the DAC, I’ll say this much: rather than try to match the decoding clock to the original encoding clock or attempting to avoid the sync jitter issue using some sort of “femtoclock”, we actually process the digitally encoded data and reconstruct, as closely as is mathematically possible, the original signal. We do a lot of signal processing transformations on the digital data, including slope analysis, smoothing, and curve matching to rebuild the waveform in a way that’s as jitter-free as possible. It’s conceptually pretty simple but mathematically very complicated. If I meet you at a trade show or something I’ll draw it on a bar napkin but that’s as close as you’ll get to the algorithms! Jim’s background isn’t just audio but also in network processing and error correction and detection. I’m a former software engineer and I worked on DSP algorithms to dig tiny GPS signals out of relatively enormous noise floors as well as a bunch of image processing work. Jan’s done a bunch of things with digital audio, Fourier transforms, etc. When we put our heads together we realized there was another approach that no one else had ever considered so we did that. Digital audio files are quite clean, compared to the other things we’ve done so relatively-speaking, it was a piece of cake to re-render the original music.

They are doing everything their way and even if I have had some criticism so far it really is a breath of fresh air to see, it isn’t just another DAC using a Sabre chip, a run of the mill housing, a blue LED screen and a bulky remote. They want it to be more futuristic and they want the sound to be great by controlling everything from a digital domain, something I know is very complex (from my chats with Henry Audio’s Borge) but Exoxgal seem to be finding it fairly simplistic and that goes to show the brain power on board here.

Before we move onto the next section I wanted to talk about the sampling rate capabilities of this product. Now it does DSD over DOP so I set Audirvana up for it and played a bit of Dire Straits. The first thing I noticed is that the DAC showed the sampling rate as 176.4kHz even if Audirvana was telling me it was DSD. That was the first red flag. Then I listened and it just didn’t sound like native DSD, yes you can try and convince yourself DSD doesn’t sound differently but it does, its not always better but it has a distinctive sound and this just didn’t have the body or texture DSD is great for, Elton John’s Yellow Brick Road sounded better in 24/192 than it did in DSD. I let Jeff know this and he confirmed my thoughts.

The DSD support is via DSD over PCM (DoP) in both DSD64 and DSD128 formats, but not native DSD. We did a lot of market research before we settled the design details and frankly customer enthusiasm (as measured by format buying behavior) just doesn’t seem to be there for DSD. There are definite DSD believers but most listeners ultimately balk at the huge file sizes. We do have the capability to add in native DSD if there is demand but in the 14 months we’ve been on the market, not one customer has demanded it. People want to be able to listen to DSD files should they ever acquire them but it just isn’t a huge priority right now.

I will admit it, I am lucky enough to have a lot of DSD but it is more of a buzzword right now. It is obvious companies are using components just to allow native DSD and why, most people just have the few sample tracks you can download online for free. I can’t see it catching on, SACDs are barely released now days and what you can get online is only for a select group of people in terms of musical style. So if you do have DSD, this will convert it but if you want it sounding its best and have terabytes of files, this wont be ideal in that application.

Everyone Loves Headphones:

We are seeing headphone outputs on a lot more DACs these days and it makes sense as if a DAC has volume control abilities, it doesn’t take a lot to add a headphone amp stage. Now some companies simply throw it in to add a feature and it is a pile of crud while some companies such as BMC with their PureDAC spend a lot more time with it and it and the quality is on par with similar priced dedicated gear. I think what the Comet has fallen in the middle. While it clearly has had thought put into it, the overall sound quality didn’t really impress me. That being said I liked how it worked with it having a different output option so I could have the XLRs set to max volume line level output and then quickly switch to the headphone output at say, 35/100 volume. If you was to have to adjust the volume every time I can see it not being used but because of how quick you change to the headphone output it becomes much more in reach. You also had the ability to quickly reduce the volume by 20 or even mute from the remote. As Jeff mentioned earlier the headphone stage also has its own DAC, which is odd but it is of course still using that custom FGPA they have created so your still getting their intelligence in the DAC section. When I did use it I found it much more suited to lower impedance closed cans, such as the Beyerdynamic T5p and the power didn’t seem perfectly suited for harder to driver stuff. Here is the watts per channel into different headphone impedances.

600 Ohms    0.007 Watts

300 Ohms    0.015 Watts

56 Ohms    0.079 Watts

32 Ohms    0.138 Watts

16 Ohms    0.276 Watts

So while anyone serious about headphones would be much better off just pairing this with an external headphone amp as I have done, if you have a loudspeaker system and are forced to do some late night listening in quieter environments and were to plug a nice quality closed can, such as the NAD Viso HP50 or Denon D2000, into it, you would still end with very acceptable sound. That being said Exogal do intend to make a version with a much more heavy duty and high quality headphone amp section in and expect that to pop up around Q4 this year.

Sound From Another Galaxy?

It is about time we talk about the sound quality of the DAC section alone then. From my first listen with the Comet it was the soundstaging that stood out and left its mark to me. Mainly the epic width it gave me. The scale of the horizontal plane not only gave the music a lot of room to breath but also gave instruments space and distinction. However what soon became clear as well was that soundstage was so much more about width and height than it was depth and was a touch artificial in presentation. With the line out of my Lotoo Paw Gold you don’t have that width but what it does have is the depth to back it up and that gives so much more real estate for positioning instruments.  With the Lotoo the guitarist may be stood to the left but also behind the vocalist while with the Comet, he would still be clearly playing from a different position and to the left, but on the same horizontal plane.

Now originally I didn’t hear any real problem with the noisefloor and it has come of now different to the other range of DACs I have tried in the price range from the likes of NAD and BMC but during my testing of the Exogal I received the much more expensive Totaldac I previously mentioned. Is it a fair comparison? No but did allow me to find some of the shortcomings this DAC has in sonics and I couldn’t believe how much quieter the Totaldac was and I can notice an added  – interference with the Exogal. So while in its price range I find its noise floor perfectly acceptable, taking it out of its comfort zone and you do notice a chink in its armour.

Now the above testing was done with my iMac using Tidal or Audirvana, a Totaldac D1 USB cable and either the Aurorasound HEADA or Questyle CMA800R headphone amplifier. The range of headphones used was very broad but for most critical testing I used the Sennheiser HD800.

Continuing to use this set up I found a warm, easy and sometimes soft signature. Hearty bass that was bit generous on decay, clear, lush vocals that stood out and a smooth easy treble that did without the digital artifacts of ESS Sabre based DACs such as the Yulong D200 and Aurender Flow. I didn’t find there to be any stand out frequency ranges although the upper mids did seem a little bit edgy at times, trying to push forward but being strained at the same time. That little strain keeps these from ever being fatiguing though. This is a relaxed DAC, never hard on the ears and plenty of natural details on display. The bass seemed smooth and warm in the mid bass, a little extra decay taking away from the hardest hitting bass and sometimes extension didn’t seem absolute. Because of this you get a very natural reproduction of the low frequencies, especially in the mid bass. The treble seemed to be a great hybrid between delta sigma DACs and non oversampling models. It had the great extension and air and just a touch of shimmer from the delta sigma based units and yet it also was smooth not in your face. No it wasn’t as effortless as a NOS DAC but it had some of the mannerisms.

Now I did take it to Josh’s for a go in the speaker room as well and using an Astell & Kern AK240 as an optical transport, a Symphonic Line Intergrated and some Amphion Argon 1 stand mount speakers and this did present a shortcoming I was unsure of from simply testing headphones with it and that was its ability to present big macro details. Sometimes it sounded just a bit weak. Yes it was resolving but it wasn’t hitting as hard as I like at times, it didn’t have the power. It was just a little bit too chilled out.

Sonically the DAC is efficient and for those who want a relaxed and un-fatiguing sound they will likely find happiness hear. The Bottom end could have a bit more extension, the soundstage could do with some depth and the dynamics could be improved. On the flip you get easy details, not in an extremely revealing sense but in a not forced manner, smooth treble and a really wide and focused sound.

Blast Off:

I like Exogals approach, not everything was a hit with me and some things I did scratch my head over but I still have full respect for them sticking to their vision and not just making something completely generic. The sound, while not perfect, shows that their understanding of digital sound processing is pretty impressive and for those future prepared folks, this may just integrate with your current tech just right.

Sonny Trigg