Antelope Audio: Pure2 master AD/DA converter & clock

Jessica Thompson: When it comes to A/D conversion, my number one desire is sonic invisibility. Especially when I'm in the middle of a long-term archiving project, I don't need "flavors" of conversion. I want neutral, accurate conversion; three-dimensional lows and mids; and phase-coherent, soaring highs. (Don't we all!) Because I'm working with archival formats, I also need flexibility in both connectivity and calibration. 

I kept the Antelope Audio Pure2 demo unit in its box for way longer than I should have, not because I was unenthusiastic about trying it out, but because I was avoiding the anticipated downtime associated with integrating new gear. I'm happy to report that when I finally pulled the unit out for review, setting up took me all of 15 minutes, start to finish. I plugged it in, attached it to my Mac via USB, downloaded the Pure2 Control Panel from the Antelope Audio website (for Windows 7.1 and higher, or Mac OS 10.9 and higher — dang, can't use it with my old laptop at home!), clicked a few buttons in my Mac's System Preferences, plugged in a pair of AES cables, and started converting. That's a true testament to ease of use. 

The Pure2 utilizes Antelope's Acoustically Focused Clocking (AFC) technology and builds on the Eclipse 384 high-end converter [Tape Op #96], integrating these technologies into a sort of "best of" unit — a high quality, incredibly flexible, yet still affordable two-channel converter. With eight word-clock outputs, this could be the master clock for your entire studio. 

While I get the benefits of running tones and performing null tests, what I really want to know is how the gear sounds in real world applications; so I put the Pure2 directly to work digitizing different analog and digital media. First, I digitized a cassette of a live concert recorded in 1987, setting up the Pure2 at its maximum 24-bit, 192 kHz bitrate. Sometimes with historic audio, it's hard to gauge A/D quality because the signal-to-noise ratio is already impacted by media format, age, and condition. I transferred this same cassette using my Mytek 192 ADDA, so I could do a shootout. At first, I felt the Pure2 left this cassette recording a little flat, so I fiddled with the settings on the control panel and was able to dial in a better input level, which helped dramatically. The noise floor dropped, and the music sounded fuller from top to bottom, like I was finally getting the most out of my 24 bits. 

This flexibility has its upsides and downsides. You can use the Pure2 as a set-it-and-forget-it A/D unit, and it will do its job well. Or you can tweak the settings for each usage and make this constant optimization of input levels part of your workflow. A little more work; but lower noise floor and thus superior results. 

Fortunately, the Pure2 is easily configurable from the front panel or the software interface, thus ending my days of crawling on the floor with a tiny screwdriver to recalibrate my Mytek. Saving the presets was a bonus! I could digitize a batch of cassettes at -14 dBFS, then hook up a MiniDisc player (oh yes, we're preserving MiniDiscs now!) via S/PDIF and create a quality preservation copy. Then I could connect the Pure2 to the AES outputs of my Vadlyd Archival Phono Preamp, bump the input to -12 dBFS or even -9 dBFS, and capture perfect level off an old LP — not so hot it clips, but loud enough to minimize the noise floor. 

How did the Pure2 sound? I've heard converters that sound richer and more dimensional but cost ten times as much. And I've heard converters that sounded duller and smearier that cost the same or more. In my trial usage, which, to be fair, was focused on A/D conversion only, the Pure2 was a solid performer. Given its price of just under $2200 street and its incredible flexibility and functionality, the Pure2 is an excellent option for mastering and archiving studios. And — major caveat! — I did not link it to the amazing Antelope 10M rubidium atomic clock, which I have heard in action [Tape Op #68]. I can only guess that the Pure2 is a true knockout with the power of the 10M's clocking. 

Sarah Register: I feel pre-destined to like gear from Antelope Audio. I'm not sure if it's solely because of good experiences in the past with the 10M rubidium clock, or because I'm drawn to Antelope's clean and sleek designs — or possibly something even more amorphous. But over the weeks that I've been considering this review, I've been searching for something critical to say about the Pure2 (either paired with the 10M or not). I'm coming up blank. I've been almost exclusively focusing on D/A conversion, and I'm appreciating it on all different types of music. The subtle differences when pairing the Pure2 with the 10M are remarkable, although remarkable in an extremely minutia-type way. That said, I also found the Pure2 very pleasing when flying solo as a master clock, as well as similarly remarkable when locked to the MUTEC MC-3+ clock [Tape Op #106]. 

Ease of use of the Pure2 is top notch, and two "hidden" menus offer easy access to everything you'd want to get nitty gritty with. What I consistently heard was remarkably clean and clear playback that didn't feel "hyped" in any notable area. It's curious that I'm almost expecting a converter to have an identifiable "sound," and maybe, if anything, that's a small discredit to this unit. I can't put a finger on anything and say "the material feels more xyz because of the interaction with this converter," but even that comment is on shaky ground, because the potential for relying on the Pure2's transparency is of significant value. I'm a fan. 

Chris Koltay: I remember the first time I got a real stereo. I put on all my favorite records and initially felt disconnected from them. I was so used to my old stereo that I thought my old one sounded better. Then as my ears adjusted to the new sonics, I realized I had never really heard Pink Floyd's The Dark Side of the Moon! This is a sensation that has repeated itself throughout my career as an engineer. Anytime a piece of crucial gear is replaced, I go through this same adjustment period. I plan for it now and actually look forward to it. Some of you will remember a review I took part in for the Antelope Audio Orion32 AD/DA converter [Tape Op #99]. This was one such instance. Another was the switch from my trusty Sony 

MXP-3000 to the Rascal Audio ToneBuss [#71] for mixing. Recently, the rad folks at Antelope Audio sent me a Pure2 to demo. This is another example of the above phenomena — in a profound way. 

The Pure2 seems designed for mastering folks. It's super- high-resolution audio path and clocking options are, as with all Antelope gear, top-shelf. The software Control Panel is super easy and beyond intuitive. As usual with newly acquired gear, my Pure2 was installed about 10 minutes before a mixing session. Local/global heroes at Jumperz <www.jumperzaudio.com> sorted me out with the necessary cabling to integrate the Pure2 into my MXP-3000's patchbay. The Pure2 is so easy to set up, and it works seamlessly with other Antelope gear or on its own. My main configuration for this review was the Orion32 sending stems from my DAW to the ToneBuss to the Pure2. The mix was then communicated into the DAW via the Orion32 using S/PDIF from the Pure2. Both the Orion32 and Pure2 were locked to the 10M. The routing was a snap, thanks to Antelope's Control Panel software. 

So my first impression listening was that I noticed a drastic improvement in imaging width and heard flat-black low-end that seemed to extend my speakers' range nearly an octave down. The top-end had similar extension. It sounded like an invisible glass ceiling above the limits of human- hearing was removed, revealing some errors in placement and over EQ'ing of elements in my mix. When starting from scratch, mixes were completed much more quickly, and the amount of sonic real-estate at hand seemed close to limitless. All of this contributed to the aforementioned sensation. I really loved some things about existing mixes, and I became more aware of some sloppiness. It took me a minute to really understand what the Pure2 was doing. Basically, I had to put a stop to a bunch of dumb shit I'd been doing mix-wise, and get out of the way of the material to let the Pure2 do its thing. Like most engineers, I get stuck in ruts despite efforts not to. The Pure2 pulled me out of a few. It's as if it demanded better from me. Criticism is hard to swallow from a human; from a piece of hardware, it's downright offensive — until you get over your pride and realize the truth. This, combined with the sheer ease of use, made the Pure2 a must-have for me. 

Worth mentioning is the monitor controller page in the Pure2 software. It allows the user to control speakers and a headphone amp, as well as the I/O. As I become more familiar with the individual units in the Antelope Audio line, I realize they are all designed to work together. You can have a fully-functioning 32-channel studio in very few rackspaces! Another amazing feature of the Pure2 is that it works well in a portable recording rig. All you need is a USB cable and a laptop, and you can capture stereo audio at 192 kHz! I ran a few mixes this way, and the results were downright breathtaking. With all the control the apps provide via the presets, toggling back and forth took minutes. 

It's refreshing to work on gear that evolves as you do. I figure out some new workflow and think I'm a genius, and then I realize the people at Antelope Audio were way ahead of me.