I ordered this board from exaDevices about a month ago, and received it within a couple of days via Canadian Post. My intent was to use it with my recently completed Buffalo II build, which I’d completed (sorta) and have been using via SPDIF input fed via an Audiophilleo2/PurePower combination.

I’ve been very pleased with Audiophilleo as my USB->SPDIF converter, and having added PurePower (intelligent battery) – the exaU2I had a very high bar to clear if it was to replace Audiophilleo in my audio chain. Still, I was intrigued by the promise of USB PCM sample rates up to 384K + DSD support.

Installation was straightforward. George has well covered the handful of specifics a builder must be mindful of (wiring and supply). I’ll not get into build specifics here, as 1) they’re straight forward, and 2) well – not what I want to talk about

After tending to installation matters (I also had to shuffle components around in my case to achieve a more optimal layout with the inclusion of the exaU2I), I wired everything up and went about installing the OS X USB Drivers (2Ch and 8Ch). Installation was quick and smooth, so I chose a 44.1 song for playback. Wow. Fantastic! Next, I picked a 88.2. Again – fantastic, but once or twice during playback, the DAC lost and reacquired signal ‘lock’. Playing 96k music resulted in more sync issues, and 176k/192k files lost and reacquired lock roughly every two seconds.

Hmmm. A little digging/research, and I discovered that Buffalo II as shipped from TPA is configured such that very few (if any) external I2S boards would lock reliably at higher sample rates. Fortunately, this issue is well known and TPA provides ‘High Resolution’ firmware that relaxes the sync timing of the Sabre chip such that lock is stable with extern I2S devices.

I ordered this firmware (thanks Brian!), and installed it in my Buffalo II. I selected a 96K song – stable lock. 176k, stable lock. 192k, stable lock. 352k PCM and DSD – rock solid. Now we’re talking.

With exaU2I installed and new firmware installed in my Buffalo II, I was finally ready for some listening. If you were hoping I’d wax on in audio jargon – my apologies in advance. Such oration is not my style, nor do I find it personally useful. I’ll share my impressions, and encourage the reader to receive them (if at all) with the usual pinch of salt:

I’ve spend the last couple of weeks reading/researching other DAC’s on the market. Most of the popular ones only handle sample rates up to 192k. The few that do handle DSD playback do not handle 384/352 PCM, or cost more than I have to spend.

I ordered another exaU2I board, a Buffalo III and the other parts needed to assemble another DAC. Having heard DSD playback, I have not desire to play anything less if it’s available in DSD. I just couldn’t accept buying another DAC that didn’t provide this support, so I’ll just have to build another one. Thanks to exaDevices, I can!