I’m now a member of the Abbas DAC club. A month ago I’d never heard of Abbas.
I’ve chased digital playback trends for nearly 40 years. I bought my first CD player in 1984, added an EAD DAC in the ‘90s, jumped on the SACD/DVD-Audio bandwagon in the ‘00s, and have used hi-rez music servers/streamers for the past ten years.
I’ve always preferred vinyl for immersive listening but kept chasing digital, hoping it would catch up. At some point 120db of dynamic range and point oh oh oh oh oh oh distortion has got to sound better than dragging a rock through plastic, right?
My buddy Ron Resnick is ramping up his new system now that his listening room is ready to go. He ordered a Lampizator DAC a while back and was told to expect it in early 2023. He then bought a used Abbas DAC 2.3SE to hold him over until the Lampizator arrives. The Lampizator showed up the day before the Abbas.
I asked Ron if I could hear the Abbas DAC before he resold it, so he brought it over last week. After the first ten seconds of music, I knew I was going to buy it. After a relaxed, extended listening session, I wrote him a check.
I’ve used ESS based DACs for the past ten years (Benchmark DAC2, Oppo BPD-105D, LH Labs Geek Pulse). With a good linear power supply, the Geek Pulse sounds the best to me. But it still doesn’t sound right. To quote Frank Zappa, “the beat goes on, and I’m so wrong”.
The Abbas DAC sounds right. It’s not as quiet or resolving as the ESS DACs, but music ebbs and flows with nuance and inflection that other DACs just miss.
End of review. You can skip the rest if you're not into the digital tech stuff.
My digital playback system is as follows. An old Macbook set up in a closet runs Roon Core 1.8. A USB drive with ripped FLAC/DSF files is attached to the Mac. MacBook USB output connects to a LANrover transmitter box. The PS Audio LANrover is a two box USB reclocker/extender. Fifty feet of CAT7 network cable connect the LANrover transmitter in the closet to the LANrover receiver at my equipment rack. LANrover receiver USB output connects to a Sonore UltraDigital USB/SPDIF converter. In Roon, the UltraDigital is configured to downsample hi-rez files to 24/48 PCM. A Nordost SPDIF cable connects the UltraDigital SPDIF output to the Abbas DAC.
I did run into one playback glitch with the Abbas DAC. Fortunately it showed up pretty quickly and I was able to find a solution before I finalized the purchase. On a few familiar tracks I heard distortion that I have not hear from other DACs. The distortion is consistent whether playing the file from the network drive or streaming the track from Qobuz. Adjusting Roon/DSP Engine/Headroom Management to -4db fixed the issue.
Apparently, the SPDIF receiver in the Abbas DAC is susceptible to sample rate clipping. This is not surprising given that music files come in multiple formats and resolutions and must be sample rate converted to 24/48 PCM and transmitted as coax SPDIF to the Abbas DAC. In my experience, the clipping doesn’t happen very often, but it does happen. Roon has headroom management. Jriver has clip protection. Other playback platforms likely have a similar adjustment to fix the issue.
Russ
Update 12/31/22
Yesterday I relistened to the tracks that I initially heard distortion on when I first got the DAC. No distortion now, even with Roon headroom management turned off.
Hmmm… The distortion was definitely there when we first fired up the DAC. Ron heard it too. My guess (and this is definitely a guess) is that the tube clock needs to warm up and stabilize before the SPDIF receiver will consistently lock to the digital stream.
Hopefully this helps others who may run into this issue.
