ESS Sabre Reference Audio DAC
When I first received an email from ESS announcing a new DAC, I assumed someone had revived the old Electro Static Sound, but I was wrong.
"We've been making semiconductors since 1984," sales and marketing VP Robert Wong told me. "We started out making voice chips for talking dolls and toys, then got heavily into chips for soundcards and games, and eventually made chips for cell phones and CD video players. However, we are totally committed to quality and the competition is increasingly price-based for components that are 'almost as good.' We don't do almost as good. We make instrument grade parts."
Enter Martin Mallinson, an engineer who had put in years designing ICs for Analog Devices. Mallinson had an idea for a completely new kind of DSD/PCM DAC the company has dubbed the Sabre Audio DAC.
It can provide eight channels of high-quaity surround sound or two channels of exceptionally high quality stereo sound. "Each time you double-up the channels, you drop S/N," Mallinson said. "So you gain a 6dB drop in noise running this in stereo mode, giving us a measured 134dB dynamic range, -118dB THD from 44.1kHz to 192kHz sample rates.
So, what's different about the Sabre? "It's not a Delta Sigma converter," insisted Mallinson. "Actually, without ESS's Hyperstream modulator and Dynamic Matching, it tests slightly better than a Delta Sigma design. Tricky, that—I can measure differences between them, but listening tests revealed there to not be such a big difference.
"But when we added in the Hyperstream Modulator, which noise shapes and cascades independently stabilized lower-order modulators to achieve a nominal 90% modulation depth. It also employs a time domain interpolation algorithm to render the data into a higher clock domain without polyphase filters."
Mallinson paused, then added, "We found if we turned off two components of the DAC, listening tests revealed that it sounded 'worse,' which is to say identical to high-quality Delta Sigma converters. I'd ask the trained listeners what they were listening for, and they just said, 'it sounds better.' I was hoping they'd give me an answer I could measure for."
Mallinson sat me down to listen to a breadboarded DAC fed by a fairly standard transport. I handed him Pipes Rhode Island and asked him to play Howells' "MAster Tallis' Testament." I was struck by the clarity of the harmonic trumpet swells, but noticed Mallinson figeting behind me. Then it struck me. "That's not distortion, that's air spill from the organ pipes—it's a detail I listen for."
Everyone in the room relaxed. Me too. The music was good.
The Sabre DAC is available to manufacturers in three levels of quality: Reference, Ultra, and Premier. Interested manufacturers should go to www.esstech.com.