Note: This is a First Listen, so take these comments as preliminary. The review process inevitably involves some learning about component matching, set-up and response to different recordings.
The Wadia 151PowerDAC effectively combines a D/A converter and a pre/power amplifier in a single very small chassis (8” x 8” x 2”). That language may be misleading though, since the Wadia 151PowerDAC doesn’t work like traditional gear. In most audio equipment, the D/A conversion is one circuit and the power amplification is another (analog) circuit. In the Wadia PowerDAC, D/A conversion is, in effect, done by the power amp. Signals are digital right up to the output stage (where they must be analog so that speakers can use them).
While this sounds like a good thing—analog having been portrayed as old school and prone to noise, and digital being the progressive approach—it isn’t as obvious as one might think. After all, as one designer puts it “what circuit design rule says that doing the D/A conversion at the output stage is optimal, given its possibly competing need to swing big voltages and deliver massive current?” I’ll leave judgment on that to our listening sessions.