Mapman wrote: "it seems USB connections seem to be much more hit or miss for really good sound than older more established and standardized interfaces designed specifically for computer audio, like TOSLINK and SPDIF. I have yet to get any clearly bad results with either of those."
Well I have. I used to mod both transports and DACs from other companies and I found lots of crappy designs. Much of the time I observed that one company would design a S/PDIF interface and the other would all copy it, even though it was a poor design. I don't believe I EVER measured one S/PDIF output circuit that was actually 75 ohms output impedance.
As for Toslink, the earlier transmitters where inherently bad, but the later 3.3V versions got better. They all add jitter. Its easy to screw these up too, like forget to put the decoupling cap close to the driver etc..
I've seen it all. None of these designers are crack digital designers with a lot of experience IMO.
Steve N.
Empirical Audio
Well I have. I used to mod both transports and DACs from other companies and I found lots of crappy designs. Much of the time I observed that one company would design a S/PDIF interface and the other would all copy it, even though it was a poor design. I don't believe I EVER measured one S/PDIF output circuit that was actually 75 ohms output impedance.
As for Toslink, the earlier transmitters where inherently bad, but the later 3.3V versions got better. They all add jitter. Its easy to screw these up too, like forget to put the decoupling cap close to the driver etc..
I've seen it all. None of these designers are crack digital designers with a lot of experience IMO.
Steve N.
Empirical Audio