I just got a SB3 before Christmas, with the RWA analog output mods. Those mods may have been a waste, I connected my AS NOS Dac to the SB3, and they sound really good together. And, I am still using the el cheapo stock SB3 walwart. The SB3 analog section still needs to break in, but right now it lags behind the AS dac.
I plan to make some mods to the digital out section of the SB3, and see how good it can sound. I am already REALLY happy with the combination. I had been using a USB DAC to feed my AS Dac, and I just thought the Dac was OK, guess it was garbage in, garbage out.
I am also thinking about making some dac upgrades that Peter recommends, but the 4 power supply caps (black gate N's) will cost $240, and the Vcaps Peter likes for the output coupling caps would cost $350 for a pair. I could try the sonicaps teflons instead, that would ONLY be $150 a pair, for 1uf for the output caps. Since Peter already uses very high quality parts, it costs a lot to upgrade, and I don't have the budget right now.
Randy