mr_bill - are you asking if the volume through the digital output is good vs the volume through the RCA's?
I have used the stock SB3 in two configs - one was out the digital coax feeding my old DAC (a Bolder Mensa), and then on to an integrated amp. The other config was using the SB3 analog outputs, directly to drive a gainclone amp I have.
I liked the sound of the stock SB3 enough to sell off my DAC, and a pre I had, and a few other cables etc.
I have had my SB3 fully modded, and intend to use it out the analog RCA's going forward.
Now, I have never had the chance to try the SB3 out the digital coax, into a DAC, and THEN direct to an amp, leveraging the digital volume control, but I have seen others suggest that this is not the best approach.
From what I gathered during my research, folks using the analog outs are using them directly to feed a power amp, and folks using the digital outs, are feeding a DAC, and then to a pre, then onto an amp.
Just one guy's experience and thoughts,