This is one of those discussions where there is no right general answer only individual taste. I'll briefly share my experience. A friend of mine has an MSB Analog DAC with the preamp/volume module. Awesome DAC by the way. I played it by-passing my ARC Ref 10 preamp and using the ARC by-passing the MSB pre. What struck me first was the difference between the two set-ups. I have always believed and also experiened the adage that "the pre is where all the damage is done." The MSB Analog pre section is very good. Wide soundstage and excellent resolution, particualry on the lower octaves. However, it could not match the depth, detail, blume and densness of the ARC. Also the ARC just made subtlties and nuances clearly more real. Lastly, as one would expect, there was more air around everything with the ARC. So my taste favoured running the source signal through a very good pre.
Ray
Ray