Originally Posted by laserscrape
Is passive IV + tube buffer (no gain?) your preferred choice for the PCM56?
I have been using purely passive resistor IV (no trafo) with AD1862 and it sounds so good, the SQ trade offs of passive IV with this DAC are very low compared to any other DAC ive used... this explains why the trafo also sounded so good here compared to other applications.
Yes at that time I did not find anything that would work better. I wrongly called it 'buffer', it's a 12B4 with it's gain (a low mu tube, though. & low distortion, high drive and fast.. Very much an opamp, effectively..
Today I would do it with the OPA1656. So much so that I will do a redesign and try..
There is one catch: with the tube stage I have taken advantage of eliminating the built in bias current source in the PCM63(K)..I do remember that was a real step forward.. Previously tried a bunch of bypass options in that position, nothing was comparable to the no bias..