I have decided to resurrect this old thread because I have bought a directly coupled DIY Pass DC B1 buffer that sounds really transparent and seems to get me a sound that is both detailed and enjoyable. The kind of uncoloured sound you would expect from a passive pre.
Overall I think that the sound is a bit leaner than thorugh various valve kit I have had over the last few years, though not quite as lean as through another Pass B1 I had here briefly, but with the Pass DC B1 I certainly have better defined bass thorugh my EAR 516 and Quad ESL 57s and there is a level of realistic sweetness to the details in the presentation of most music that leaves me thoroughly impressed.
For example, I hear instrumental details in The Beatles recordings that I never heard before, and this without impairing my listening pleasure. The only thing that I am not used to is the use of the power pot beyond 12 o'clock for loud listening.
Still, the Pass DCB1 isn't truly a passive preamp, is it?