06-11-08: Macrojack
"Rowland Capri SS preamp into Audio Mirror tubed power amps into Zu speakers turned up to 95 on the preamp scale causes a barely audible hiss with my ear about 2 inches away from the tweeter."
I've got the Rowland Continuum 500 SS integrated amp, where both the pre-amp (same circuit as the Carpir)and amplifier section (same as the Rowland 501s) both operate in DC. (Power Factor Correction converts any AC to 385V DC). I'm impressed that your tube amp gets so very close in terms of quietness. That's excellent. I hear about the same on my all-SS integrated.
BTW, I generally listen at a setting between 50 (when it's very quiet and I'm reading with music in the background) to 80-ish (when I'm trying to blow myself out of the listening seat with Mahler's 6th). At any of these levels I can't hear anything out of my tweeter.
Dave