I have an attitude rather like one of my predecessor posters--I use high-quality coupling caps because I KNOW they sound better and not because I've compared them carefully. When I'm in the 5-star mood, I use TRT DynamiCaps. When I'm in the money-saving mood I use NorthCreek 'propylenes, here http://www.northcreekmusic.com/Zen.html . I use the 625V. NC Harmonys in tubed powersupplies even if I'm using D-Caps for couplers. In solidstate powersupplies I use 100V. Rel/MultiCap metalized 'propylenes and the RTS 'styrenes.

I just ordered a pair Antuique Sound Lab 805DTs, 50W. SETs. When and if I upgrade them, maybe I'll use best-I-can-find teflon-film-tin-foil V-Caps, here http://v-cap.com/tefloncapacitors.html ...maybe.

Coupling capacitors sound as different as amplifiers and at least as different as cables. If you can hear the differences among different interconnect and speaker cables, probably you can hear the differences among various good-sounding caps. Your one-channel-and-listen scheme sounds like an excellent way to find out.

Good luck.

• cap quality