I was breadboarding a two-stage 6SN7 amp, intending to use some Lundahl iron for impedance matching to 600 ohm Beyer 'phones. But I wanted to use the headphones while putting the amp together, so I tried a cheap trick: I used the output from my preamp straight to 1660 transformers to headphone jack with clipleads. Kinda goofy but sounds pretty darn good! Then I used some 1680 transformers (more inductance) instead, and thought it sounded a bit better. If you have high output from a preamp, and high impedance headphones, and have some appropriate iron, it's worth a try. For the 1660's I used the Alt Q wiring, and for the 1680 I used Alt B.
Edited by tubino - 2/11/12 at 8:44am
