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...

Quote: I know it has been 1.5+ years since that was posted, but... I think it's still timely!  Did you ever make one like this, and in any case, what would be a source for that transformer?  I've got many of the parts and tubes for something like this...      EDIT:  I stumbled on...

Quote: Hi Frank,   I recently re-discovered a neglected  ESP9 with energizer, and had a very enjoyable time listening to them last night.  I used the stock energizer with tube amps, but I'm interested in a "direct drive" DIY amp. I found the Kevin Gilmore design using 12AX7.  I see...