I built this amp for work around 10 years ago. I use it with DIY Fostex speakers. The output transformers are from a vintage Akai 6BM8 reel-to-reel known to sound good. I had plenty of high quality parts lying around when I made this amp. It has all Allen Bradley resistors, Hexfreds, and film and Black gate capacitors. The circuit is the most basic 6BM8 using one tube for both gain and amplification in pentode mode wired point-to-point. Out of curiosity, I brought it home tonight and hooked up the speaker outputs with resistors in series to HD650 headphones playing HI-Res vinyl recordings I made through my desktop using an EMU 0404.
With speakers this amp is great; but I prefer my other tube amps. With headphones this 6BM8 amp has found its new calling. My Almarro is no longer #1 with headphones. In comparison the EMU 0404 and Tracker headphone amps just don't cut it; although their line outs sound excellent. I'm going to put a headphone socket on the front, try triode mode with the 6BM8 tubes and build a new amp for work.
Just getting started with computer audio and headphones, I'm looking forward to DIY computer and headphone Hi-Fi. I'll be asking about DIY DAC ideas soon.
Edited by Lebob - 10/28/10 at 10:18pm
