Ultra Class A Superdrive Power Amp

Tim Escobedo has published what is arguably one of the coolest collections of circuits available for guitar effects. Among these is the Ultra Class A Superdrive Power Amp *Signature Series*.

This little wonder puts out such a small amount of power that you can barely hear it through a cab. But put a fuzz or boost in front of it and it is actually useful. Here's the schematic (note that this is iFramed directly from Tim's site--I'm not reproducing or hosting any one else's schemes on beavisaudio.com:)

I had the parts in my bins so I decided it would fun to build. And to do it in the smallest possible enclosure.

So far, so good. Even the battery fits in there.

I also wanted to mount the transformer and transistor on the top of the case to make it look like a little amp. After a bit of playing, I recalled Behringer's fantastic valve enhancement technology wherein they place a small amber led behind the 12AX7 starved-plate tubes to give the illusion of a glowing valve.

Aha! What if I mount the transistor in a hollowed out 12A*7 tube and stick a LED behind it? Pointless gimmickry or ground-breaking sonic advancement--you be the judge.

Ok enough with the singular wit and banter. The completed amp:

And just to prove that the tube actually does glow:

Clips

Heh. Clips. It sounds pretty junky. You don't want to hear clips.