DIY tube overdrive pedal

[tunghaichuan***]

Apparently the guy builds these often, But im like you,i havent a clue with these things. Maybe one of the fellows here with better knowledge will provide some insite.Id love to see one of these things with 2 or 3 tubes in them.

That circuit is similar in concept to the BK Butler/Tubeworks Tube Driver. Since there is only a 9v supply, the tubes operate in "starved plate" mode. Preamp tubes normally operate on 100v-300v. It's similar to using a Variac on a tube amp. When there is only 9v on the anode the tube operates way outside its linear amplification range and is easy to push into distortion.

There are several overdrives similar to this one, like the Dean Markley Overlord.

If you want to roll your own BK Butler Tube Driver, there are a few threads on freestompboxes.org. PCBs, graphics, the whole enchilada.