If anyone is looking to build a guitar pedal, a thereimin or vintage amp from scratch and needs schematic diagrams for any pro audio gear like what musicians use, such as guitar amps, power amplifiers, vintage tube amps, effects pedals and such, check out schematics.ca . I'm a road musician and an electronics tech and have built some interesting sounding gizmos over the years. Also I got schematics for just about every piece of gear in my band from this site and they are free to download. It's always good to be prepared in case you fry something while you're on tour, which I have done. schematics-free.com has a lot of free audio schematics as well. Hope this helps!