clicking on the title of this post will send you to a download page for the book SOLID STATE GUITAR AMPLIFIERS by TEEMU KYTTALA. trust me, DON'T be dissuaded by the title! even though sold state amps are kind of like kryptonite to many tone whores, this book contains tons of info that can be extremely useful when designing audio circuits. explicitly the preamp section, which is full of heaps of goodies that can be used for stompbox design. it's written in a simple, yet concise style that tells you just what you need without getting bogged down by too many details. also, the power supply and power amp sections have everything that you would need to build an ss amp. this book really is a great resource that i will be diving into head first. i believe teemu goes by teemuk on the forums, so make sure you give him a hearty thank you if you download the book!