#248 Jul 30, 2010
I finally drew out the diagram of my preamp mixer and tone control using the paint program from windows. i saved the preamp and mixer as ssdriver1 in the steves projects photos section. The tone control and driver are ssdriver2. This can take a 5 millivolt signal and boost it to over 1 volt to drive an 18watt amp. The diodes used came from one of those 50 switching diodes packs from radio shack that I had bought a long time ago. The tone control is an adaptation of the one from max's site and i substituted transistors for the tube circuit. I made it more sensitive than it needs to be as when an electric guitar is plugged in ,with the level set to full it will drive the amp to full output with the guitar volume set to less than 1. The amp takes 1 volt to drive to 18 watts out rms and I will have to draw that diagram next. I plan to add a headphone output that does 250mw per side for 8 ohm headphones and may use lm386 chips for this. An aux out rca jack would be good too and an emitter follower circuit may be used for this to isolate it from the main amp.