BSR “Big Knob” PA20 Conversion to 120 Watt Guitar Amp

Interesting BSR PA chassis.. came in with a number of issues and a lot of out of spec parts.. loved the aesthetic and decided to rebuild with other parts to make a 120 Watt Tiny Terror style “Big Knob” amp with a specific customer in mind.. Was a fun project and has produced a beast of an amp that can break up at low volumes when needed or can really scream loud and proud clean! Simple Gain control, tone (or rather treble cut) and master volume (Post PI). Cathodyne PI pretty Orange influenced design 2x12AX7 preamp tubes and 4x6l6GC ouput tubes.. transformers from a damaged Peavey XXX combo.. Love the style of chassis and really impressed at the total lack of hum despite everything being crammed in so close..