Boba FET

A small 4 W solid-state guitar amplifier for practice and home recording: a “bedroom blaster”, not a gigging amp. It runs from an 18 V DC, 1 A centre-negative supply, and all the electronics fit on one small double-sided through-hole PCB.

The circuit. A JFET preamp feeding a very simple power amplifier. There's plenty of gain, the response feels and sounds valve-like, and the overall character leans to the “brown” sound. The tone stack is a hybrid: Marshall-style middle and treble controls, with a bass control redesigned to actually do something.