Just finished my first build from a Boothill 5F1 kit that included a few part changes in circuit to make it a GA5 with larger transformer. The cabinet is from Guitar Cabinet Outlet on Reverb - using a 10" Weber 8A speaker. This build taught me about how a basic amp is put together and functions. The Boothill instructions are clear and it helped to compare other schematics. I deviated from instructions with the grounding (hum is quiet), kept the 1m resistor on input and eventually removed the NFB from the circuit as to reduce dampening. I'm interested in building a British 18w now.