Free Guitar Amp schematics in PDF format.
This is a low power Guitar tube amp suitable for practicing, recording or miking through a PA system. The preamp circuit and features are similar to those on a Fender Tweed era Princeton: Single Channel, Volume and Tone knobs.
The 12L8GT output tube used is pseudo exotic, but full of sweet tone. It is a dual pentode in a single bottle with an octal base. In this circuit the two sections work in parallel single ended. Gibson did something similar in a version of their Gibsonette, except they used 6V6GT.
I built mine as a head, but it could easily be built as a combo. 2W can be surprisingly loud. This is not a "bedroom amp" unless you equip your speaker with an L-pad or similar circuit. Use link below for the PDF schematic.
Almost identical circuit to the 2W amp, except output tube is a single ended EL84 (6BQ5). This is a fairly typical design that resembles entry level amps from the 1960's. Loads of tone.
Almost identical circuit to the EL84 amp, except output tube is a single ended 6V6GT. Very similar to a Fender Princeton (5F2). The biggest difference is the rectifier - the schematic is drawn with a solid state diode rectifier in place of the 5Y3 tube used in the day. Tone difference? Sure, everything sounded better back then...