Challenger CH18 Modified PA Amplifier - Late 40s

Modified Challenger CH18 amplifier with original tubes: Preamp: 6SF5 + 6SJ7 + 6SL7 Power: 6v6GT (x2) Rectifier: 5Y3 I modified this amp to have a Baxandall tone circuit and added a screen bypass cap (.01 µF to ground from pin 6 on the 6SJ7) on a switch to increase the gain. Presented as a variety of tone options with knob positions as follows: -Gain switch off- Bright Clean: Volume 30, Bass 50, Treble 100 Clean: Volume 50, Bass 50, Treble 75 Edge of Breakup: Volume 75, Bass 50, Treble 75 Crunch: Volume 100, Bass 50, Treble 75 -Gain switch on- Blues: Volume 30, Bass 50, Treble 75 Hard Crunch: Volume 50, Bass 50, Treble 75 Drive: Volume 75, Bass 50, Treble 75 Cranked: Volume 100, Bass 50, Treble 75 Run through the 16ohm output into a Marshall 4x12 with Celestion G12T-75 speakers. Captured with an SM57 at the edge of the lower left speaker and an SM58 on the center of the lower right speaker. I captured both mics plus a blend for all tones but only kept the best examples of each for sharing here. Most of these captures are using the SM58. Signal chain: Focusrite Scarlett 2i2 > Palmer Trave > CH18> Marshall 4x12 > SM57/SM58 > Scarlett 2i2