Silverface Princeton Reverb with the drip-edge style grill. This is actually a blackface circuit though. It is a “black line” series. They are identified by the vertical black lines on the faceplate. Tremolo and reverb sound great. This thing is all original except the speaker which has been replaced with a Kendrick 10″ speaker.
Had some issues with the noise floor and also had farty, rattley bass response. Wondered if the speaker was the cause but it was not. Decreasing the V1 cathode bypass cap to 4.7uF and biasing a little cooler helped with the bass distortion (bias was set around 12W at idle with stock settings and modern, higher wall voltage which is the MAX plate dissipation for 6V6GT). However, once back in the enclosure and playing through its own speaker rather than my listening speaker it still sounded bad. The speaker baffle was rattling. Took care of that, then there was still a strange, faint ticking noise, which was coming from one of the power tubes. Didn’t hear it at first because there was a fan on close to my bench masking it. This was one of those scenarios where you fix something, realize there’s still more problems, find something else, still sounds weird for some reason, dig through it again, eliminate more extraneous noise, etc. Eventually vanquished all the demons and in the end it sounded nice.
Fender Princeton Reverb AA764 schematic