... Ampeg Portaflex B12-XY? ...
1. The vibrato seems to only work on input/channel 1 and not on input/channels 2 and 3. Is this how it is supposed to be? It’s odd because channel 1 is higher gain and more crunchy while 2 & 3 are more clean lush sounding, which you would think is more ideal for the vibrato.
Yes, the
schematic (which may not exactly match your amp) shows the vibrato on one channel but not the other. Jacks 3 & 4 of the schematic feed a channel with only 2 gain stages (and no vibrato). Jacks 1 & 2 add an extra 6 gain stages to create & mix the vibrato.
I haven't played an amp with one of these circuits, but I hear it's not great at producing actual "vibrato." I haven't analyzed the circuit, but what was claimed was the circuit sought to create a lot of 2nd harmonic distortion, then wiggle
that and mix it with the original signal. Makes sense if you felt such a circuit sounded "gainy."
2. The reverb is also kind of odd in that it connects to a small external speaker. If there is room I was thinking of mounting an 8” or 10” speaker in the existing cabinet and feeding the reverb signal there instead. Does that make sense?
Certainly you can do that. Ampeg had something similar in the Echo Twin amps (except those were 2 full Rocket amps in one cab, each with their own speaker & reverb feeding the 2nd Rocket amp).
Sano also tapped signal off the main amp's speaker to drive the tank, amplified it with a small single-ended amp, and then fed reverb-only to a 8" speaker next to the main amp's 15" speaker.
3. There is a separate horn tweeter which I was thinking of removing or defeating as I don’t think all those very high frequencies are really needed for guitar. Any problems with doing that?
No problem.
Topic: Ampeg Portaflex B12-XY ?s (Read 1700 times)