More work on the V4B today. I've been chasing some hum and trying to figure out if it actually needs a full cap job and if it does, the best way to do it. I previously had the amp modded with a post phase inverter master. First step was to undo that mod, and see if that was a source of any of the hum. Nope. So then I went to work making some changes. First completely removed the polarity switch and any wiring behind it. The death cap is long gone. Replaced the original standby switch because it's been feeling a little loose. Cleaned up the wiring on the terminal strip behind the switches. Then I utilized the polarity switch hole to mount a pot to add a master volume back to the amp. I used the schematic from the late 70's V4 to wire the master volume and turn the slave jacks into an effects loop. As far as the hum, I swapped out a jj 12au7 in the preamp for an EHX and things got a bit better. Time for some fresh preamp tubes and then to decide about the caps. #guitar #ampeg #V4 #V4B #diy #dontelectrocuteyourself #amplifier
