kdawg
Well-known member
I wonder if someone could help me out. I've got a Gibson GA-35RVT amp that I've recapped, but has pretty damn low volume output. The only thing I can find is that there is weird, jumpy AC oscillation after the choke. The signal path looks strong all the way up till the tube before the output transformer, V5A.
Schematic: http://www.gibson.com/Files/schematics/GA-35RVT.jpg
Once thrown into ON from Standby, I see the oscillation on the left side of the choke, L1. Also on both sides of R39 (3.5K 7W) and R38 (5K 5W). Also on pin 1 of V5A feeding the output transformer. Both those ceramic resistors read OK, but they do look a little abused.
The choke read .022 ohms or so. Could this be a bad choke or should I replace those ceramic power resistors first? I don't have either, so I have to order them.
thanks
-kdawg
Schematic: http://www.gibson.com/Files/schematics/GA-35RVT.jpg
Once thrown into ON from Standby, I see the oscillation on the left side of the choke, L1. Also on both sides of R39 (3.5K 7W) and R38 (5K 5W). Also on pin 1 of V5A feeding the output transformer. Both those ceramic resistors read OK, but they do look a little abused.
The choke read .022 ohms or so. Could this be a bad choke or should I replace those ceramic power resistors first? I don't have either, so I have to order them.
thanks
-kdawg