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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tube Amp Help?


2002-03-12 7:46 am
Brought a pair of VTL Tiny Triodes mono tube amps about 11 years ago and I still have them but have not used them in about 2 years. I have traveled alot over the 11 years carrying the amps with me in the original padded cardboard box.
Well about 4 years ago I pick up one of the amps and hear something rattle in side. After I open the amp, which was very hard, what happen was the power supply filter Caps broke off from the thru hole pins or lugs.
Looks like the pins or lugs of the Caps were too thick to fit all the way inside the PCBs round pad holes so RTV was used to hold the caps in place. But I guess over the years the RTV dried out and peeled away and no support for the Caps. So I figure the constant traveling and transporting of the amps in the box caused the Caps pins or lugs to break away from the PCB.
I smashed each pins or lugs of the Caps (not to each other) untill each lug would fit back in the original PCB holes. First I fixed one amp (channel) at a time and when I assembled the first amp I used the second amp or channel as a guide for wiring the amp I fixed.
Okay now for my problem. One amp (channel) works fine but the other amp sounds fine at first but after 1 to 2 minutes the volume drops to a very low level as heard over that speaker. I have checked both amp visually, wiring and connections, used different speakers but I get the same result.
Anybody got an idea?
Check all your tubes are properly seated, swap them from the working amp to the non working amp, check your input jacks for corosion, attach signal to different stages in the circuit and see if you can narrow the problem down...

did you try replacing the caps? They might be faulty inside....