FX loop/noise problems with Tremoverb amp

[Freddie WizZzard]

Just got my amp/retubed it, and I'm hearing "whistling" noises when using pedals through the efx loop. When I run everything straight to the input to the front of the amp, no whistle. Also either way I run it, I hear the occasional popping noises. What's wrong with this amp? I think it's past the window to get my money back on this amp, grr used gear. Anyone know how much techs would usually charge to diagnose/repair these types of problems?

Thanks,
-FW

 

[94Tremoverb]

Did it do this with the old tubes? If not, put them back and see if the problem goes away again. New tubes can be faulty, it may not be the amp.

What pedals are you running in the loop? Some pedals cause instability or feedback issues with the Mesa loop.

 

[Freddie WizZzard]

Didn't try these pedals w/ the old tubes. At the time that I had the old tubes in, all I had running through the loop was a Boss PS-5 Super Shifter without any issues.

I'm afraid to remove/replace the tubes again, as I had a lot of difficulty getting one of the 12AX7's into V1 due to reach/visibility issues and ended up bending the prongs and having to flex them back with needle nose pliers. It took about 2-3 tries to actually get it in there.

Pedals that were plugged in after new tubes were put in were the PS-5 Super Shifter, Boss OS-2 Dist/Overdrive, Boss CS-3 Compressor/Sustainer, and a MIJ Boss GE-7 EQ.
Tried several combinations of the pedals, with and without distortion etc.

 

[94Tremoverb]

Did you have the OS-2 in the loop? If so that's a very bad idea. If so and it was on, that would probably have made the amp unstable. All fuzzes, overdrives and distortions definitely need to go in front of the amp, never in the loop on any amp. Even the compressor is a bad idea in the loop (in my opinion). The EQ and the pitch shifter should be fine though.

V1 won't be the problem, if it's to do with the loop it will be V4 which is the one at the opposite end of the front row of tubes.

 

[cellardweller]

I'm afraid to remove/replace the tubes again, as I had a lot of difficulty getting one of the 12AX7's into V1 due to reach/visibility issues and ended up bending the prongs and having to flex them back with needle nose pliers. It took about 2-3 tries to actually get it in there.

Ewwwww...don't like the sound of that.
I'd definitely recommend swapping out V1 in that case...

get a little mirror and flashlight to aid in visibility...

If there is a crossbar on the back you might remove it...mine was just two screws holding it on...freed up the field of vision substantially!


BEST OF LUCK!