Supro Jupiter - noisy Reverb

[Mars Amp Repair]

Hety folks,
This is a bit remote, but has anyone noticed any inordinate buzz on one of these amps when the reverb is 1/2 to full up? I honestly believe it's normal, but every other Supro with reverb that we have in the store is dead quiet. Unfortunately, we do not have this exact model so I can declare with any authority that it's 'Normal'.
It occurs with no instrument plugged in. Just basically noise from the reverb ckt.
I've moved wires around, tapped everything, changed tubes, etc.
My thoughts are that it's most likely circuit trace proximity, which given the relatively low volume of the buzz, is not worth trying to sus out.
Just a thought...glen

[52 Bill]

Only thing that I could suggest it to see if the output side of the reverb tank is as far away from the power transformer as possible.

[Chuck H]

That's what I would suggest. Take the tank out of the cabinet. Does the noise continue? Sometimes you can move a tank half an inch and find a quiet spot. Other times it's harder. If separating the tank from proximity to the transformers doesn't help then it may be typical of the circuit.

[Mars Amp Repair]

That's what I would suggest. Take the tank out of the cabinet. Does the noise continue? Sometimes you can move a tank half an inch and find a quiet spot. Other times it's harder. If separating the tank from proximity to the transformers doesn't help then it may be typical of the circuit.

Yup...tank is in bottom of unit far away from xformers. It doesn't matter where it's positioned w/out of cab. I figure the only way to prove this may be a design flaw, is to have an identical amp to test it by.
Thanx, glen

[Chuck H]

I can't find a schematic for this amp. I'm wondering if you've tried a different tube/s for the reverb drive/recovery? Assuming it's a tube reverb. I don't know that it is. I don't see any trend searching for reverb noise complaints for the Jupiter.

[Mars Amp Repair]

I can't find a schematic for this amp. I'm wondering if you've tried a different tube/s for the reverb drive/recovery? Assuming it's a tube reverb. I don't know that it is. I don't see any trend searching for reverb noise complaints for the Jupiter.

Yep, tubes swapped. I'm going with it's the way it is for now, at least until I can check an identical model. I work in a guitar shop, 12th Fret Music in Boise, ID and they carry Supro amps. So, at some point I'll get to check a new one to compare.
If this were a P-P wired amp, it would be a lot easier to try rerouting wires or move grounds
Thanx for the input.
g

[g1]

I don't see any trend searching for reverb noise complaints for the Jupiter.

I didn't either, but did see comments about relatively weak reverb levels, which might lead the user to turn up the reverb circuit higher.
But this seems to be about this particular model vs other models of the same brand. So Glen is fortunate enough he will be able to check another new unit at some point. That is something I miss about working in a retail shop.