Video of hum noise when I switch on the reverb of my Twin Amp

[tochiro]

Hi,

Here is a video of me switching on and off the reverb of my Twin Amp:



The hum gets louder when I turn up the reverb. In my video, the reverb was at 6 (of 10 graduations) and all volume at 0. The hum remains the same if I disconnect the footswitch.

The amp is only 4 years old and in very good condition, tubes are new and correctly biased, apart from the noise the reverb is working normally.

I checked the reverb cables and they are ok.

I should add that the tremolo is producing the same kind of hum with the modulation on top of it.

Do you experience the same problem?

Thank you.

 

[StompBoxBlues]

For any experts here with some good ideas, just thought to mention the counterpart to this thread is also in the plain "amp forum", with more info...

https://www.thegearpage.net/board/index.php?threads/660419

Just mentioning so the same old questions/answers don't get asked.

 

[tochiro]

Thank you StompBoxBlues

 

[JerryP]

Unplug the reverb tank and see what happens.
Jerry

 

[donnyjaguar]

Move the line cord away from the reverb tank leads?

 

[tochiro]

If I unplug the reverb tank, the hum remains the same and another noise is added on top of it. donnyjaguar, what do you mean by the line cord?

 

[donnyjaguar]

On one of my Fenders if the AC cord is anywhere near the leads to and from the reverb pan, or the pan itself for that matter, the reverb hums.

 

[tochiro]

I've just put the AC cord as far as I could but to no avail unfortunately. Thanks anyway.

 

[donnyjaguar]

Take the reverb return lead off and short the contacts together. Now power up and see if the hum is still there. If so, the problem is inside the amplifier. If not, its a problem with the pan or leads only.

 

[Jeff Gehring]

I'd suspect the solid state stuff may have let you down. Those op amps in the reverb and trem mute circuits; also check the + and - 16v supplies to make sure they haven't crapped out.
Jeff