Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Big chief on March 03, 2016, 09:39:50 am

Title: Fender super reverb
Post by: Big chief on March 03, 2016, 09:39:50 am

Have a squeal in the reverb when pot is turned above 3. Have replaced tubes, caps.
Any help would be great
Thanks

Title: Re: Fender super reverb
Post by: Mike_J on March 05, 2016, 05:36:59 pm

Your situation is not uncommon. Seems like the best success in eliminating the squeal is isolating the reverb jacks from the chassis and grounding them to the ground side of the bypass cap for the reverb section. It can also be caused by electrostatic noise from the power transformer entering the reverb tank. Solution I have seen mentioned is a metal cover surrounding all six sides of the tank to reflect the interference. Have heard of solutions as simple as wrapping the tank in two layers of aluminum foil or a more difficulat and expensive option of making a cover out of mu steel. Either should be placed in the vinyl bag. Location of the reverb tank can sometimes be an issue. Want to check to make sure the output jack of the reverb tank is farther away from the PT than the input is.


This issue has to have come up many times in this and other forums. I would do a search to see what other possibilities exist because those listed above are certainly not exhaustive.


Thanks
Mike

Title: Re: Fender super reverb
Post by: Big chief on March 06, 2016, 07:56:45 pm

Thank you very much

Title: Re: Fender super reverb
Post by: Colas LeGrippa on March 06, 2016, 08:42:45 pm

iHi,

check the B+ supply cap and resistor. Does the squeal goes away with the treble pot turned counterclockwise ?