Trouble shooting Silvertone twin twelve, squeal

[music*child]

Hi, I am new to the forums and have recently purchased a silvertone 1484 twin twelve.

The problem is there is a high pitched squeal when turning the amp on. It goes away sometimes by turning the strength pot on the tremolo. It seems to be related to the tremolo because of that and when you turn the strength knob the squeal turns into a chirp that follows the tremolo.

I have changed out all the tubes and it is still there.

Please help if you have experienced this or have any guesses to what might be the issue.

[booj]

Pardon the pun, but it "sounds" like one of your filter caps has failed. An amp that old would do well with a re-cap job.

[music*child]

Pardon the pun, but it "sounds" like one of your filter caps has failed. An amp that old would do well with a re-cap job.

The guy I bought it from said he had it recapped, but prob wouldn't hurt to do it myself.

[booj]

New caps fail too. Only thing I can think of is bridge each cap with a cap of similar value and voltage rating and see if the squeal stops.

[ThermionicScott]

A couple thoughts:

* Perhaps one or more of the caps in the tremolo circuit have gone leaky. Does the squeal still happen if you pull out the tremolo tube (V6)?

* Doesn't look like the 6L6's have grid-stoppers on them -- adding some small ones may be a good idea.

- Scott

[TerryP]

Oscillation of the tremelo neon

Hi, I am new to the forums and have recently purchased a silvertone 1484 twin twelve.

The problem is there is a high pitched squeal when turning the amp on. It goes away sometimes by turning the strength pot on the tremolo. It seems to be related to the tremolo because of that and when you turn the strength knob the squeal turns into a chirp that follows the tremolo.

I have changed out all the tubes and it is still there.

Please help if you have experienced this or have any guesses to what might be the issue.

A very late post, hopefully useful to others with this problem.
I had very similar issue, chirping & ticking affected by tremelo setting.

Fortunately I had a 'scope and high voltage probe, so could look to see what was happening.
There was parasitic oscillation on the tremelo neon, bursts or continuous depending on tremelo setting. Frequency on mine was around 20kHz, but any extra capacitance (such as meter probe) on the node would give an audible squeak/squeg. My theory is that the neon was forming a relaxation oscillator with the capacitance of the connecting wire and circuitry. I isolated this capacitance with a 220k resistor in series with the neon's leg, wired between the leg and adjacent tagboard. All traces of the oscillation disappeared, along with all the audible side-effects.