Amp Power Switch pops ?

[crawler486]

Hi guys!

I got a Fender Princeton 112 Amp.
It has this very big Pop when I turn the amp's power switch.
It also pops when I turn on/off the lights or switch on/off any electrical device.

the over the top POPPING occurs when I switch off the amp after an extended period of use.

I once read about putting a pulldown capacitor but can someone
teach me the procedure in detail? I don't want to risk frying
my amp.

Thanks.

[R.G.]

The pulldown resistor trick is highly specific to effects circuits. It would be unlikely that it would help with a whole amp. The problem with the amp lies in the amp's internal design, not on a simple lack of a pulldown resistor.

[Aharon]

Of alll the amps I'have built only one pops when I turn it off,my Trainwreck "clown" (er....sorry.clone).After pondering for a while why I came to the conclusion that it is because I put the HV switch before the rectifier and not after,something I have to change when I get the urge to do some surgery on an otherwise perfectly working amp.

I'm not saying this is the case on yours I just thought I would tell the story.  :wink:

One thing that can aliviate the pop is a 1KV 0.01 cap across the sw poles.
Don't do this yet,wait for RG to confirm and explain better,please. :idea:  :?:
Aharon

[petemoore]

yupp they do that.
 sounds like yours does it loud.
 seems there might be a way to soften the power on/off without a variac?
 just suggestive rambling, with no background
 'fake' stanby switch for output to go to dummy load? again .. no background...and added risk of output problem.

[crawler486]

hmmmn...so the problem might be harder to fix than I thought so.

Any other ideas would be greatly appreciated.

If only I could find that specific thread that that has this
exact problem. got to dig deeper...

Regards