# Loud pop on power off



## sctrotts (Oct 8, 2015)

Might be a silly question to a common occurrence but.. my Peavey Classic 30 makes a loud pop sound when I switch it off. I have always turned my volume knobs to zero before doing so, yet this happens. Amp is a recent kijiji buy so.. Maybe I need it svcd?


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## Destropiate (Jan 17, 2007)

Most amps I've had have made some sort of noise ranging from a pop to a squeal or both when powered down. I find leaving the amp on standby for a minute or so before hitting the power switch can either stop that or make it less audible. If it's not really loud I wouldn't worry so much.


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## sctrotts (Oct 8, 2015)

No standby switch on this rig.. guess I'll wince and plug my ears from here out til she blows.


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## Destropiate (Jan 17, 2007)

If it's loud enough to make you wince it might be good idea to get it looked at. I have zero experience with tube amps with no standby switch but someone who does should chime in here eventually


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## diyfabtone (Mar 9, 2016)

Not abnormal, but it could indicate a power supply problem - best to have it checked by a tech.


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## greco (Jul 15, 2007)

For how long has this been happening? (i.e.,since you first got it or it just started somewhat recently)
Has the "popping" been getting louder since it first started?
Did you buy it new? 
Has it been popping since you first got it?


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## Paul Running (Apr 12, 2020)

sctrotts said:


> I have always turned my volume knobs to zero before doing so, yet this happens.


That would indicate the issue is after the pre-amp. I notice on the schematic that this model has the diode-protection (CR4 and CR6) for the primary of the output transformer. Those diodes are fast-recovery types that clamp overshoot from the primary winding. You may wish to check those diodes....overshoot can produce a pop on hard power-downs.


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## BlueRocker (Jan 5, 2020)

Paul Running said:


> That would indicate the issue is after the pre-amp. I notice on the schematic that this model has the diode-protection (CR4 and CR6) for the primary of the output transformer. Those diodes are fast-recovery types that clamp overshoot from the primary winding. You may wish to check those diodes....overshoot can produce a pop on hard power-downs.


Although this is not my issue, I'd like to thank @Paul Running (and others) for being so quick to provide technical advice to those of us without the knowledge and skills. I enjoy reading these posts, thinking it will somehow make me smarter.


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## GuitarTalk (Dec 25, 2018)

sctrotts said:


> Might be a silly question to a common occurrence but.. my Peavey Classic 30 makes a loud pop sound when I switch it off. I have always turned my volume knobs to zero before doing so, yet this happens. Amp is a recent kijiji buy so.. Maybe I need it svcd?


Had the same issue on my 57’ tweed pro and later on my 60’ bandmaster happened when one of the filter caps started to go (luckily in both cases, the issue had nothing to do with the transformers). U can also tell it’s a cap if the amp gets louder/quieter randomly when powered on. Definitely get it checked out as you can ruin your amp if the cap goes out “in style”.


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## Todd MacCulloch (Mar 8, 2018)

does the same popping occur when you unplug from the wall?
if not, it maybe related to the switch.


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