Pop noise when turning on or off stanby

[Briman24]

I have two jcm2000 dsl's and one of them sometimes makes a popping noise when turning on or off standby. It does it often but not all the time.
The other dsl never does it. My old 2203 never does it either.

The amp works fine otherwise and sounds awesome but was wondering if anyone knows what causes this exactly? Would love to remedy it if possible as it is annoying sometimes.

 

[311splawndude]

That is just the speakers reacting to the power coming on and off (actually the resistance load to the cone of the speaker). It is pretty normal. If it is really bad or only bad on one amp, like you indicated, it could be an indication of a bad ground. That is kind of a can of worms so it depends on how bad you want to fix - but ultimately may be something you have to live with. If that is the case, just turn the volume down before turning on an off.

FWIW - both of my amps popped pretty good when I had my ground loop issues but now they are pretty quite going on an off.

 

[Briman24]

Thanks Splawndude. Weird how one of them does it and the other doesn't as they are both plugged into same power bar and have same pedalboard hooked up. I can live with it but was wondering what the hell it was that causes only one of them to do that.

 

[Briman24]

My little practice amp does same thing but it is solid state marshall mg15 and has no standby. When you turn off or on ....there is a pop sound.

 

[311splawndude]

Thanks Splawndude. Weird how one of them does it and the other doesn't as they are both plugged into same power bar and have same pedalboard hooked up. I can live with it but was wondering what the hell it was that causes only one of them to do that.

I think some of that may have to do with capacitors and how they hold power and the possibility that one of your DSLs has a weak ground somewhere (which would involve sending it somewhere to trace that out). And yes, this can happen with ss amps too.

Maybe someone else smarter than I will chime in on this.

 

[glpg80]

Could be a failing standby switch that’s arcing.

 

[Briman24]

Could be a failing standby switch that’s arcing.

Thanks. I will look into buying a switch and install it if they are not too expensive.

 

[SpiderWars]

When turning OFF, just flip the Power OFF instead of Standby. Then Standby after. That often helps.

 

[Briman24]

When turning OFF, just flip the Power OFF instead of Standby. Then Standby after. That often helps.

Yeah but i don't want to power down the amp. For example, the wife will call me for dinner so will be back in 10 mins to play again and turning it off and back on wears tubes faster so i've been told.

 

[SpiderWars]

Yeah but i don't want to power down the amp. For example, the wife will call me for dinner so will be back in 10 mins to play again and turning it off and back on wears tubes faster so i've been told.

For 10 minutes I'd probably just leave it on but I do see your point.

And just to comment on it, I'm not so sure turning the amp to Standby for 10 minutes and then turning it back on is less wear on the tubes than just leaving it on. If I had to guess...if anything it's more wear on the tubes but it's probably so negligible that it doesn't matter. And if the amp is popping every time you do...again I'd argue that it's better to just leave it on. Tubes just idling are not wearing out very much.

EDIT: I can't tell you how many times I've left my Rocket clone (4x EL84 with a HOT cathode bias) ON over night. It's still rocking the same Russian tubes and they still sound great.

 

[Briman24]

For 10 minutes I'd probably just leave it on but I do see your point.

And just to comment on it, I'm not so sure turning the amp to Standby for 10 minutes and then turning it back on is less wear on the tubes than just leaving it on. If I had to guess...if anything it's more wear on the tubes but it's probably so negligible that it doesn't matter. And if the amp is popping every time you do...again I'd argue that it's better to just leave it on. Tubes just idling are not wearing out very much.

Yeah that's a good point. Probably less wear not loading the the tubes off and on again at all!

 

[GerryJ]

Does the amp pop if it's plugged into a separate outlet & used by itself, no 2nd amp, no pedalboard? If not, then as mentioned above it could be a ground loop issue.

 

[Briman24]

Yes it still does it when plugged in separately.

 

[vertigo]

I put a 630V 0.047uf cap across the terminals of the standby switch on the amps I built. Suppresses the pops

 

[Ernstudet22]

A new switch along with a cap as vertigo suggests is a good place to start. Make sure your tube sockets are clean and tight while you're in there.

 

[glpg80]

I put a 630V 0.047uf cap across the terminals of the standby switch on the amps I built. Suppresses the pops

I’ve done the same trick to my 5150 II.

Technically not having the standby switch in the discharge path of the caps eliminates the issue without the cap, but that’s not always easy to mod to do.

It should be noted to the OP that the value is actually not important, just don’t go too big otherwise the discharge time can take forever. And definitely make sure you use a high voltage rated cap at least twice the B+.