Loud Plopping Noise when switching off Dual Rec

BesaMoogie

BesaMoogie

Well-known member
Hi all,
maybe someone here can help me with my problem.

I have a Mesa Boogie Dual Rectifer Rev G from 96 which is making a loud plopping noise when the power-switch is switched off. The plopp is followed by a quiet fading crackling. The longer I wait between switching off the standby-switch and the power-switch, the less pronounced the plopp will get.
I switched all the preamp tubes as well as the poweramp tubes, but the plopping noise stayed. I did not switch the rectifier tubes but the amp has the problem in the SolidState mode as well.

Does anyone have a guess what could cause this plopp??? I have another 2 channel DR which is dead quiet when switching off the power-switch and I never experienced this problem with DRs I owned in the past.

My first guess was that the amp is at an age of maybe needing a recap but that`s only a guess. If anyone can steer me in a direction it would be nice. I do have basic knowledge in electronics, can solder on PCBs, know how to drain caps and can bias powertubes etc.

Thanks!
 
A smarter person than I may 'pop' in here and help further but this is a fairly well known issue. Both when powering off and/or switching channels. I have a Rectoverb and it does the same thing. There are some tricks to minimize it but I doubt it is anything you can really fix, without sending it out to possibly be modded - and even then.

Basically (in a lot of cases) - it is just static electricity. Good luck,

https://forum.grailtone.com/viewtopic.php?t=36953
https://gearspace.com/board/geekzone/994062-mesa-boogie-tube-amp-crackle-when-power-off.html
 
311splawndude said:
A smarter person than I may 'pop' in here and help further but this is a fairly well known issue. Both when powering off and/or switching channels. I have a Rectoverb and it does the same thing. There are some tricks to minimize it but I doubt it is anything you can really fix, without sending it out to possibly be modded - and even then.

Basically (in a lot of cases) - it is just static electricity. Good luck,

https://forum.grailtone.com/viewtopic.php?t=36953
https://gearspace.com/board/geekzone/994062-mesa-boogie-tube-amp-crackle-when-power-off.html
Click to expand...

I can't say that I've ever noticed the pop on power up/down, but the pop when you're switching channels is a real thing. Every Boogie I've ever had did this the first time you switch channels on it after power up. So, it just became a ritual for me to "do the dance" and run the foot pedal through every channel after power up to discharge whatever was stored up. After that initial discharge, switched like normal and never heard it again.... until the next time it was shut down and powere back up.

That being said, all three of my Splawns "sqeak" when they power down. LOL
 
I`m totally aware of the pop when switching channels the first time. It is a well known thing with the old 3 channel DRs documented many times. What bugs me is that I have two other 2 channel DRs at the moment (yes, I`m a Recto-Nerd) that both don`t have the above mentioned problem. So I guess this is not general design fault like the channel switching thing.

@Dino 939 I tried different Power tubes but did not change the rectifier tubes yet. I will check this tomorrow.
 
Ok, I was able to solve the Problem.
Although the FX-loop was jumped and not active, the additional master which is only engaged, when the loop is active, was set wide open. Turning it down to normal levels made the pop disappear.
Now I`m a happy DR user again ;)
Thanks for your help anyway!
 
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