Ampeg combo 'pops' when turning off

[LITTLEWING]

I've just acquired an Ampeg BA115 combo and when turning it off (both volumes down) it pops through the speaker a second after switching off. I used one a while back in a local studio and it did the same which I assumed was something that needed attention after time with all the different player's usage. This one does exactly the same and I wondered if it's anything to worry about or is there a mod that an amp tech could or should do? I assume it's not ruining the speaker in any way?

[CamdenRob]

Other more knowledgeable folks to follow but my Glocknklang did this and i think it was just a capacitor discharging or something... made a god awful noise if you turned the amp back on again before the pop had occurred...

[MoonBassAlpha]

Nothing to worry about. Loads of older design amps do this. I think it's just the power supply capacitors discharging a bit asymmetrically. Many modern designs have a relay that disconnects the speaker before the power supply is removed, hence no thump.

[Number6]

Capacitor discharging i believe.....i had a very old Carlsbro that used to do this up to about 5 mins after i switched it off.

[James Nada]

My very first combo did this.
It still does it 26 years later but otherwise works just fine.

[rmorris]

[quote name='MoonBassAlpha' timestamp='1468675315' post='3092569']
Nothing to worry about. Loads of older design amps do this. I think it's just the power supply capacitors discharging a bit asymmetrically. Many modern designs have a relay that disconnects the speaker before the power supply is removed, hence no thump.
[/quote]
+1 yep - cap discharge thing. Can be a bit disconcerting if it gets to FOH 😣
If an issue new and poss tighter tolerance PSU caps may help to some degree. As stated many designs avoid it by anti thump circuits at turn on and turn off.