Ampeg SVT-3pro random drops in volume

[1987]

Hi all,

So I was playing a gig the another night and it seemed that my SVT-3pro head was experiencing random drops in volume. There's no crackling noise suggesting a blown tube. Does anyone have any ideas at what could be causing this? Any advice is greatly appreciated.

Cheers.

[Foz]

clean the send/return jacks [shoot a squirt of Caig Deoxit in the holes and onto a 1/4" plug - run the plug in out 20 times on each jack - swipe with a q-tip and repeat]

[Jim C]

My 3-pro had problems with bad solder traces (on 2 separate occasions) which may be your problem
Cleaning the send return jacks is a good place to start as well as just using a guitar jack from send to return to bypass these jacks
Still could be a tube IMO

[prd004]

The SVT-III PRO has power amp in and preamp out jacks on the rear, you can use these to determine which section the problem lies, it will eliminate a lot of guesswork. So send the preamp out to a mixer, PA or, external power amp/speaker. If you still heave the same problem the trouble is in your preamp section. You can also run a line level to your power amp in. THis will give you a lot less to look at in order to find the problem.