Ampeg SVT$PRO Problem...

[stevenkh]

We have a USA Made Ampeg SVT4PRO.

Everything performs great on the unit EXCEPT about two weeks ago the unit started "Muting" itself at will.

Example: Power unit up, plug in, push mute button out. The unit will pass sound through...then the red peak/mute light will come on for a second or two, no sound, then the light will go out and sound will resume. It will mute itself for a few seconds to minutes (the time varies each time). I have noticed that if you tap your hand on the top of the amp it usually un-mutes itself.

Also it does not matter what temp the amp is running at...it will do it 20 seconds after it is powered up or 20 min after and everywhere in between.

Any advice as to what the problem and fix might be???

Thanks

[dukeisdog]

Is the head on the cab? Maybe the cab vibrated a wire loose or something.

[JimmyM]

Dirty mute switch maybe? Corrosion in the effects loop jacks maybe? Fault in the protection circuit maybe? Sounds intermittent, so it's probably dirty contacts or a loose wire. Try spraying some Deoxit on the mute switch and effects loop jacks before you do anything else.

[GBBSbassist]

I had the same problem with that amp as well.

Make sure that if you're using an active bass, you flip the -db button. That seemed to fix it for me.