Ampeg svt 4 cutting out

[drewbiewan]

just bought an ampeg svt 4 and the guy i bought it off of said everything was fine and he just had all the soldering joints resoldered. the problem is when i play the sound keeps cutting out. ive tried both poweramp outputs to make sure it wasnt the connection to the cab. im thinking its something with the input maybe??? any ideas would be great. thanks.

[Mark Black]

Hi -

I'm kind of wondering just what "he just had all the soldering joints resoldered" really means in this particular case. Reason being - these amps (and all other modern ones from Ampeg in my experience) have a LOT of places where solders go bad. One often-overlooked spot is the ribbon-cable multipin connector pins joining the front panel PCB to the main PCB.

In my opinion properly retouching ALL the controls, jacks, switches, multipins, LED's, QD connector tabs, bridge rectifier, fuseholder, AC inlet, and all large or heat-producing components in addition to any other suspicious-looking joints is pretty much mandatory on these (and so many others these days) in order to get things right and prevent future problems.

Depending on your level of electronic expertise there are a few troubleshooting methods you can try. One basic thing (mentioned in this forum many times) is to plug a cord from the effects out jack right back in to the effects in jack to eliminate (or illuminate) dirty normalling contacts in the jacks. Same goes for preamp-out to poweramp-in.

If you are comfortable getting a little farther "under the hood" you could take off the top cover and using a NON-CONDUCTIVE implement like a chopstick or wooden dowel tap on the PC board to see if you hear noise from a problem connection or cracked solder.

Keep all current & past advice on this forum (and many others) in mind when doing testing with the cover off and power applied. If you are at all unsure or uncomfortable, or lack knowledge of basic electronics safety, by all means bring the amp to a pro!

Good luck!

[Enzo]

ANd let us think for a moment. If the amp was working so well, WHY would he have had all the joints resoldered? SOunds like he was having the same issues to me.

Makes me think of a scene from home:

"Hi Mom, I'm home from school, and nobody sent me to the principal's office."
That would me me suspicious I tell you.

"My amps is fine, and I just had someone take it apart and resolder everything."