strange sound coming from cab or amp

[thekorean]

I hear this cracking/static sound. What is strange is that if I isolate the static (don't know how just pretend its not there) it sounds fine but sometimes I can't even hear my playing because it just statics up and is unplayable until I twist a few knobs. The static isn't necessarily loud but the notes just don't get through. The clip light does not come on when it occurs.

I've tried flicking/hitting (not too hard) the top of the head and it clears right up usually to come back in around 5-10 minutes and sometimes it goes away. Other times I nudge the cab around and it goes away and it is around the same time period.

I am prepared to take it to a tech but am not sure what to bring as the cab is 100+ pounds and not a real treat to lug out.

Mainly I want to know the possible problems as I have a gig coming up soon where I want to use my rig and not a DI.

Rig:
Ampeg 3-pro (older)
Peavey TVX 410

Thanks for the help in advance and I'm sorry if this has been covered already. If I didn't describe this clearly enough as I'm a bit confused please ask and I'll try to answer to the best of my ability.

[billfitzmaurice]

I'd start by cleaning all the potentiometers and jacks; there are products made for that available from Parts Express, amongst others.

[thekorean]

what would be used exactly?

[thekorean]

any fresh ideas

[Dan Knowlton]

Nope, no real ideas. I get really strange sounds coming from my amp/cab...but that is just my playing!

All kidding aside - did you use a circuit tester on the wall socket?

Dan K.

[thekorean]

alright i'll try that

[BassmanPaul]

Have you tried using a different cabinet? You need to isolate which piece of equipment is causing the problem. If the amp has an effects loop try jumpering the send and return with a signal cable, sometimes dirty contacts can cause what you discribe.

If it is the amp take it to e tech to be checked out.

Paul

[thekorean]

I don't have another cabinet but I plan to maybe get one tomorrow. So instead of plugging the cab into the standard 1/4 jack, I would put it into the send/return using a signal cable correct? What is this signal cable you speak of anyway?

[johnk_10]

to test the send/receive jacks, plug your bass into the front of the amp as usual, but also plug a short guitar cable from the send to the return jacks on the back. this bypasses the switches in the jacks that normally complete the circuit from the preamp to the power amp. you still must use the speaker output jack to go to the cab.

[thekorean]

okay I got a tiny bit of distortion but nothing too big. Would that be a problem?

[johnk_10]

probably not.

[thekorean]

what does that mean?

[thekorean]

Could the preamp possibly be the problem because I am assuming the tubes may be old. Also what did testing the send/receive jacks mean?

[lbwdog]