Carvin MTS 3000 head Making a crap load of noises

[Aden]

I've got a used Carvin MTS 3000 head, one of the 50th annaversary dealies. Has newish tubes in it, probably with less than 20 hours of use and it sounds great, but the thing acts possesed sometimes.
I often get a slight if not big squeel when using anything in the effects loop, and the effects loop is alwayse noisy, and sometimes the whole thing will let out a non stop whine or squeel even with guitar volume at zero or unplugged. But the thing is it's not spacific to a channel. It does it on both channels some of the time, and sometimes it works just fine. I've tried the slap test when it's working properly, (turning it on and playing a bit then giving a firm but not hard slap on the top of the head) and it will start maknig noise again. To fix it I either have to switch channels and unplugg everything in the effects loop or turn off the head and let it cool down.
I'm guessing something is wrong with the effects loop and may be a few the tubes are loose or something but I really know less than zero about fixing amps.

Anyone have a clue what is going on or did I just buy a crappy amp?

 

[DankStar]

Re: Carvin MTS 3000 head Making a crap load of noises

I used to have some Marshalls that got all weird with the effects loop. I also messed with the loop once with my Carvin X100B and I swear it was acting weird too.

 

[JLagoon]

Re: Carvin MTS 3000 head Making a crap load of noises

My TriAxis was like that last night! I mean, it worked fine before, but it made fluctuating loud noise when it's idle, especially the lead channels. My clean channels were also noisier. ????????

 

[saladin]

Re: Carvin MTS 3000 head Making a crap load of noises

Sounds like a tube problem, even though a tube is new they don't always come that way from the factory (like everything else). I would try pulling the preamp tubes out (one at a time) and making sure they get plugged back in tightly. It could be the V4 tube is microphonic. It controls the loop, it is marked as to which tube it is on the amp chassis. That is most likely your problem. You could try changing that tube to another position and testing the amp.

 

[Gearjoneser]

Re: Carvin MTS 3000 head Making a crap load of noises

Sounds like a tube problem, even though a tube is new they don't always come that way from the factory (like everything else). I would try pulling the preamp tubes out (one at a time) and making sure they get plugged back in tightly. It could be the V4 tube is microphonic. It controls the loop, it is marked as to which tube it is on the amp chassis. That is most likely your problem. You could try changing that tube to another position and testing the amp.

+1. Find out from Carvin which preamp tube controls the FX loop, if any.
Amp companies typically use the cheapest tubes they can get away with.

If it's not tube related, it's almost always jack related. When a cable gets yanked, it often breaks the solder connection. That means that an FX loop jack could have little cracks on it's solder connection. That's why the problem is intermittent, and can be effected by smacking the side of the amp, or flexing a cable. If wiggling the cables makes the problem act up, unplug the amp, open it up, and examine the areas where all the female jacks are soldered to a PC board. Use a soldering iron to reset them all.