Terrible squealing on Dual Rec. Please Help!

[beavis1957]

Ok....I bought a Dual Rec used about a year ago. It seemed to be well kept. I had no idea how long the tubes had been in it. It's been wonderful for the past year.

I went ahead and preemptively bought some JJ 6L6's and preamp tubes just in case.

Well, last weekend, I noticed that there was quite a bit more hum coming from the amp than what's normal, so I decided to go ahead and retube since I have a gig coming up in a couple of weeks.

Everything seemed fine when I fired her up, but when I get the master above a certain level I get this awful screeching feedback sound coming out of the amp. It seems like it does it on almost all of the tube settings....just some take a little more master volume to produce the sound.

I changed the tubes back to the old setup and it still does this.

Any ideas? I've never had this kind of noise/feedback before.

 

[Russ]

It may be a microphonic preamp tube. Have you tried swapping out the 12ax7's yet?

 

[Platypus]

It may be a microphonic preamp tube. Have you tried swapping out the 12ax7's yet?

+1

First place I'd look.

 

[beavis1957]

It may be a microphonic preamp tube. Have you tried swapping out the 12ax7's yet?

Yes, I did. I swapped them all out, and that's when it started. I then swapped back to the old ones and it's still there. Very frustrating.

Thanks for the suggestion though.

 

[Humbility]

Maybe one of your new power tubes is buggered. Arcum's Razor: When faced with a problem, the simplest answer is most likely the correct one. All you've done is change tubes. Follow the manual and do the tube test. Then if all else fails, call Mesa directly, explain, and ask for advice. They made it, they might know.

Hum

 

[ibanez4life SZ!]

In my experiences, JJs are fairly noisy tubes...could be a bad one.

 

[beavis1957]

Ok, I kind of feel like a moron.

The squealing was a bad guitar cable!

I've never had a cable go bad in that manner. They normally just crackle a little or just go out. This thing made the amp squeal like a banshee.

It still is much more noisy than it used to be.....don't exactly know why. At least it's playable now.


Thanks for the suggestions anyway guys.....and don't be too hard on me for being an idiot.

 

[Russ]

That kind of thing happens with cables. You often take for granted that they work. One day they do something stupid. That is why I like the lifetime guarantee cables. This way you can just take them back and exchange them. Just be sure to use a major brand. I got burnt a couple times with SpectraFlex type cables because the companies disappeared.