DUAL REC PROBLEM: LOUD HUMMING

[tempest1226]

no matter what i do, whenever i turn the amp up, there is an obnoxious loud hum. Its really bad. It was never there. There was always little hum/hiss when turned up, but this is like yelling loud. any suggestions/ideas of what this is would really help. thanks everyone

 

[mikey383]

Check your preamp tubes and your cables. Most likely, either one of your cables has gone bad, or a preamp tube has gone bad.

Or, you could have a grounding issue - either in the amp, or in your electrical wiring.

I'd eliminate everything else first...the guitar, the cables, any pedals or effects, then go for the tubes. Try swapping V1 with V4 or something like that and see if that helps.

 

[tempest1226]

i think it was when i accidently turned on the amp without the cabinet plugged in. How can i check to see if it was power tubes and ive also heard that if you do this, you could possibly damage the trannie. IF that would be the case. Is that covered under the 5 year warranty?

 

[mikey383]

So it started right after you turned it on without a cabinet plugged in? Mesas can withstand a brief moment without a cabinet, but if you played your guitar through it for any amount of time, you either fried the output tranny, or killed some power tubes.

The best thing to do would be to replace the power tubes, and see if that helps. If it doesn't, then take it to a tech in your area that is Mesa approved and let them know what it is doing.

It probably won't be covered under warranty, but you might be able to squeeze by if you play dumb and act like you don't have a clue what happened to it.