Mark IV white noise!! Help!

[MusicManJP6]

At practice today the Mark IV started out sounding fine but as practice went on i started hearing white noise, and after about a total of an hour and a half, the noise was loud enough to be alarming and make me not want to play anymore for fear of hurting the amp. The amp still sounded OK, although it sounded like it was missing some tone maybe. Any ideas as to what it could be? Thanks guys.

Adam

 

[Boogiebabies]

A bad preamp tube. Usually the V1, 3 or 4. It gets even worse with the lead bright pulled.

 

[MusicManJP6]

I will try swapping some preamp tubes out this week and see if it goes away. The tubes are pretty new, but that doesn't mean they can't go bad...

Anyone else have any suggestions for things to look for to fix the problem?

EDIT: A tech friend of mine seems to think it is tubes as well. I'll be making a visit to the music store this week and doing a preamp tube replacement. Any recommendations?

 

[Shep]

I will try swapping some preamp tubes out this week and see if it goes away. The tubes are pretty new, but that doesn't mean they can't go bad...

Anyone else have any suggestions for things to look for to fix the problem?

EDIT: A tech friend of mine seems to think it is tubes as well. I'll be making a visit to the music store this week and doing a preamp tube replacement. Any recommendations?

boogie's don't suddenly just do that.. it's always a tube or a lead or pedal..

 

[MusicManJP6]

Thanks! Still new to the boogie amps. I'll update the situation once I find the culprit...

 

[MusicManJP6]

Turns out I neglected to change the 12AT7 reverb tube in V4 when doing the tube replacement a while ago. My Peavey XXX has 4 preamp tubes and the Mark IV has the additional tube for reverb, so I missed it when swapping the tubes out. The old tube I took out rattled when I shook it, like a blown lightbulb. Anyway, all is well in the land of the Mesa!

Thanks guys...

 

[Platypus]

sweet