Mark IV problem, all channels quiet/thin

[fatbagg]

Just moved and got my amp delivered (finally), but there are problems... The ch.1 treble pot is broken, and the entire amp is wack. All channels are quiet and very thin, almost out of phase. I can turn ch 3 channel vol up to 5-7 and the master volume up to 5 and almostntalk over it, and it is very thin and very strange sounding. Very little drive on any channel. All tubes are glowing, tapping doesn’t indicate any issues. I will be changing them all out, but does this sound like anything in particular?

Back knob is on Ft Sw (with foot switch plugged in).

 

[jediguitarist]

Did you figure out the problem? Friend of mine has a similar issue with his IV. Started happening when the amp fell face forward while packing up from a gig. Can get volume but only if masters are past 5 and output is past 4-5. Everything sounds normal, but there seems to be so much play on the volume controls now.

 

[fatbagg]

Never got it fixed. I sent it out to an authorized repair guy, and while the volume issue is fixed, it sounds fizzy and unresponsive. I have replaced tubes, and it sounds like a pocket amp. I’ve already spent $200 on a repair and now It’s looking like I’ll have to start over and send it to Mesa.

 

[bgh]

You might want to give them a call first and ask them what they think.

I have had amp issues before, and when I called, they helped me figure out what it was. Once it was something I could fix on my own. Another time, I had to send it in. George (at Mesa) was excellent in how he fixed my amp and, w/o me having to ask, fixed a couple of other things - all on the same nickle.