Help with my Mesa MarkIIB

[Marcus]

I just picked up my second Mesa MarkIIB head. I regretted getting rid of my first one. These amps can do anything from shimmering clean to metal. This one I just got has some issues. First off; when I'm on the lead channel the treble doesn't seem to do anything including the push/pull. It works on the clean channel(both functions). This one also has muddy bass and seems a little thin on the bass side. I used to keep the bass on 1 on my old one and I like a lot of bass. My current one doesn't seem to have as much gain as my old one. The tubes are good and I cleaned the pots, switches and jacks. There is no obvious damage inside the amp. It's actually really clean. I checked the schem. and its bone stock. Please help a brutha out!!!!

[rzenc]

its bone stock.

How old is it?

muddy bass and seems a little thin on the bass side. I used to keep the bass on 1 on my old one and I like a lot of bass. My current one doesn't seem to have as much gain as my old one. The tubes are good and I cleaned the pots, switches and jacks. There is no obvious damage inside the amp. It's actually really clean. I checked the schem. and its bone stock. Please help a brutha out!!!!

Check power supply e-caps. They dry with age and symptons like you are describing are some of the issues that comes with it.


Best Regards

R.

[stratele52]

How did you check tube , by replacement or tube tester ?

Check power supply voltages

Schematic here ;

http://schems.com/manu/mesaboogie/boogie_mkiib.pdf