Mark III black dot (raspy overdrive)

Just bought what appears to be a near-mint condition Mark III (black dot or stripe?). It’s loaded with an EVM12L, Simul-Class, and Reverb. Only seems to be missing an onboard EQ. I’ve owned a couple of Mark IIB’s, a couple of Mark I RI’s, and another Mark III about few years ago (blue stripe).

Anyway the overdrive on this amp sounds like gravel. Just raspy and like a bunch of bees . I’ve tried various settings without success. I don’t recall my previous Mark III’s overdrive sounding like this. The clean channel is okay but not very inspiring.

I guess I’ll take the amp to my tech after the holidays and have it checked out and also to covert the two outer EL34’s to 6L6’s.

Any recommended settings or anything else that I should check out on the amp to improve tone would be much appreciated.

Thanks,
Grid

Try some different preamp tubes in the first instance; although the amp may have other issues tube swapping is something you can do yourself. This thread has a little info:
https://forum.grailtone.com/viewtopic.php?t=67761

The manual also has a section on preamp tubes:
http://www.black-records.de/download/markIII.pdf

Thanks, I have a lot of extra pre amp tubes to try.

DC3 Gridlock said:

Thanks, I have a lot of extra pre amp tubes to try.

Click to expand...

Cool -- yeah worth a go.

wildschwein said:

DC3 Gridlock said:

Thanks, I have a lot of extra pre amp tubes to try.

Click to expand...

Cool -- yeah worth a go.

Click to expand...

I’ve played with the push-pull knobs (bass pull-shift and master1 pull-deep) using Volume 1 and got improved cleans.

I was also able to get the amp sounding good with my J-Rockett Dude OD pedal while using the Volume 1 channel.

Next, I’ll work with the Rhythm 2 channel and I may just give up on Lead 3 channel for now.