Less gain for R2 mkiii green stripe????

[Direwolf]

Hi all. I have a mkiii green stripe I bought a few months ago on eBay. I've been tweaking and what not since I got it. After righting all the past wrongs with it I have finally started hearing the potential this amp has. I had to replace a few resistors and all the coupling caps was replaced with some orange drop polyester. I know it's not the stock caps but I really love the mid range these caps produce. I don't use this amp for metal. I'm more of a fusion, blues, and some improve jam kind of player. Anyway, the best set up I found to my taste is R2 as clean and lead with analogman ts9's and a cusack screamer. My problem is there is too much gain in r2 to get a good loud clean. I've swapped v1 for a 12au7 and some 'funken <> 12ax7s in v2&3. This cleans up r2 but I really have to crank the tone controls. Also the low end seems to be lacking also. My question is this, is there a way to reduce gain in r2 with a resistor swap or any other method other than a lower gain pre amp tube. I've searched the site over and all I can come up with is how to get more gain. I really appreciate any help that is offered. Thanks again!!!

 

[Boogiebabies]

For the R2 Mesa used a 3.3M resistor with the 180pf cap in parallel to the clean/lead channels 3.3M - 20pf circuit.
When R2 is engaged the resistance is 0 Ohm and 160pf to the V2B's 10K input grid resistor. A 6.3M resistor here will keep the gain
the same as the clean channel, so trying 5M or 4M may get you in the ballpark.

The second side of the relay switches the grids ground reference from 6.8K to 330K bypassed by a 47pf cap to prevent any oscillation. The
reduction in ground reference of the 330K increases gain, so lowering it will reduce gain. Where you like it will be up to
your ears.

 

[Direwolf]

Thanks for the reply. :mrgreen: I hate to respond with another question but...... Does changing any of those values affect the lead channel? I use the footswitch to channel change with the R2 knob pulled. This cascades R2 into the lead channel from what I understand. (?). Sorry if this is a dumb question and again thanks for the info!

 

[Boogiebabies]

No effect on R1 or lead. These resistors are inly used for R2 and activated by the relay,

 

[Direwolf]

Thanks for your time boogiebabies!!!! You rock!!!!!!