Question about the Peppermill (modification similar to the Keeley Katana?)

[comfortably_numb]

So I played a Keeley Katana a while back and really dug the sound.  It's basically a super clean boost with a push/pull knob to add just a slight amount of grit.  The only way I can think to do this is to add a unity gain transistor stage after the intial booster which would then be overdriven.  This way, there's no volume drop, as with diodes.

So, my question is - can I switch the second gain stage (after the gain pot, before the .047uF cap) in and out to achieve this? 

Also, I imagine that this stage isn't at unity gain, so what would need to be done to accomplish this? 

Could something similar be done by placing a unity gain FET buffer after a Mosfet boost?  Also, I'm very interested in Joe Davisson's Vulcan idea, where a diode is placed before the fet stage to keep it from being hard saturated.  Could this be utilized here in a unity gain configuration?

Lots of questions I know.  Any insight is appreciated.  Thanks.

http://www.runoffgroove.com/peppermill.png

[comfortably_numb]

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[Ben N]

Late as usual. 
I once askd about this, and I think Mark Hammer told me the simplest way to do this, assuming you have enough gain to spare, is to switch betwen your clippers and a resistor about equivalent to the diodes' drop.
Instead of raising the bridge, lower the river.
Ben