Drive control issue

[Electron Tornado]

Starting with the Buzz Box from runoffgroove, I made some changes and came up with the circuit here. It's a nice, fuzzy distortion. However, the 100k pot on the front I have as a "drive" control doesn't seem to have that much control. The volume knob on the guitar does a better job of cleaning up the tone. I've tried a few different things with the drive pot, but nothing works as well as the guitar itself.

I know, I could eliminate that pot and just use the guitar to clean up the tone, but I'm trying to understand why one control works better than the other, and how to get the desired effect from a control pot in the circuit.

Thanks for any help.

[Madkatb]

I think the other lug  needs to be grounded.

[Electron Tornado]

I think the other lug  needs to be grounded.

I tried that. I set it up like the sustain control on the Big Muff. Here's the schematic: http://www.diystompboxes.com/smfforum/index.php?topic=98761.msg864262;topicseen#msg864262

[Bill Mountain]

The pot as it is, is not doing much.  It's just changing the series resistance (10k to 110k) at the front of the circut.  If you ground the bottom leg it'll function like your guitar volume control.

[Kesh]

ground it and maybe change to a log taper

[Electron Tornado]

ground it and maybe change to a log taper

I tried that. It performs about the same. Sooo, with the circuit's similarities to the Big Muff, I decided to see how the same control performed on the Big Muff. I got out my trusty Big Muff I built from a General Guitar Gadgets kit, and .... the sustain control on it cleans up the signal about the same as what I've got going on in my schematic.

The best way I could describe the tone of the circuit is like a trashy Big Muff.