Mad Bean's Dig Dug Tone Sucking Problem

[KazooMan]

Pictures below, text first!

I just built a version of Mad Bean's "Dig Dug" pedal (based on the zVex Ooh Wah and usually discussed on another forum).  The schematic is reproduced below (hope this is OK with you Bean).  Details are available at Mad Bean's site.

The original layout for the pots board would not allow me to use the 1/2" knobs I wanted so I redid it in Photoshop.  I, like others as I learned later, installed the leds on the pot board backwards (following the layout) but that was not a big deal.  I also found that the pots on the board were only effective in the last few degrees of their rotation so I experimented with smaller value pots and the resistors in series and finally settled on a set that gave a larger range.  I should note that the problems that I am having now were there with the original values for the pots and the series resistors.  

So, I have the original schematic, with an enlarged board for the pots (this required a few changes to get the "2/4/8" selector switch connected) and I changed the value of the eight pots from 100K to 10K (maybe should have gone to 25K).  

The pedal works fine, except for the "filter pot".  There is NO effect with this pot turned all the way clockwise.  The effect only comes in for the last few degrees counterclockwise for this pot and what happens is as the pot is turned counterclockwise there is a huge roll off of the tone to the bass end.  With the pot all the way left this pedal is really fun, but it is all bass.  I tried just bridging the pot and caps out of the circuit, to no avail.

Is there any way to recover the treble end for this pedal?

PS:  Yes, I used an old, recovered DPDT switch (yuck) and I did chip the finish during all of my attempts to get things in order.

Pots Board:



Guts:



Pedal:



Schematic:

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