Tonepad TS9 Tone Control Issue--common problem?

[jacobyjd]

Ok, so I just finished a TS9 build for Tonepad, and it works just great except for one problem--the tone control (swapped a 25k lin. for the 20k W) seems to be malfunctioning.

At full counter clockwise, it sounds as expected, kinda muffled. As I turn the tone knob toward the right, the tone doesn't get any less bassy and I hear a very noticeable volume drop (90% below unity at full clockwise).

given the functionality of the rest of the effect, I can only assume that the issue is isolated to a tone cap somewhere, but I can't seem to locate the issue.

Any suggestions?

[jacobyjd]

bump---I'll be taking a look at my soldering for the tone stack tonight and see if there are any other issues that might come into play here. Still though, any suggestions from someone who knows TS clones would be great 

Thanks!

[petemoore]

  Could be the treble rolling off is enough of the overall signal to be termed 'volume drop.
  Although it sounds like it could be a mis-valued component [such as a larger than usual treble rolloff cap] that's just one thing to maybe look for.
  I used various non-TS-tone pots, mostly 25k or 50k trimmed to a lesser value, and wrong taper, and realized the taper does matter in this case, but volume dropping and no treble 'rising doesn't ring, I'd guess the control'd be bunched up at one end more than the overall range being moved down in frequency or reduced.

[jacobyjd]

yeah, that's exactly what's happening--the treble just disappears...I'll check the component values as well just in case.

Do you know which cap actually does the treble roll-off? i'm guessing it's  the .22uF one connected to the tone pot.