Serendipity Question - Expanding Range

[frankie5fingers]

Can't say enough about the pedal.  It's almost impossible to find a sound I don't like, no matter what the setting.  The only mods are input cap and C3 are 220n, everything else at spec.  I have no problem per se', but I usually wind up with the drive knob at around 8-9:00.  Sounds great, but I still have 3/4 of the rotation that I don't use.  It's the same (though opposite) for the Voice knob.  I usually wind up with it at 3-5:00, again leaving 3/4 of it's rotation unused.  using 500kB drive, 10kB voice pots. I'm just wondering how I might open up the range a bit.  Thanks

[mgwhit]

You could try an A500K (audio taper) or a B250K on the Drive pot.  A500K would preserve the maximum drive, but give you more play in the low-gain regions.  B250K would lower the maximum drive.

I'm having trouble visualizing how an audio or reverse log taper would change the Drive pot functionality.  If you don't mind losing some of the range, you could replace R3 with a 5K6 or 6K2 and then use a B5K pot.

Edit: I'd try an A10K on the Voice pot and see what happens.  Since it's wired backwards (you're getting the resistance between lugs 3 and 2) I think it should work like a forwards-wired reverse log, where most of the play on the pot will get you fairly high resistance.  I'll test this ASAP.

[oldhousescott]

Drop your Drive pot to a 100kB, and your Voice pot to a 2kB (or 5kB if you can't find a 2kB, with a 3k3 resistor strapped across lugs 1 and 3).

Haha, I was getting ready to post this, and once again Matt beats me to the punch! His suggestion for the log/audio drive pot is a good one.

[oldhousescott]

A reverse log on the Voice pot would spread out the upper range. The only potential problem is there seem to be fewer choices in values for reverse audio pots. A 10kC or 5kC will work if you can find one.

[mgwhit]

Yup.  I tested with my DMM.  Reverse taper works nicely for what you need on Drive.  I have struck out my bad advice (above), but left it in place so everyone knows I'm an idiot.

[frankie5fingers]

Matt and Scott, as always thanks much.  I could have just asked which alternative pot value would best serve my purpose, but I thought complicating it with a bunch of useless information would make for a more interesting read.
Thanks again, Frank