I need a supplier for wah gears and racks

[Oatmeal]

I have a project in a wah enclosure that will push two wah pots but the circuit doesn't have a one to one ratio. I need a variety of pot gears and racks to experiment get the ratio right.
Anyone know where I can find a supplier of small gear parts that would be useful?
Sadly I don't have an oscilloscope to mathematically calculate the relationship of the two pots moving in unison.

[Oatmeal]

Update---
I am leaning toward using radio control car rack and pinion gears. They are aluminum which is cool.

Does anyone know the standard OD for wah pot shafts? I could bore the gears out if necessary but I'd rather not have to.

Also does any one know of a resource for some relatable graphs of resistance curves for available wah pots?

[Govmnt_Lacky]

Does anyone know the standard OD for wah pot shafts? I could bore the gears out if necessary but I'd rather not have to.

Usually, most wah pot shafts are 1/4 inch or 6.35mm

Also does any one know of a resource for some relatable graphs of resistance curves for available wah pots?

Try the Alpha Taiwan, Alpha USA, or Alps websites. They are common pots used around these parts and they have resistance graphs for their respective tapers.

Good Luck 

[Mark Hammer]

Antique Radio Supply carries them:  http://www.tubesandmore.com/products/P-ECB-RACK

[Oatmeal]

I guess I haven't been very clear as to the problem or what I'm doing....

I'm trying to put a distortion circuit in to a wah housing(not a wah). I believe that I can replace the drive and volume pots with wah pots and work out the gear ratio to where they are inversely related. So when you rock the pedal forward you get more drive and pull the volume back at the same time, thus maintaining the same overall volume. It's been an idea of mine for a log time and I'm just now beginning to get comfortable with stepping outside of the "kit" so I thought I'd give it a try.

This could be a cool effect and if anyone else wants to try their hand at it also that would be awesome. It would work for almost any distortion or overdrive but I'm sure the gear ratio or pot tapers would have to change.

I see a lot of trial and error in my future.

[R.G.]

You might want to do some thinking about linearity.

The obvious problem that hits me is that drive (and hence distortion) often does increase volume, but I think that's not a direct relationship. I believe more distortion increases volume less than linearly.

Hmm. Also, since what you're trying to do is ramp one up and one down, why not use one dual pot and wire one section to ramp up, the other down, when turned by the common shaft?

[Oatmeal]

I considered a dual gang pot but one pot would have to be reverse tapered and that would probably be almost impossible to find, especially since the ratio is not directly inverse.

[R.G.]

Two things occur to me. One, using a dual linear with tapering resistors may get you the forward/reverse tapering you need, as tapering resistors allow you to modify the taper to much more than simple forward/reverse. Two, if you've read "The Secret Life of Pots", you've seen some of how modern pots are put together. It is possible to disassemble two mechanically similar dual pots for the hardware and the wafers and reassemble them into two dissimilar-dual potentiometer units. I've done it.

I say this because I hate dinking with racks and pinions and such on pots. It's much easier (to me!) to disassemble and reassemble a dual pot than to make dual racks and pinions with various different ratios.

But that's just me.

[Oatmeal]

I wish I knew how to change the name of this thread to "Building a sweepable drive distortion into a wah enclosure."

And now I'm going to hijack my own thread...

I just realized that you are THE R.G. Keen and kinda got geeked out. I'm about to build my own pedal board in an old suitcase and use your Spyder power supply with 2 Weber transformers. The bottom tier will have the dieing battery option and the top will not for the modulation effects. This is a whole other thread I will need to start later. I'm adding a lot of built in stuff.

[smallbearelec]

I considered a dual gang pot but one pot would have to be reverse tapered and that would probably be almost impossible to find, especially since the ratio is not directly inverse.

Here is how I modded a standard expression pedal shell to accept a pot that is Not a "Crybaby standard":

https://www.smallbearelec.com/HowTos/Swell/Swell.htm

Might be applicable to what you are trying to do. Also, maybe there's way to have a single-gang pot drive a circuit that makes the resistance of one element (Vactrol?) go down while its companion is going up?

[Oatmeal]

I was posting as you were posting so not even this post is linear.
I will reread your article on pots and that may end up what I do. Every time (once lol) I've taken apart a pot it wasn't the same afterwards.

[Oatmeal]

Thanks smallbearelec  for the suggestion but I don't think I'm skilled enough to mod the actual circuit beyond tone shaping. As far as the link, I'm either building it out of an old Morley enclosure or a larger enclosure that I forgot what I bought it for. Either way there will be metal fabrication and possibly welding occurring. I can't bring myself to destroying my nonworking Thomas Organ wah.

[smallbearelec]

I'm either building it out of an old Morley enclosure or a larger enclosure that I forgot what I bought it for. Either way there will be metal fabrication and possibly welding occurring. I can't bring myself to destroying my nonworking Thomas Organ wah.

I didn't know that you had a chassis available and I surely would not recommend cannibalizing a classic Wah. If the Morley can be made to suit your purpose, great! If it would need a lot of tooling, I do sell the shell that I show in that article:

http://www.smallbearelec.com/servlet/Detail?no=548

as well as other bits and pieces. Good luck with your project!

Regards
SD

[Oatmeal]

R.G.,
I'm probably going to try using tapering resistors on a dual pot like you suggested. Do you have any recommendations of pot models that can be easily disassembled and where I could buy them? I could destroy a bunch of pots in this process but hope has mildly increased.

[pinkjimiphoton]

FWIW, the klon centaur kinda does what you're looking to do...

i like the idea of using photoresistors tho..add a couple trimmers, and you don't have to mess with the pots so much, i'd imagine
you could dial it up or down to whatever you'd need it to be.