Semi-DIY Wah Story / Hot Potz Taper Question

[Paul Marossy]

I bought a Cry Baby off of ebay last week for $20! I took the guts out and put my DIY Maestro Boomerang in it. Before I did that, I painted the shell a kind of metallic dark chocolate color and made my own name plate to put on the front. It looks pretty snazzy now and sounds great!

Now here is my Hot Potz question. The Boomerang circuit uses a 25K pot, and the Hot Potz II pots are 100K. Does anyone know what the taper is on those Hot Potz? I am hoping that I can solder a resistor in parallel with the pot and have that work as a linear 25K pot. Right now, I just have a RadioShack 50K Alpha pot with a 47K wired in parallel with it. I really want something tougher than that, though, because I use this wah the most and I expect that pot will be scratching soon...

Any help is much appreciated.  

[vanhansen]

I don't have an answer for you on the Hot Potz II but I just want to comment on how amazed I am at your DIY Wah's every time I look a them.  Amazing work.

[Paul Marossy]

I don't have an answer for you on the Hot Potz II but I just want to comment on how amazed I am at your DIY Wah's every time I look a them.  Amazing work.

Thanks. I put the Colorsound Wah guts in my second DIY wah shell last night (that used to hold the Boomerang circuit). Now I have the original one free for something else. I did learn that the pivot point is important - it's less fatiguing having the pivot at the heel end than it is at the midpoint of the foot paddle. For this reason, I like the second one I made better.

[nero1985]

cant you do something like the Scratchy pot mod? use an LDR?

just a thought, by the way you really kick ass making this pedal and its thanks to you tha ti learned alot of what i know about pedals! thanks!

you have schematics for that boomerang wah? ive never heard of it

[wui223]

I have a dumb question. Could we use a common pot and add the kinda gear of Hot Potz  to the shaft of pot. Which in turn would be like a Hot Potz, can we do that? and is it usable after all>?

[petemoore]

Gear wah shafts [at least on common wahs] are different than 'pot's shafts which are round.
 wah pot shafts are larger diameter, also have a 'set' for the gear, a flat 'side'.
 I gave up thinking about it after deciding inserting guitar strings between the gear and shaft till the gear rotated without 'cam' movement, then epoxying would be too much trouble and too risky.
 Small bear sells the gears if you want to mess with trying to align it to a pot...maybe a pot gear retrofit jig or something..lol.
 I put some together that use the sprung string method like EB Volume pedals, that way I can put Any pot in there.

[wui223]

Sprung string? Is it something like spring mechanism?

[Processaurus]

Wui, if you want to attach a gear to a non crybaby pot (for use in a crybaby shell), you can try sticking a small finish nail (the real small ones) through the shaft and gear, to hold it from twisting without the shaft.  Just drill a slightly smaller pilot hole in the pot shaft in the right place, and in a spot where it won't interfere with the part that turns it (the geared part attached to the rocker), and pound that baby in.  You do need a pot with a longer threaded part than the standard 24mm alpha ones I think- the bracket it tightens onto is real thick.  

Kind of a pain...

Paul, the LED/LDR pot might be a cool way to go, if you're worried about scratchiness.  Plus then it could be voltage controlled, if you're that type...
This page has some good ideas:
http://www.geocities.com/thetonegod/rockncontrol/rock.html

The DIY wah pedal you fabricated is really intense, by the way.

[sir_modulus]

remember also...when you do add a normal pot to that sort of gear...a hot potz is rated for a lot of cycles...a normal one isn't. The taper on the Hot Potz II is a log/anti-log (use either, wire either way)...but a lot more so. I believe the original was rather close to an audio taper, but didn't work all that well with the throw of the pedal, so in the new version, they made the taper "faster" (more extreme) to get more sweep in the small range of the pots rotation that's used.

I'm sure the parallel resistor trick would work fine in this case, because as far as I knew, it wasn't taper dependant.

Just my $0.02

Nish

[Paul Marossy]

cant you do something like the Scratchy pot mod? use an LDR?

Yes, I suppose I could do that Anderton mod to avoid that. I'd rather have a heavy duty pot, though.

you have schematics for that boomerang wah? ive never heard of it

I like it better than the Cry Baby / Vox wah actually. I'm not real sure how mine compares to a real one, though. Here's a schematic: http://www.montagar.com/~patj/mboomer.gif
I used a yellow Fasel inductor, 2N5089 transistors and 1uF tantalum caps.

I have a dumb question. Could we use a common pot and add the kinda gear of Hot Potz to the shaft of pot. Which in turn would be like a Hot Potz, can we do that? and is it usable after all?

Yes, you can. That is exactly what I did on my Boomerang clone. All you have to do is file the pot shaft a little bit to make a flat side for that gear to slip onto. I also drilled a little hole to put a pin thru the gear/shaft to keep the gear from going anywhere.

Paul, the LED/LDR pot might be a cool way to go, if you're worried about scratchiness. Plus then it could be voltage controlled, if you're that type...
This page has some good ideas:
http://www.geocities.com/thetonegod/rockncontrol/rock.html

The DIY wah pedal you fabricated is really intense, by the way.

Thanks for the link.

remember also...when you do add a normal pot to that sort of gear...a hot potz is rated for a lot of cycles...a normal one isn't. The taper on the Hot Potz II is a log/anti-log (use either, wire either way)...but a lot more so. I believe the original was rather close to an audio taper, but didn't work all that well with the throw of the pedal, so in the new version, they made the taper "faster" (more extreme) to get more sweep in the small range of the pots rotation that's used.

Exactly why I would like to have a heavy duty pot in mine. The 25K audio taper works really well with my DIY Boomerang.

I will be posting pictures of the rehoused DIY Boomerang wah tonight.  

[al3151]

Maybe you should look for Lo-Z volume pedal pots.There are usually 22K and 25K pots in expression pedals for keyboards,although I don't know what taper.

[Paul Marossy]

Maybe you should look for Lo-Z volume pedal pots.There are usually 22K and 25K pots in expression pedals for keyboards,although I don't know what taper.

Hmm... that's an idea.  :idea:

[Paul Marossy]

OK here's a few pictures:







I can't seem to get good pictures of what it really looks like, but it will give you an idea. I forgot a "guts picture", I'll do that tomorrow. I'm going to bed now!  :wink:

[jimbob]

made my own name plate to put on the front

I thought i was the only one that thought that one up! O well. Im in the process of sanding down a dunlop enclosure for the rotovibe i have that i aquired without the enclosure. Im painting it metalliz red- daker but fancier that the regular dunlop roto color.

[Paul Marossy]

OK, here's the guts shot and a better pic of the nameplate. When I built the circuit initially, I was thinking ahead to the possibility of it going in a future enclosure, and it worked out pretty well for "off the cuff engineering".  :wink: