Scratchy wah

[RickL]

Rather than re-open an older thread I thought I would start a new one.

I've been asked to repair a wah with what sounds like a scratchy pot. It only scratches when a signal is going through it and the pot is moved quickly. Damping the strings on the guitar and moving the pot quickly causes no scratching sound.

I think that I should hear the same noise with no signal if the pot is the problem so I'm hesitant to replace the pot if there is a less expensive (and more effective) solution. Searching earlier posts indicates that replacing the electrolytic caps may solve the problem. I'll try that, or replace the pot, if no one has any other suggestions.

[thermionix]

What kind of wah is it?  Can you read any DC voltage across the pot?

[RickL]

It's a Dunlop Bass Crybaby. I don't actually have it in my possession so I can't measure the voltage. It's at a music store that I regularly do repairs for and I don't like to take them home unless I actually have some plan for what I'm going to do.

I'll pick it up the next time I'm there (tomorrow) and do the measurement.

[RickL]

Okay, so I got it home. No voltage across the pot, but I can hear the scratchy sound even with the strings on the guitar damped or the volume on the guitar turned all the way down. It looks like the pot will need to be replaced after all.

[thermionix]

Yessir.  I have coming in the mail from Small Bear one of the Chase Tone sealed types.  Haven't used one before, but the long life expectancy and good price convinced me to try one.  Will find out how the taper is once I install it.  The demo at the Chase Tone website sounds cool.  Don't know if a bass wah calls for the same value (100k).

[stallik]

I look forward to your report on the chase tone pot. Ignoring the mojo statements about the device, it looks physically smaller than the hotpotz sealed units. 

[italianguy63]

Bass wah is the same-- just a different capacitor value in the circuit.  I have good luck with the HotPotz OEM pots.. they are pretty indestructible. 

MC

[Mark Hammer]

Stabilant 22 can work wonders on scratchy pots, and other mildly eroded contacts.  The caveat is that since it remains vicous for the life of the product, you can't build up layers.  So if a constantly-used pot is mildly eroded, it will fill in the pits and micro-discontinuities, and make it behave as new.  If the resistive strip is seriously worn, the application of a singlelayer of the stuff won't be enough to bridge the gap between wiper and strip.

[thermionix]

I look forward to your report on the chase tone pot. Ignoring the mojo statements about the device, it looks physically smaller than the hotpotz sealed units. 

Dang, a report?  Now I have an assignment, lol.  I currently have one of the "open" CTS-made pots in my wah, and even with the dust cover I've had to clean it several times in its 10-month life.  Also not 100% in love with the taper of it, maybe the Chase Tone will be a better fit for my foot.

[thermionix]

I look forward to your report on the chase tone pot. Ignoring the mojo statements about the device, it looks physically smaller than the hotpotz sealed units. 

Got it.  Installed it.  Love it.  I thought I had a taper issue with my other pot, now I know I had a taper issue with my other pot.  This fixed the last thing that was bugging me with my Clyde clone.  It's perfect now, for me.  They aren't kidding about the "vocal" thing, this taper really nails that.  Bwaahhh.

I like that it's sealed, keeps out the cat hair and whatnot, less worry.  It seems well constructed, and it turns very smoothly.  It is a little smaller than a HotPotz, but with the gear, bushing, washers, and solder lugs, there's really not a whole lot of space savings.

[stallik]

Good report thanks. I'll order one

[Kipper4]

"I like that it's sealed, keeps out the cat hair and whatnot"

I'd heard of the UVICS but never of putting the cat in a wah shell........

[thermionix]

(...googles UVICS...)

Ah yes!  Something that should be done.  I'd like to build one someday.  Expression pedal speed control seems ideal, like a Leslie, and all in one box even better, but I don't think I'm quite up to UV level yet.

[Paul Marossy]

I have a Dunlop Hot Potz II in my Fasel equipped Italian made Vox wah - I have no complaints and I like that the thing will outlive me. All of my wah pedals have their own personalities, I don't try to make them all work the same. Once I get used to them it's not a problem for me whatever pot they may have in them. The one pot I thought sucked was the original Hot Potz.