Wah pot scratchy when stepped on?

[AC30Dirty]

hey guys, maybe you can help me out with this? I have a modified VOX V847 that I absolutely love. I recently installed a Black Top Pro Pot in it as well, but I've noticed that when I rock the pedal it makes a slight scratchy noise. Just out of curiosity i opened up the pedal and took out the pot and turned it with my hand and there was no scratch what soever. So I installed it again and tried it out; and there was the scratch again. I can't figure it out. ANY SUGGESTIONS?

[chunks717]

pot ground rubbing enclosure some how maybe??......or giggling a bad solder joint somewhere else?......
if its not the pot its *not the pot*......or something like that.....

[AC30Dirty]

It only makes the scratchy noise towards the toe-down position. if this helps any?

[warioblast]

It only makes the scratchy noise towards the toe-down position. if this helps any?

Did you find out what was wrong ?
I have just finished my custom wah and I have exactly the same problem. My pot is brand new too.
The scratches appear when I play on the clean channel of my amp. When I'm playing on the lead channel, the wah doesn't crackle .

[AC30Dirty]

Thats exactly what mine did warioblast. It was really anoying me I went ahead and changed the pot to a Hot Potz II (which i was surprised by its exceptionally smooth rotation, almost like a pro pot) and the problem went away. The only thing i can think of is i heated it to much when i was installing it. I would like to try and put another propot someday.

P.S. also where in the rotation does it occur?

[warioblast]

Just like you, the crackles appear when I reach toe-down position. It's a brand new Banzai ICAR taper pot. I don't think heat is the problem as I quickly made my solders, and my old pot which is the Dunlop hot Potz II have suffering way much iron solder assaults and it still working fine.
I'll put the hot potz back in tomorrow and see how it goes.
I hope I'll quickly fix it, because so far the wah sounds pretty good, the Ariel Fx Halo inductor has a nice qwack. My biggest surprise is the noise ratio between metal film resistors and the carbon film ones (taken from my old dunop GCB 95) I previously used in my old DIY wah.

ps: what did you put on the pinion gear, rack gear and its support to avoid frictions ? Vaseline doesn't work for me.

[warioblast]

I have just replaced the Icar pot with my old dunlop hot potz 2 and crackles went away. 
I'll try to clean the Icar with some Deoxit but I don't think this will make a change. 

[lacto]

Those Propots or Propot copies are ridiculously sensitive to heat.  For grease you need to use lithium grease which you should be able to get in a big tube (lifetime supply) at a hardware store or Home Depot etc.

[AC30Dirty]

Hey Warioblast, I tried out two wahs the other day. A wah that belongs to a friend on mine and my wah. They have the exact same circuit and mods done to it, the only difference is the pots in the wahs. Mine has the HOT POTZ II and his has the FULLTONE. We both agreed that the HOT POTZ II sounded better. They actually have almost the exact same taper also, the only real difference is the actual feel of the pot. If  you go to the Area 51 web site and look under parts for a wah and go to the HOT POTZ II they have a link on that page where the compare the Fulltone pot and the HOT POTZ II with a chart the the sweep frequencies as well.

http://www.area51tubeaudiodesigns.com/pot_taper_charts.htm

[warioblast]

I put the Pro Pot back in this afternoon. 
Before I took off the black plastic cover and sprayed some bursts of Deoxit. And it worked !! No more cracklings 
The Hot potz II is definitely quicker than the Pro pot, I now need to set my "mid" trimmer.

[Mark Hammer]

Pots are scratchy because of intermittent contact.  Intermittent contact, in turn, can occur because the contact between wiper and resistive element is physically obstructed by dirt or other obstacles, or it can occur because there is a gap of some kind between the wiper contacts and other surfaces.  When you press on a foot treadle, in some instances that can place lateral pressure on the pot shaft and budge it ever so slightly off the perfectly perpendicular.  Moving off the perpendicular can result in the wiper lifting off a couple of microns.  The physical space may be small, but the gap is created just the same, and we hear it as crackle and scratch.

Deoxit or even just a wipe-down with a Q-tip on the bare exposed resistive strip can help get rid of grime and physical obstacles to contact continuity.  But it can't fill in any gaps between contacts, and after the wiper contact scraping the surface of the resistive strip a few thousand times, you probably do start to get erosion of resistive material.  Happily, the spring-leaf aspect of the wiper applies some pressure to maintain contact, but that will only take you so far.

This is why I have been raving about this Stabilant stuff.  It forms a stable conductive layer on top of the resistive strip and fills in those extra few microns to reduce contact discontinuity.  You need to pop the back off the pot to apply it directly to the resistive strip and wiper, unlike simply spraying incontact cleaners via a tube, but hot damn it works.

The other thing that can sometimes happen is that thesolder lugs are not riveted tightly enough to the phenolic (or other material) part of the pot where the resistive strip is mounted.  Those lougs grip the two ends of the strip and sometimes it isn't tight enough.  A little pinch with the needle nose can sometimes tighten up the grip a little and improve reliability of contact.  Wouldn't hurt you to dab a few drops of Stabilant in there to fill in any potential gaps either.

I hate to keep goping on and on about this stuff, but it works and I know of no other comparable product.  Somebody find one for me and I promise to be less brand-specific in my comments in future.

[Paul Marossy]

I think the Hot Potz IIs are good pots. I prefer them over any of the other ones that I have tried.