Need help with my wah

Started by warioblast, January 24, 2006, 01:57:30 PM

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warioblast

Hi,
For a few weeks now, I have some "metallic" noises, like cracklings, when I strongly rock my wah. The noises appear at each end of the throw. I still have the bumpers on the front and the rear of the pedal, so there are no contacts between the 2 parts of the wah.
When I softly rock the wah with my foot, or/and when I slowly reach both ends of the throw pushing the wah with my hand, the wah is perfectly fine.
Has anyone ever experienced this ?
Cheers,
Fabrice

Mike Burgundy

Firts suspect is the pot, naturally. They wear out in time. BUT: if it doesn't crackle when rocked slowly, something like loose solderjoints might just be the problem.
Make sure the pot housing is tighly secured (so it cannot move when you're vigorously wah-ing), resolder all connections to it and perhaps try some contact cleaner.

warioblast

I finally took some time this afternoon to find out what was wrong. Yeah I know I'm pretty fast  :icon_redface:
The problem was that one transistor was a bit loose in its socket.

Mike Burgundy

tranny in a socket? was this a DIY build?
At leats the problem was mechanical - and a cheap fix, too ;)

warioblast

#4
Quote from: Mike Burgundy on February 17, 2006, 07:06:53 PM
tranny in a socket? was this a DIY build?
At leats the problem was mechanical - and a cheap fix, too ;)

Yes it's a diy wah. I cannibalized my dunlop wah, used the Clyde schematic and added an output buffer.
I received Ariel Halo inductor, Pro pot and all the components to make GGG mod-able wah but I'm still tweaking my board before putting the Halo inductor. I think I won't do the sweep mod and let the 10nf alone though.
I'll add a 1k pot after inductors to control Q (like the dunlop 535Q). I already tried that mod and the results were better than just playing with Q resistance value. You do really hear the wha to who thing.

Is it important to make a connection between ground from the board and the chassis ? I have a little hum when I step on my wah :icon_redface: that makes me think I have a ground problem.


warioblast

I connected the chassis to ground with a wire tied to the skrew that fixed the board to the chassis, nothing changed.

I added a switch for the ouput buffer. I might leave it off because I realized even cleans sound better with the buffer on. In fact I would recommend any wha users to add the output buffer as anything sounds better; clean, OD, disto, fuzz... with it.

I also added 2 sockets to the board (will add an on/off switch later). Now I can put a 10nf cap accross the inductor like the dunlop JH1 wah. To my ears it tamed a little the highs, making the sound smoother between highs & lows.
It sounded more hendrixy with that cap off, but I will keep that mod, surely another usefull one.

My future wah is taking shape  :icon_biggrin:




Paul Marossy

The inductors in wah pedals are very sensitive to picking up hum. Are there any sources of EMI nearby? Things like transformers, wall warts, CRT computer monitors, etc. I once had a major hum problem with my wah having feedback and hum with certain distortion pedals, and it was all caused by my wallwart being too close to the wah pedal. I put it on the opposite side of the pedalboard and the problem went away.

warioblast

Yes I found out that my CRT monitor was my biggest source for hum. But I still had some noises, I told you hum, my bad, but its was more like cracklings.
So I tried the wah without the bottom plate and those cracklings were gone  :icon_biggrin:  I had already shielded the bottom plate years ago with double sided adhesive tape but it starts to wear out.
What would be a less cheesy way to shield it ?


343 Salty Beans

Quote from: warioblast on February 19, 2006, 05:29:57 PM
Yes I found out that my CRT monitor was my biggest source for hum. But I still had some noises, I told you hum, my bad, but its was more like cracklings.
So I tried the wah without the bottom plate and those cracklings were gone  :icon_biggrin:  I had already shielded the bottom plate years ago with double sided adhesive tape but it starts to wear out.
What would be a less cheesy way to shield it ?



I dunno if this will carry over, but when I modded XBoxes, switching an inverter on and off made the XBox reset. The solution was to wrap the inverter in aluminum foil several times, which took care of the problem cuz it shielded the signal the inverter sent. I bet neatly wrapped aluminum foil would take care of your problem and be freaking shiny too ;)

PS: since I worried about shorts, I also wrapped the inverter in electrical or duct tape after the foil coating. You might want to think about that too.

formerMember1

QuoteI bet neatly wrapped aluminum foil would take care of your problem and be freaking shiny too

you mean the inductor? Isn't that what the metal can film inductor of yesteryear was or no?  <<<kust wondering,..

QuoteI'll add a 1k pot after inductors to control Q (like the dunlop 535Q). I already tried that mod and the results were better than just playing with Q resistance value. You do really hear the wha to who thing.

so you mean add a 1k pot in series after the inductor?  Does this provide a different tone then varying the Q resistor parallel to inductor, or just a  wider range of that mod?

warioblast

Quote from: formerMember1 on February 19, 2006, 10:58:06 PM
QuoteI bet neatly wrapped aluminum foil would take care of your problem and be freaking shiny too

you mean the inductor? Isn't that what the metal can film inductor of yesteryear was or no?  <<<kust wondering,..

QuoteI'll add a 1k pot after inductors to control Q (like the dunlop 535Q). I already tried that mod and the results were better than just playing with Q resistance value. You do really hear the wha to who thing.

so you mean add a 1k pot in series after the inductor?  Does this provide a different tone then varying the Q resistor parallel to inductor, or just a  wider range of that mod?

yes a 1k pot in series after the inductor. when I tried different values for Q Resistor, the changes were pretty subtle to my ears. so I would say that doing that 1k pot mod has a WIDER range for sure.

Paul Marossy

Quotea 1k pot in series after the inductor

I haven't heard of that one before. Sounds like an interesting thing to try...

warioblast

I got this idea from forumite Kusi.

He also posted a schematic of a custom wah he made, with other good mods to try, including bass (NOT the SWEEP mod) and treble controls.


formerMember1

Cool!

SO that actually changes the ohms of the inductor itself then?  In another thread someone told me to do this too. 

I didn't know i could do that without having it change the mH of the inductor,....

Paul Marossy

So that is apparently messing with the DC resistance a little bit? Or it's changing the "Q" of the circuit. Interesting.

343 Salty Beans

#15
Not the inductor, use aluminum foil for shielding the inside of the wah case if it's picking up hum from an outside source. Or, if you know it's a power supply or something, just shield that.

formerMember1

I tried a 40ohm resistor in series with my 30ohm inductor and didn't like it.  I think it messed with the inductor differently then winding it with more ohms in the first place.  I don't know though,...  ???