Help W/ Roger Mayer wah please!

[ethanw]

I've had this wah forever and it's my favorite, sounds great! It's a Dunlop that had a Roger Mayer kit installed by North Star Audio in the 90's. Unfortunately, it has a weird problem: when playing, the sound seems to drop out right at the peak while moving the pedal back and forth. Other times it seems like there's a staticy sound right in the same spot. The tone is correct and it bypasses fine, just when you move thru the sweep something screws up at the critical spot. Pot is a new Fulltone, 2nd one I tried so it's not the pot. I true bypassed it years ago, think i did it correctly. Circuit-wise, it looks like a stock Clyde with a buffer. It also has an adjustable gain pot and a coil tap for the inductor. Any and all replies are welcome, i'd love to get my wah sounding right again!

Thanks in advance- Ethan

[jonathan perez]

coil tap for the inductor? im not sure what that means.

[ethanw]

It's the only wah I've seen it in. I guess it's just like a tap on a single coil humbucker. Could be wrong though, I thought I read that its a tap on some of the earlier documntation. This is the switch with the yellow, blue and white wire at any rate.

[Pedal love]

Carbon film resistors, can add noise in this circuit. Thats why Roger moved to all metal film.pl

[Dai H.]

maybe check over some of the solder joints. The ones around the footswitch look a bit crappy. I'd suggest making a little hook like you see on the other ones to make sure the wire doesn't move when the joint is made(movement when joint is made = iffy or cold solder joint). The North Star workmanship looks pretty good far as I can tell. I have a board also and it looks a bit different.

[ethanw]

More info: mods were done in '91. There's 2 electrolytic caps on the board, the larger is a 220uf for the power supply I assume, the smaller one is a 2.2uf. Seems to me most wahs have a 4.0 or 4.7 uf here. I might swap it out as I can't think of anything else that could be wrong.  I'm going to resolder the connections on the switch just to be sure-

[tcobretti]

If the pedal was working correctly and then stopped for no apparent reason, I would replace the electrolytics, and if it still didn't work I'd replace the inductor.  They are the most likely things to fail.   The next thing would be to check the gain pot and the coil tap switch.  If the pedal stopped working after being recently modded, then obviously the mod is suspect.

I'd also disconnect the rack and pinion so the pedal no longer moved the pot, then manually twist the pot to find the bad spot and use a multimeter to verify that the pot is indeed working right, and I'd check the transistors' voltages while I was at it.

[jonathan perez]

^^^^^ +1

[Geoffrey Teese]

Hi Ethan,

Don't replace the inductor - it is not broken (accorcing to your text) and you will not get an inductor wound like that from anyone but Roger.  I agree that all "new" work be closely inspected for faults.  Did the wah have the noise(s) before you changed pots?  I haven't touched one of Roger's wahs in well over a decade but the very first thing I would do would be to replace the existing pot with one of the blue Lifetime/Long Life pots as that is the pot Roger designed the circuit around.  Some wah circuits are VERY sensitive to the type of wah pot taper.  Using the wrong taper in one of "those" circuits results in the static and pops that you've described.  I wouldn't even consider changing an electronic component until the proper wah pot had been installed.

Good luck.

Peace, Love, and Wah,
Geoffrey

[tcobretti]

Ethan, I feel very comfortable saying that Mr Teese knows more about wahs than any of us who trying to help, so I would take his comment very seriously. 

I think the key issue here is whether the problem in associated with any mods.  Did you put the original fulltone pot in and then the problem started, so you replaced the pot with another like it?  If so, then the type of pot certainly seems suspect.  If, however, the pedal had been working fine for some time and then just started malfunctioning, I would check for pot failure first (probably even just replace it since Mr Teese recommended it), then I'd check the other pots and switches, then finally I might try replacing the electrolytics (kind of a last ditch effort).  Since Geoffrey disagrees with the inductor, I'd leave it alone.  It was just a guess on my part anyway.

[ethanw]

Thanks for all the input guys! Here's the deal, I true bypassed it a few years ago, then didn't play it much, probably changed the pot at that time. I think it sat for a while, then I went to plug it in much later and it seemed funky. So it's hard to pin down if it's the bypass, I double and triple checked the bypass wiring, I'm pretty sure it's good. I just swapped out the 2.2 uf as I had one handy, no help. The exact symptom is this: it bypasses fine and has a good wah tone, but has a dead spot right in the middle of the sweep. So you'll play with the pedal back, slowly sweep forward, it will sound fine, then the volume will drop out to virtually zero in one spot, then return thru the rest of the sweep, still sounding fine. Geoffrey, thanks very much for your input. This wah had the original Dunlop pot stock, being the large sealed silver unit, maybe an ohmite or similar.  I buy Fulltone pots in bulk, this one is the second brand new one from 2 different batches. I doubt the pot itself is bad, but it may well be the taper as GT suggested-

Ethan

[tcobretti]

So, the dunlop pot worked fine but the fulltones are 0 for 2?

That backs up Geoffrey's diagnosis.