wah pedal thump/humping

[El Heisenberg]

I recently replaced the transistors in my vox wah from MPSA18s to BC109s and while doing so changed my Q resistor from 47k to 100k. I'm getting this click or hump or thumping sound in the sweep. Is this from the transistors or from the high Q resistor? I'm gunna change it to 68k, but I wanted to know if I couldn't go that high with the BC109s....even tho I think the Clyde wahs had them??

The thing is also true bypass and the emitter resistor is 390 ohms.

[El Heisenberg]

Oh yea and it has an output buffer using a J201.

[El Heisenberg]

well, I reduced the Q resistor to 68k and still get the thud in the sweep where the kink in the pots taper is. I guess it's the BC109s?? They're the old metal can type.

[Bullet79]

i'm having problem too with this 'metal can'... first i use BC109B then BC109C.. both were 'sort-off' useless... weak sounding wah..  discard em' and now with MPSA18 and 2N5088 and metal film resistor.... much better...

[El Heisenberg]

Did yours come with that red fasel inductor? I had to buy mine after I drilled through the original.


To be honest, I kinda like the BC109s, if it weren't for the hump. I don't mind the hiss. I kinda like being able to use it as a fake "wind" effect. And it sounds exactly like the end of one of my favorite Fugazi songs "The Kill".

THe hump sound isn't really that bad. I'll have to wait till the guitar guy comes and plays through it and I can play drums and listen.

[Bullet79]

got my fasel from smallbear... bit improve on the wah tone... fits my crybaby nicely with no mod...

[El Heisenberg]

yea, I forgot to mention, I think I liked the old inductor that came with the unit better. But it's hard to tell since there was like two weeks between playing.

I dunno know to describe it. But this inductor sounds more "closed" or goopy or gummy or small. The first one was open and nice and free sounding.

[Joe Hart]

Try the "midrange mod" (increase the 1.5K resistor). I did it and it seemed to smooth things out a bit. Not a ton, but a little. What worked best for me is moving the gear so that the wah moves a different portion of the pot. I have a "kink" in the pot and it was a little more than halfway towards the toe down position and I found it quite objectionable. I moved the pot gear so the pot went through a slightly different rotation and now the "kink" is in a place where I have a little more control over it, so it's not as noticeable. Hope one of these (or both) help!
-Joe Hart

[El Heisenberg]

I've already experimented wit every mod out there for the wah. Replaced inductor, Q resistor, mid resistor, gain resistor, and sweep cap. I already settled on values, but figured I'd have to change them when i put the BC109s in. Not much difference except a little volume drop, so I raised the gain and it was fixed. But there's that audible kink in the pot.

My mid resistor is 1k8 right now.

I'm thinking it might just be the old transistors or maybe I need a new pot. Cos nothing else it wrong with the thing.

[joegagan]

not to put a dent on anyone's aftermarket inductor sales,  but the red and yellow fasels of the last 8 yrs to current are just boring sounding to me.

new style fasel? sure it's a real pretty sweep, like a sonic rainbow , but not nearly lively or rude enough for my taste. already too many polite wahs in the world.

as you said, the dunlop inductors of late are often quite good sounding. vox as well of course.

el heis, can you put up a soundclip of the hump? sounds like the sort of thing i like in a wah. is it a little like this? ( listen to the wah guitar fills, ignore the new age strumming my exwife was doing.)


http://www.soundclick.com/player/single_player.cfm?songid=5068229&q=hi&newref=1

[Quackzed]

It may just be the pot....
though i get a thud sound when fully toe, and the metal foot piece thuds into the under enclosure... full to and full heel if the heel is whacking the base, i think the inductors can pick up the thud and amplify it, but if its in the middle of the sweep it might be the pot...
seems like wah pedals, due to dc on the pot i think, need pot replacement or get crackly faster than other pots...
just my two cents... it may just need a cleaning, maybee some piece of dust or oil got into the pot?!? when modding?

[El Heisenberg]

joe I cant watch or listen to that yet. Im on iphone and gotta wait till Im at a comp. i guess I should try to record the thing tomorrow.

Boring was the exact word I was using to describe the sound of the red fasel inductor compared to what came with the unit. I would never have changed it if I hadn't shattered it with my drill putting a dc jack in




Jeez, the pot may have gotten dirty? BAH! I heard alot about scratchy pots but I didn't think it'd happen so quick. If that;s what this is. And I think it ight be....tho it only happened right after I put the BC109s in.

[joegagan]

wah pots suck. useless, really. i could fill a bathtub with wasted pots from wah pedals.
but in your case, since the change happened directly after changing trannies, it probably is a gain related thing.

[El Heisenberg]

Well, I liked that wah sound. That track is alot like Yo La Tengos stuff, my fav band.

I didn't hear what my problem is tho in that wah. I'll start setin up to record directly to audacity.

[joegagan]

orale