Homebuilt Dunlop Wah- No Wah?

[jonathan perez]

why are you using a .001 cap?

[vfr800fiman]

why are you using a .001 cap?

It's on the schematic:
http://www.geocities.com/j4_student/crybaby.gif

[Paul Marossy]

That schematic has always perplexed me. The original wah used 0.22uF caps, not 0.001uF caps... 

[alderbody]

I don't think there is much of a difference between the 4uF cap and the 4.7uF cap, but some people hear a difference. To me, it's not enough to be overly concerned about.

Here's what i found about 4uF caps:
http://www.diystompboxes.com/smfforum/index.php?topic=46526.0

The difference is mostly in the way the effect operates and not in the way it sounds.

[alderbody]

I guess I just don't understand why the volume is reduced so much after it passes through the
.001uF cap.

maybe it's a bad cap... Did you try another one of the same value?

Can I still use the 2N3904's and change the rest of the components to the VOX circuit? or do I have to also switch to MPS-A18's?
I would assume the bias is different for these xsistors, so maybe I have to change the resistor values as well?

You can try anything that sounds good to you, as long as the specs match...  (mind the pinouts!!!)
For insatnce, i use a NPN Ge transistor for Q1 in my wah and a BC108 for Q2, and i didn't have to change anything else.
I put sockets so i could try some until i found the ones that sounded best for my setup.
Maybe you could replace Q1's emitter resistor with a trimpot so to adjust the gain of Q1. (lower values raise the gain)
btw, MPSA18's sounded really flat to me...

If i remember well, Q1 should be around 200Hfe for best results. (read R.G.'s article)

As for the inductor's resistance the 30 Ohms is the key...
I have a Fulltone inductor which is around 30 and it's awesome, while my Banzai is below 30 and it's not as chuncky as the Fultone.
btw, i use them both in my Wah, interchangable through a DPDT switch.

[moody07747]

If it were me, I would dump that 0.001uF cap and use a 0.22uF - it'll sound fuller that way. I don't think there is much of a difference between the 4uF cap and the 4.7uF cap, but some people hear a difference. To me, it's not enough to be overly concerned about.

I just picked up a original crybaby...

only thing i dont really like is the tiny movment in the sweep....i have to do something about that

anyways im going to swap that .001uF to a .22 for my first mod.

[vfr800fiman]

I guess I'm going to swap over the .22uF cap. as it seems like everyone agrees on this value.
I always socket my xsistors using SIP sockets trimmed to 3 positions, works great.

Thanks for all the suggestions. I'm going to look at a few of these things this weekend.

This board has always been great in helping me troubleshoot!
Thanks again everybody.
Glenn