Has Anyone built this wah?

[MattAnonymous]

I've tried for the last couple weeks to build the Basic Wah Circuit found at http://www.geofex.com/Article_Folders/wahpedl/wahped.htm .  I can't seem to get it to work I was wondering if this was a working schem or just an example for reference.

[MarkB]

Matt (just up the road from me!)
Yes - that should be a workable circuit.. I believe it's a standard wah (twin-t?) design which is what the crybaby/vox are based on.

What kind of problems are you getting?  what parts are you using?  getting sound through but no wah?  have you tried using an audio probe?

debugging is the fun part.
"-)

[MattAnonymous]

I'm using an RS transformer for the inductor, 100k audio taper pot, for the .22uf caps I had to piggy back 2 .1uf caps, 2n3904's.  I'm getting sound but no wah.

[MarkB]

Hmm..
I'm kinda busy this evening (and I have nothing to use as the inductor) or I'd throw it on the breadboard... hopefully someone can test it out for you, but I'm 99.9999% sure that the schematic is right.

double and triple check how it's all connected..!
"-)

[RDV]

I built mine about a year ago using this circuit. It works perfectly. I used a red fasel inductor, and I highly recommend it. I'd also use the correct .22uF caps also and check your wiring.. This was my 1st circuit that I built also, and I'm proud to say that it worked with no debugging.

Regards

RDV

[Aharon]

The RS transformer does not work most of the time,trust me ,I've tried a few of them with the same result.
Aharon

[Mike Burgundy]

Just for the record: the standard vox-type circuit and a twin-T are two different beasts.
Are you getting no change in sound whatsoever? Or a volume change? *any* change in tonality at all?
I have no experience with the RS transformers, but I have wired up a couple of different old salvaged ones (from phones, radios) and at least got them to work, if not with very satisfying results..

[MattAnonymous]

How can RS transformers work some of the time when they're mass produced and identical?  The first time I built the wah I was getting volume control with no wah so I rebuilt the circuit and I'm not getting any sound change and I have to connect the grounds for the jacks together.  If I connect them together through the ground I get nothing.

[Aharon]

MAtt,man,I know they are mass produced but you should get a real inductor for whas,I'm telling you I tried many and none worked.I said "not all the time" cause the article at RGs states that it works and I believe him,so the only logical conclusion after my own tests show 100% failure rate is that they work....... SOMETIMES.I've built 2 whas from scratch and they both work so trust me on this one.Also people say that the inductor must be 500 to 600mH to work.........NOT!.......,my best wha uses a 200mH TDK and it kicks as$
Just trying to help
Aharon