Crybaby (inductor-based) wah HELP PLEASE

nandrewjackson · Post by **nandrewjackson** » 06 Nov 2015, 02:30

Hello,
I'm new to this forum, but not new to building electronics. I've successfully built several 12ax7 based preamps, a few EL84 vox style amps, and a couple El34/6l6 fender style amps. I've also successfully built a few pedals, simple bjt boosts, op amp buffers, a couple tubescreamer clones, and one "Keeley" four knob compressor "ROss" compressor.

I'm working on a crybaby wah circuit, in a standard pedal housing, to use as a "filter" pedal. I can get the circuit working, but can't get an unwanted fuzz clipping out of the circuit.

http://www.montagar.com/~patj/crybaby.gif

that's a link to a schematic, there are also a lot of others with nearly identical components and values.

when the guitar is strummed hard, there is a fuzz-clipping that I want gone from the circuit. I've used several different transistors, 2n2222, bc549, 5088's, and others, with basically the same performance. I've also tried changing the emitter resistors of both transistors, both higher and lower values, and tried higher and lower values of almost all of the other components. I'm using the dunlop red fasel inductor, I've learned that they're very heat sensitive, and burned one up, but that's not the issue, for when the one burned up, the "wah" factor simply disappeared.

I can get the circuit working, with great wah "honk", and driving it with a distortion pedal is GREAT, but I can't simply play clean guitar through it without being ultra light on the guitar pick without getting this unwanted clipping.

Is this normal with wah circuits? I owned a crybaby many years ago and don't remember the clipping, but I wasn't much of a tone freak then, so I don't remember much about it.

thanks for any info.

nandrewjackson · Post by **nandrewjackson** » 06 Nov 2015, 02:36

also to note,

I've built the circuit at least twice on a breadboard, and three times on perf board, with the same results every time. I'm so stumped .

grrrunge · Post by **grrrunge** » 06 Nov 2015, 09:36

Are you sure you have the transistor pinout right then? Different manufacturers may have different pinouts for the same transistor model.
A BJT with the collector and emitter interchanged should still work, but with much less gain.

nandrewjackson · Post by **nandrewjackson** » 06 Nov 2015, 23:41

thanks grrunge.

I've tried the pinouts different ways, I have the data sheets for my transistors, and I use sockets so pinout changes and transistor swaps are relatively easy.

I've been searching for info on the input and output impedences of this circuit, and well, all circuits.

the concept of impedence, with active components kinda fries my brain circuitry. resistance, capacitive reactance, current (electron flow) , and voltage, I can wrap my mind around those, but when these "impedences" walk through the door, something goes "poof" upstairs.

(not to mention conventional flow of current - from high voltage to ground - I can hardly agree with that one either. )

I"ve seen a lot of mention about crybaby circuits really needing both input and output buffers, so that may be the next move over here. the buffers , I gather, correct , or at least assist, in correcting the impedence of the wah circuit.

oldrenegade · Post by **oldrenegade** » 08 Nov 2015, 18:46

Don't know a great deal about how this circuit works but the .001uf caps at the Hotpotz pot are wrong and should be 0.22uf (as in the McCoy) or .1uf anyways. Whether that will filter out any of your fuzz I dont know but I'd experiment.

nandrewjackson · Post by **nandrewjackson** » 09 Nov 2015, 02:26

I got the fuzz out.

here's what I ended up with

<a href="https://s987.photobucket.com/user/nandr ... h.jpg.html" target="_blank"><img src="https://i987.photobucket.com/albums/ae3 ... %20wah.jpg" border="0" alt=" photo noahs dual filter wah.jpg"/></a>

I used a 5457 jfet buffer I got from guitarfxlayouts and put one at the input and one on the output.