Vary Re1 up or down A popular mod is to temporarily replace Re1 stock value ohms with a 1K linear pot. As the resistance is decreased through the original value towards zero, the sound starts getting richer, as a consequence of the first transistor's gain going up.
The increase in gain is accompanied by a modest increase in distortion, accounting for the fatness. When the resistance gets near zero ohms the wah will be at or near self resonance, and will self oscillate at the low end of its range, then wah into notes as you rock forward on the pedal.
Touchy, but cool! As the resistance of the pot increases above the nominal value the sound starts to get less "wah-ey" as the gain of the first stage drops and the feedback can't make as peaky a resonance. You can either find a value you like and put in a fixed resistor with that value, or mount a pot somewhere you can twiddle it.
Change the Rq to change the "sharpness" of the bandpass. If you change the value of Rq, the nominally 33K resistor parallel to the inductor, you change the sharpness of the resonance. Larger value resistors narrow the resonance band. Smaller values damp the resonance more and spread out the resonance band but make it less peaky, so the effect thins out. Some people swear by values like 51K as being incredibly good. This trick will let you either cure a scratchy pot which is what Anderton originally proposed it for or put the rocker pedal arbitrarily far away from the wah circuit.
To do that, just remove the circuit board from the inside of the wah, being very careful to note what connects to what so you can undo this if you want.
Neat diagrams help! Then make up a cable with shield and two wires in it. The shield carries ground. I did this with a Vox Reissue, and it worked great. There is still this little problem of how do you bypass it then, but I have to save some secrets. Here are two ways to make a voltage controllable wah. In both cases, the actual circuit relies on a transistor to take the place of the LDR in Anderton's wah retrofit.
The first uses a P-channel JFET, which is on low resistance when its gate and source are at DC ground, and goes progressively higher resistance as the gate is taken more positive than the source. In this case the resistance is highest when the control voltage is low, and gets lower as the control voltage feeds a trickle of current into the base of the NPN. Tone Sucking loss of treble in the bypassed position The bypass switching in wahs up through the mid 90's used an SPDT switch.
The switch does not provide for true bypass switching, so the input of the effect is connected to the input jack at all times. This means that the wah pedal input loads down the guitar signal, and worse, loads it more at treble frequencies than at bass frequencies. The sound gets duller and less lively.
There are two cures, and they work about equally well. First, you can put in a DPDT true bypass switch. Second, you can add a buffer in front of the wah to keep it from loading down the guitar signal.
There is an article on how to build the buffer onto the internal wah printed circuit board at GEO. Pot wear With all the rocking back and forth that a wah pot gets, it gets more wear than any panel mounted control ever does.
The mechanical slider that moves over the resistor element inside literally wears some of the material loose. This material can collect in ways that can cause the slider to lose contact with the resistor material, and when that happens, it makes a "scrackle" sound as the pot is rotated. There are two cures: either a clean the pot or b replace the pot.
Cleaning the pot should be regarded as a stopgap measure. It will help for a while. Go to a Radio Shack or an electonics supply house and get a spray can of "tuner cleaner" or "electronic contact cleaner". Spray this into the pot while rotating the pot shaft. The scratchiness should be much better. Geoffrey Teese has advised people to spray inWD after using tuner cleaner on the theory that the cleaner dries out the factory applied lubricant and WD is a reasonable replacement. There are tuner cleaners that say they leave a lubricant on the surfaces.
Some people swear that any lubricant will accelerate the deterioration of the pot. The right thing to do is to consider cleaning as a temporary measure and replace the pot. Replacement pots are available from several sources. Fulltone sells a similar pot. Some people think the replacements sound better than the originals. The schematic has already been shown under "Mods". This replaces the wah pot with a fixed resistor and LDR, and uses the original pot only to change the current on the LED.
It works, and it's very smooth indeed. The original pot will then last until it develops completely open spots. Loss of signal level After putting in a true bypass switch, people often find that they lose a bit of volume when the wah is kicked in. This comes from one of two places; either the forward gain of the wah circuit is a bit below one, or the loading of the wah circuit cuts the guitar signal down a bit.
You can correct for this by lowering the value of the 68K input resistor somewhat to 33KK maybe to increase the gain. Notice that this also lowers the input impedance and may change the tone of the wah in the effect setting.
The bypass setting will be unaffected because of the true bypass switching. No "wah" sound, only volume change Cbp is failing. Replace it with a new 4. The input impedance of the effect is loading down the output of the wah, as the input impedance of the next effect appears effectively in parallel with the collector resistor of Q1.
This directly cuts the gain, which we've seen is responsible for the variable-capacitance effect that gives the wah its variable-frequency sound. The solution is pretty simple - buffer either the input of the following effect or the output of the wah. Let me start this with advice - don't do this, at least not the classic foot operated rocker pedal. It's not because the electronics are hard.
They're not, they're almost trivial. You don't even have to come up with any super special parts, excepting the inductor, which we'll cover. Rather, it's because making a reliable foot-rocker pedal to turn a pot is HARD.
If you're a good machinist or tinkerer and also play a guitar, OK, go for it. Otherwise, buy a dead Crybaby and refurbish it. The rocker pedal mechanics is not something to attempt lightly if you don't have the tools to do the metal work.
I often find repair shops have a pile of dead Crybaby shells in various states of cannibalization that they will part with fairly cheaply. You should consider making the whole mechanical setup only if you have no other good options.
The electronics isn't too hard. Perfboard works well, and PCB's aren't too difficult to make for this one. I recommend getting your mechanical packaging settled first, then making sure that the board you're going to build it on fits in side the mechanical packaging properly. Do this before putting parts on the board. Beyond mechanical packaging of the pot rotation setup, the critical issue for wah builders is finding a mH inductor. There are several ways:. A much less mysterious circuit is the twin-T style wah.
The naming of the twin-T is reasonably obvious from looking at the circuit. There is one "T" composed of two resistors in series and a capacitor to ground. The second T is made of two capacitors in series with a resistor to ground. The T's are hooked in parallel. They're not exactly twins, but close enough for naming. The twin T network all by itself is a notch filter. As a sidelight, it's about the only circuit composed of only resistors and caps that can have an infinitely deep notch - that is, if you tune the values of the R's and C's perfectly, the frequency at the notch of the filter will be completely removed.
Most applications don't need this perfect tuning, and in particular wahs don't. To get a bandpass humped response, we use the twin-T network as negative feedback around an amplifier.
I'm going to try to start playing guitar at the rehearsal next week. Hopefully my fracture has healed up by then. The sutures on my biopsy on my left leg hurts, but not as bad like last week. That's really cool that you did some mods on your Crybaby 7 years ago. I would like to know what components you've changed and what values do you prefer. You're ahead of me, in terms of experience and knowledge. You've also got to colloborate with the master of all wah pedals, Geoffrey Teese. I just wish I could buy a Teese RocPot and wah inductor from a used wah pedal.
I better start looking on E-bay. I started modding my 2 Dunlop Crybaby and 1 Vox wah pedals about a month ago. I decided that I wanted to do improvements on my Vox wah pedal, but would find a Crybaby wah pedal as my platform for experimentation. The 2nd Crybaby wah shown in this thread was stock and non functioning.
I've decided to implement Mollers wah mods to see if they would work. I swapped out the 4 resistors and 1 capacitor already mentioned.
The resistors that I swapped out improved the tone of the Crybaby immensely. The capacitor mod wasn't quite what I wanted.
I will buy 0. The 0. It lowered the wah's sweep frequency too low for my liking. It would work great with another capacitor and pot for an adjustable sweep. I'm not sure about capacitors types or values. I've only started to experiment with changing 33K, 1.
I'm a newcomer when it comes to this sort of thing, but I'm happy to share the outcome of the "Pimp My Wah Pedal" experiment.
If you have information that you would like to share with me about wah mods, post it here on the messageboard or e-mail me. Hey people, What's up?
Here we are again with another posting of the "Pimp My Wah pedal" project. I've done the mods suggested in Andreas Moller's website. The resistor mod changes improved the sound of my Crybaby and Vox wah pedals. I ran across an effects website called Fuzz Central hosted by Phillip Bryant. He has a really cool article called the Axis Wah. He even shows you how to build a buffer circuit as well. Very cool!!! The most valuable information that I learned from this article was changing the transistor values.
I wasn't aware of changing the transistor values although I've seen people mention a certain transistor value on this messageboard and the Gear Page. The transistor value that was recommended was the BCC. They even provide a. PDF file to show the specifications of the transistor. I used the 2N I unfortunately installed them the wrong way on my Crybaby wah and asked for Brad's help in selecting the correct transistors and the installation of the new transistors.
Here is a picture of our Saturday night project:. If you don't, you could over tighten the screw and pop the head off. It doesn't really matter if it is a Phillips head or flat head.
This isn't really very good for the potentiometer and may cause early failure. However, in a pinch this might work. As something of a last ditch effort, the case can be fully dismantled, the flat spring turned around degrees so the built-in angle falls in a different place , and then all reassembled. The "flat spring" is the metal "strap" that runs over the axle which attaches the rocker to the base. The flat spring is what exerts added pressure as you tighten the nuts mentioned at the beginning of this section.
A little goes a long way. Raise the switch action by lowering closer to the switch body the round nut. Finger tighten the top hex nut and try it out. Should there be any issues with your order, please contact us and give us a chance to make it right, prior to leaving any negative feedback or online reviews. We promise we will make sure you have a positive experience. You are the man.
I thank you so much. I really like the sweep attack. It really is a sweet pot! Awesome pots! You sir, Nailed It!!! It sounds very, very vintage and as if already played in. When toe down, there is not the slightestunpleasantness.
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