mound Posted January 12, 2004 Share Posted January 12, 2004 -------------------------------------------------------------------------------- Hi - I'm not sure which forum is best for this. I've read both of Anderton's projects for musicians books, great stuff.. Built a few of the projects within. A guitar player friend asked me "look in those books, see if there is anything to fix my Wah pedal".. Well, his symptons are this: His guitar signal (Les Paul) is fine through his chain of effects. When he inserts his "vintage" (it's old, not sure exactly how old) crybaby wah pedal, the signal is still fine - that is, until he switches it on. At that point, the wah still works, he says he doesn't get scratchiness when rolling on it, but he's seing a loss in signal strength "it just sounds thin when the wah is on".. Can anybody point me in the right direction for repairs? Maybe Anderton's buffer circuit placed before the wah? maybe it's just dirty? I've been scouring the net for "wah repairs" but haven't found anything particularilly useful. Thanks Paul "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 12, 2004 Share Posted January 12, 2004 Mound, Welcome to the forum! Electrolytic capacitors degrade over time. I'd look at replacing all of those first with new caps of the same value. Polystyrene or polyethelene caps look like green squares and ceramic caps look like a tan disc. They have a number on the side like 473, meaning 47000pF, 47nF or .047uF. The electrolytic caps look like little cans, and usualy have the value written in plain english on the side, like 10uF/25V. If replacing just the electrolytics doesn't do the trick (I believe that it will) replace the poly caps next. The ceramics don't wear out, as far as I know. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
Teahead Posted January 12, 2004 Share Posted January 12, 2004 Another thing to look for, which happened to my Wah recently, is the switch breaking inside the small steel screw casing that turns the pedal on. Sorry I can't be more technical in my description, maybe blue will help out her, but basically stomping too hard on the pedal, or in a vintage case moderately over a long period of time, causes the connection to engage, but not completely. The symptoms you describe from the wah sound identical to mine, engaging the wah resulted in a weakened signal. The good news is it was fixed for nominal fee by a local techie. Hope some of this helps. Tea. Pedal Clips Link to comment Share on other sites More sharing options...
baronedo Posted January 12, 2004 Share Posted January 12, 2004 One word of caution on Bluestrat's advice on replacing electrolytic capacitors. Electrolytic capacitors are polarized with a positive and negative side. The negative side is usually designated with a "dash" or "-" along the side of the capacitor. Before you remove the old capacitor, note its polar orientation (make a picture to be sure you get the new cap installed in the correct polar orientation). I had to replace the pot on my Cry baby wah as these parts get worked a lot and do wear out. Mine started to get noisy but a worn pot causing intermittent contact could also give symptoms like those describe in your post. Link to comment Share on other sites More sharing options...
mound Posted January 12, 2004 Author Share Posted January 12, 2004 Thanks Bluestrat. I'll pull it apart and try replacing them as you suggested. I'll come back and let you know.. Anybody else have any suggestions? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 Ok. I see a single 4.7µF 50V electrylytic capacitor.. looking at the radio shack catalog online, the only close match I see is a 4.7µF 50V 20% Axial-Lead Non-Polarized version. It's got leads from each end rather than two from one end, but the non-polarized, I don't think that's match right? the only other caps are the "green square" kind (rectangles actually) two labeled 224K100V and two labeled 103K100v which I assume is the same as .22µF 100V and .10µF 100V respectivly? again on the radio shack catalog, the closest I see .22µF 50V and a 0.1µF 50V "PC-Mount Capacitor" (if you go to radioshack.com and past those into the search you get right to them.. won't post the URL 'cause it's very long) Thoughts? Do I need to go to Mouser or something and order these parts? also, might the inductor be worn out? or does the fact that the "wah" sound still works fine remove that possibility? thanks! -paul "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 14, 2004 Share Posted January 14, 2004 You can use non-polarized caps where polarized caps are; I've done it. Also, 50V caps should be fine in an effect pedal, where the power source is seldom more powerful than 12V to 18V. For that 4.7uF/50V you can sub a 4.7uF/35V radial that Radio Shack has. The 103K100v would be .01uF/100V. Radio Shack sells a .01uF 400V (orange) or a .01uF 50V (green). I'd take the original with me and try and match up the spacing of the leads so it will be a drop in fit. Either capacitor will work fine, but avoid using the .01uF/1000V ceramic disc caps for the best tone. If the pedal still wahs like it should, the inductor is fine. Also, if you replace the inductor, you're messing with the tone and value of the pedal. You might have one of those sweet Fasel inductors in there, and any replacement you could use would be a step down from the original. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 yeah, I would hesitate to replace the inductor. this pedal is "vintage" (though my buddy the owner has no intent of trying to sell it or anything..) I'll try out those caps, keeping the old ones in case there's a problem. Also - slightly different topic, my buddy was asking if some kind of gain circuit could be wired into this, aside from fixing the original signal loss, adding some kind of boost so that when he does kick it on, he not only gets the wah, but also gets some kind of amplification of the signal. Know of any DIY mod plans for something like that? I imagine if he wanted to go that far I'd probably suggest using a breadboard wired in after the switch so that we could experiment with different value components. Thanks! -Paul "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 oh also, you noticed I had incorrectly converted "103K100v" to 0.10µF and you stated it's actually 0.01µF... is the 224K100V actually 0.02µF rather than 0.22µF as I stated? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 14, 2004 Share Posted January 14, 2004 Originally posted by mound: oh also, you noticed I had incorrectly converted "103K100v" to 0.10µF and you stated it's actually 0.01µF... is the 224K100V actually 0.02µF rather than 0.22µF as I stated?103k100v - The 103k part tells us that the value is this: first digit = 1 second digit = 0 multiplier = 3 zeros value = 10,000pF 10,000pF = 10nF = .01uF 224k100v - this: first digit = 2 second digit = 2 multiplier = 4 zeros value = 220,000pF 220,000pF = 220nF = .22uF Pico (p) means value x 10^-12 Nano (n) means value x 10^-9 Micro (u) means value x 10^-6 Milli (m) means value x 10^-3 Kilo (k) means value x 10^3 Mega (M) means value x 10^6 Giga (G) means value x 10^9 Did that help, or did I just confuse you more? As far as adding gain, you could change the emitter resistor on Q1 (first transistor in the circuit) to a lower value. What type of pedal does your friend have? Here's a site with some great ideas for modifying wahs: Technology of the Wah BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
baronedo Posted January 14, 2004 Share Posted January 14, 2004 I suggest you try Small Bear Electronics instead of Radio Shack. Small Bear caters to stompbox builders and should have the correct replacement parts. Check out their website. They are very reliable and send things quickly via mail order and less expensive than Radio Shack. http://www.smallbearelec.com/ Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 yup, makes perfect sense.. I do have some more experience with electronics than my questions are leading you to believe I'm sure (hobbyist, no formal training) Things like converting labels to values I always have to consult a reference because I just don't know them off hand. Thanks though! (check out the wack pedalboard I built from scratch a few years back: http://www.liqwid.net/bassrig.php) (which I don't even use anymore having gone all rack) Anyway - I have a radioshack right downstairs from my office here, gonna do those mods tonight (just the caps) I'll let you know how it turns out! The pedal is a Dunlop Crybaby Wah.. I think he said it's like 20 years old or so. What value resistor do you suggest to increase the gain? ps. I checked out your homepage, you are truly a mad man! ;-) Lancer - thanks for the link! -paul "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Dennyf Posted January 14, 2004 Share Posted January 14, 2004 Here's a link to a great site all about the traditional two-transistor wah pedal, what each component does, and what changing each component will/can do. I added the input buffer, and Anderton pot-to-optoisolator conversion on my Dunlop Crybaby. But my Budda Bud-wah still sounds much better. band link: bluepearlband.com music, lessons, gig schedules at dennyf.com STURGEON'S LAW --98% of everything is bullshit. My Unitarian Jihad Name is: The Jackhammer of Love and Mercy. Get yours. Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 wow, great site.. should help me tweak away. thanks! "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 14, 2004 Share Posted January 14, 2004 Originally posted by mound: The pedal is a Dunlop Crybaby Wah.. I think he said it's like 20 years old or so. What value resistor do you suggest to increase the gain? ps. I checked out your homepage, you are truly a mad man! ;-) -paulMy Wah is a Dunlop Crybaby GCB-95, and on the first transistor I switched from a 390 ohm to a 220 ohm resistor. You could probably do the same on his Crybaby, as I believe that the circuits are the same except for the switching (the GCB-95 has an input buffer and isn't true bypass). I'm just a guitar gear freak! I love the cheesy old bargain stuff in particular. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 hey man it's all good! Anyway - I gotta figure out for sure which is Q1 and which is Q2 on this board before I go forward. I wonder if you could use like a 1P6T rotary switch and place a range of resistors in place to give selectable gain? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 oh I see.. we're talking about the resistor between the the Q1 emitter and ground right? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 14, 2004 Share Posted January 14, 2004 Originally posted by mound: hey man it's all good! Anyway - I gotta figure out for sure which is Q1 and which is Q2 on this board before I go forward. I wonder if you could use like a 1P6T rotary switch and place a range of resistors in place to give selectable gain?You probably could do that, but it might mess with the bias of the transistor. 220 ohms gives a nice boost, and a gritty wah tone, IMO. I wouldn't go any lower than 47 ohm if you go with the rotary switch, and that might cause the transistor to saturate. I haven't tried that, so I don't know. The mods I did to mine are changing the .01uF input cap to a .1uF, the 390 ohm Q1 emitter resistor changed to 220 ohm, and the 39k resistor in parallel with the inductor changed to 47k. To find Q1 you'll just have to trace from the input through the caps until you get to transistor. I'd trace out the whole circuit to a schematic unless I could find a schematic w/ layout. You might try to find the schematic and layout here: http://www.schematicheaven.com BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
Blue Strat Posted January 14, 2004 Share Posted January 14, 2004 Originally posted by mound: oh I see.. we're talking about the resistor between the the Q1 emitter and ground right?Yep, that's the one! BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
mound Posted January 14, 2004 Author Share Posted January 14, 2004 yah, I have the rest of the pedal in front of me now, easy enough to trace it out. I figure maybe use a rotary switch for 3 settings, the 470ohm existing, maybe 390 and 220.. what results do you find with the mods to the capacitor values? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 15, 2004 Share Posted January 15, 2004 Originally posted by mound: yah, I have the rest of the pedal in front of me now, easy enough to trace it out. I figure maybe use a rotary switch for 3 settings, the 470ohm existing, maybe 390 and 220.. what results do you find with the mods to the capacitor values?The bigger .1uF input cap helps with the ear piercing treble that the Crybabys do. It gives you a fatter tone, which I like. The 47k instead of the 39k narrows the sweep of the wah a little. The Geofex article recommends a 51k. I'm thinking hard about doing that Anderton scratchless wah mod on my pedal. I've got the stuff to do it here, and I can't seem to get the opamp autowah I was working on to function without squealing at me. I'm going to try that "Twin-T" wah also when I get the time. I personally wouldn't drill a hole in my wah casing; I've been there and done that, and I've got a big open 1/2" hole in the side of my wah. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
Dennyf Posted January 15, 2004 Share Posted January 15, 2004 While you're experimenting, you could do what I did and add some trim pots in place of, or in series with, some of the resistors you're thinking of changing. Easier than swapping out different values 'til you find what you like. Then you can either replace the trim pots, or leave 'em in case you change your mind. While I think I did increase the gain slightly thru mine, I think I went back to pretty close-to-stock values for components determining the "Q" and range of the wah. I have to look in my Bud-Wah to see how close it is to the Crybaby. Ya got me curious now! Re: the Anderton "scratchless" mod. Surprisingly, it hasn't hurt battery life much (and I thought it would), but I'm not sure I still have as much range as I did. Haven't explored any further mods yet, but youze guys are sparking my interest again. band link: bluepearlband.com music, lessons, gig schedules at dennyf.com STURGEON'S LAW --98% of everything is bullshit. My Unitarian Jihad Name is: The Jackhammer of Love and Mercy. Get yours. Link to comment Share on other sites More sharing options...
Blue Strat Posted January 15, 2004 Share Posted January 15, 2004 Originally posted by Dennyf: Re: the Anderton "scratchless" mod. Surprisingly, it hasn't hurt battery life much (and I thought it would), but I'm not sure I still have as much range as I did. Haven't explored any further mods yet, but youze guys are sparking my interest again. If you measure that LDR you'll find that they aren't 100k, they're closer to 50k at maximum resistance. That's why you're getting less range. Maybe you could connect two of them in series and use a brighter LED (yellow maybe?) to work them both? Did you use a current limiting resistor in series with the LED or just the pot and LED? BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
Dennyf Posted January 15, 2004 Share Posted January 15, 2004 Actually I still had a couple of the CLM6000s lying around, which have a max resistance of close to a meg, as I recall. I used one of those in the mod. They are, unfortunately, made from unobtainium. band link: bluepearlband.com music, lessons, gig schedules at dennyf.com STURGEON'S LAW --98% of everything is bullshit. My Unitarian Jihad Name is: The Jackhammer of Love and Mercy. Get yours. Link to comment Share on other sites More sharing options...
Blue Strat Posted January 15, 2004 Share Posted January 15, 2004 I've got a couple of the cadmium sulfide photocells that I've been using in projects, like my tremolo, and they measure 50k, and have a pretty good sweep to them. With a square wave low-frequency oscillator on the tremolo, it sounds a whole lot like a vintage Fender blackface amp's tremolo. It's even got the tick to go along with it! (I'm trying to fix that though... ) BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
mound Posted January 15, 2004 Author Share Posted January 15, 2004 wow.. a few replies overnight I see.. Couple of things, many of the mods you are talking about look similar to this: http://home.cfl.rr.com/dbhammond/crybaby_sch.gif Think that's a good starting point? I actually did decide to go with a small PCB mount trim-pot when I saw it at Radio Shack, then my buddy can tweak it as he likes later on. I had also looked at Anderton's "volume pedal descracher" circuit - is that the same thing for the wah? I'm not gonna worry about that though, my buddy reports no problems with scratchiness. Also as I recall it required 2 batteries didn't it? The Wah only takes one, how did you handle that? Drilling holes? He doesn't care, actually, that brings up something I forgot to mention, about a year ago we drilled a hole in it and put in an 1/8" jack wired to the +9V so he could get power from his power brick (I think it's a Dunlop Power Brick, something like that.) Then I thought, I wonder if this jack being in contact with the case could cause some kind of ground loop, since the case is connected to his other pedals, which each is powered as well by his Brick. He also drilled another hole to put both input and output jacks on the same side, so he's got a gaping hole in the case as it is. It also looks like you guys starting talking about some other things, using LED's etc.. I have no idea what you're talking about. Are you using them for their resistance? Anyway - didn't get a chance to pull out the soldering iron last night so no results to report. Finally- Bluestrat, I'm intriqued, do you have an EE degree? -Paul "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
mound Posted January 15, 2004 Author Share Posted January 15, 2004 oh and speaking of gaping holes, since there already is one, adding a knob that controls [insert wah aspect here] would probably be a "hey that's cool" thing for my buddy - assuming I'm using a trimpot for the Q1 emitter resistor, what might I try making variable with a 3 or 6 position switch for example? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Dennyf Posted January 15, 2004 Share Posted January 15, 2004 Originally posted by mound: I had also looked at Anderton's "volume pedal descracher" circuit - is that the same thing for the wah? I'm not gonna worry about that though, my buddy reports no problems with scratchiness. Also as I recall it required 2 batteries didn't it? The Wah only takes one, how did you handle that? -PaulActually, the mod I used is also on that "Technology of Wah Pedals" link I posted earlier. It does NOT require two batteries, you just tap off the existing battery. Bluestrat, I have the 2.2k resistor illustrated in the schemo. I guess I could try a smaller one for maybe a little more brightness in the LED section of the CLM6000, but I'm gonna try increasing the Q a little first. Actually, I think it works fine, it's just not as good as my Bud-Wah. band link: bluepearlband.com music, lessons, gig schedules at dennyf.com STURGEON'S LAW --98% of everything is bullshit. My Unitarian Jihad Name is: The Jackhammer of Love and Mercy. Get yours. Link to comment Share on other sites More sharing options...
mound Posted January 15, 2004 Author Share Posted January 15, 2004 looking at the "switched capacitors for Cf" mod on the technology of wahs page (http://www.geofex.com/Article_Folders/wahpedl/wahped.htm#opampvers) what would be 6 appropriate capacitor values? can I just basically pick any range of values from 0.01uF up to 0.1uF ? "You look hopefully for an idea and then you're humble when you find it and you wish your skills were better. To have even a half-baked touch of creativity is an honor." -- Ernie Stires, composer Link to comment Share on other sites More sharing options...
Blue Strat Posted January 15, 2004 Share Posted January 15, 2004 Originally posted by mound: It also looks like you guys starting talking about some other things, using LED's etc.. I have no idea what you're talking about. Are you using them for their resistance?I was talking about using an LED to provide light for a LDR (Light Dependant Resistor) for things like tremolo and wah. The LED controls the resistance that the circuit sees, so you could replace the 100k resistor in the wah with an LDR and then control the LED's brightness with the stock 100k pot. That's what de-scratches the wah; there's nothing mechanical to cause problems in the wah's circuit, and the LED isn't as sensitive as the audio circuit. Anyway - didn't get a chance to pull out the soldering iron last night so no results to report. Finally- Bluestrat, I'm intriqued, do you have an EE degree? -PaulYes, I've got an associates degree in electronics engineering technology. I'm going to school for my bachelor's degree now. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
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