Someone recently sent me an original Colorsound inductor wah pedal to tweak. When I was testing it out, I noticed that it had a really big range in sounds due to the 2" of travel it has!
So I was able to work out a deal with the owner of this wah pedal to do a partial trade for my labor - for an empty Colorsound wah pedal shell that he had. I initially put my Colorsound inductorless circuit in it, but it just didn't excite me at all. Today I decided to build this inductor based circuit and put it in there instead. It's very similar to a CryBaby, but without a resistor in parallel with the inductor, a 100K input resistor and a 100K resistor/10uF cap to ground at the inductor instead of 68K resistor/4.7uF cap.
Aside from a very microphonic inductor which I have to replace, I must say that this is the most expressive wah pedal I have ever played. I think I like it as much as the Maestro Boomerang. It's a different sounding wah, but I like it just as much. It's real good at the "whacka-whacka" thing, too.
One other thing I thought I'd mention is that I really like how the shell is designed. The mechanism that turns the pot is very ingenious and effective. It also feels a lot smoother than the rack and pinion system found in other wah pedals. In any case, just thought I'd share... :icon_cool:
Post a pic?
Years ago I had a friend who had such wah wah. One very clever former forumite send me pics of that mechanism years ago
I have thought that one thing that makes that mechanism work so good is it takes better advantage for full rotation angle of a potentiometer. I have very limited wah experience but those old cheap italians and japanese I saw did not make full travel. But with my friends Colorsound was such that you had to move your foot more, and that was not so nice feel action. I did some cardboard modellings and thought if you make the wah case and footrest longer perhaps you could get more "normal" feel to the colorsound mechanism. But I never managed to make some sawdust and diy plastic parts
And cant remember if it was workin opposite direction than my own wah
Quote from: Nasse on April 24, 2009, 12:05:32 AM
Years ago I had a friend who had such wah wah. One very clever former forumite send me pics of that mechanism years ago
I have thought that one thing that makes that mechanism work so good is it takes better advantage for full rotation angle of a potentiometer. I have very limited wah experience but those old cheap italians and japanese I saw did not make full travel. But with my friends Colorsound was such that you had to move your foot more, and that was not so nice feel action. I did some cardboard modellings and thought if you make the wah case and footrest longer perhaps you could get more "normal" feel to the colorsound mechanism. But I never managed to make some sawdust and diy plastic parts
And cant remember if it was workin opposite direction than my own wah
I think that is the key to it being so expressive - the more full pot rotation. The long throw does take some getting used to. I never liked the short throw on a CryBaby type wah - it's too short for my liking. I like the Maestro Boomerang in terms of length of throw, it has probably 1/2" more than the CryBaby does. And the Colorsound has even more than the Boomerang does. :icon_eek:
Quote from: RedHouse on April 23, 2009, 11:34:22 PM
Post a pic?
I'll try to take a few pics of it tomorrow sometime.
PS - Here is the schematic: http://fuzzcentral.ssguitar.com/schematics/colorsoundwah.gif
I used a 2N5089 for Q1 and a 2N3904 for Q2.
Here's a few pictures:
(http://www.diyguitarist.com/Images/CSW-1.jpg)
You can kind of see the rubber isolators on the four corners of the circuitboard here
(installed to help with microphonic inductor syndrome)
(http://www.diyguitarist.com/Images/CSW-2.jpg)
Look at the amount of travel this thing has... :icon_eek: It's cool, though, because
it can go from a more traditional wah sound to an almost synthy sound in the lower range.
(http://www.diyguitarist.com/Images/CSW-3.jpg)
I tried to get some close up pictures of the mechanism that operates the pot, but I couldn't get any good shots, so I made a little video of it: http://www.diyguitarist.com/Misc/CSW-Mechanism.MOV
I tried out a reissue coloursound a few years back. The pedal throw was enormous! It made me feel a bit seasick!
I must say, this thread and your clips of the Boomerang are starting to give me a hankerin' for building a wah. :icon_wink:
Quote from: DougH on April 24, 2009, 02:41:15 PM
I must say, this thread and your clips of the Boomerang are starting to give me a hankerin' for building a wah. :icon_wink:
Just do it! :icon_lol:
I'm going to do a soundclip for this Colorsound wah pedal sometime in the next day or two, because hearing is believing. :icon_wink:
It still only looks as though the pot is getting about 120 degrees of rotation in that video clip?
Quote from: R O Tiree on April 24, 2009, 04:42:39 PM
It still only looks as though the pot is getting about 120 degrees of rotation in that video clip?
I think it's more than that. It has a lot more range than a CryBaby does, so it's more than whatever the range is on a CryBaby.
I worked on one years ago. I traced the plastic cam and measured resistance at differet parts of the sweep (wiper to each end two reading for 1/2, 1/3 etc)
Now I can't find my tracing and readings. If you still have the real wha you might want to do this to figure out the taper. To do it 100% you would need to pull the pot and set it at different degrees and measure resistance to figure out the taper of the pot the total taper might be affected by the offset of the slot in the plastic piece that fits on the wha pot and the foot petal pin slides in.
i think there is something to the pot cam and foot petal and pot that makes the colorsounds inductor and inductorless whas sound good.
IIRC, a normal pot has a 270 degree rotation. So if something turns a pot thru 1/2 of its allowable rotation, that would be 135 degrees. Looking at the actual rotation of the pot shaft and not the plastic gizmo that turns it, I'm guessing that the Colorsound mechanism turns the pot more than 1/2 way thru its rotation, it's more like 180 actual degrees. That would make the throw more than 135 degrees, and more like 2/3 thru the allowable pot rotation. It's definitely way more than any other well known commercial wah pedal design I have seen.
Quote from: Paul Marossy on April 24, 2009, 06:39:04 PM
IIRC, a normal pot has a 270 degree rotation. So if something turns a pot thru 1/2 of its allowable rotation, that would be 135 degrees. Looking at the actual rotation of the pot shaft and not the plastic gizmo that turns it, I'm guessing that the Colorsound mechanism turns the pot more than 1/2 way thru its rotation, it's more like 180 actual degrees. That would make the throw more than 135 degrees, and more like 2/3 thru the allowable pot rotation. It's definitely way more than any other well known commercial wah pedal design I have seen.
Still looking like about 120 degrees and certainly not more than 1/2 travel on a 270 degree pot (although it could be 300)...
(http://homepages.tesco.net/~michael.jdcastle/pics/paul%20CSW%20mech.jpg)
I took screen shots of the cam at the extremes of travel (top 2 pics), marked a red line along the lower edge of the cam, rotated the left pic so the bottom edge of the shell lined up, then copied the area of interest and pasted it as a semi-transparent layer over the right hand pic, using the lug of the pot with the grey(?) wire as a common point of reference for the overlay. Voila! the pot travel is about 110 - 120 degrees, making some allowance for the change in camera angle. Check this, by looking at the very first and last frames in the video - the cam is about 30 - 40 degrees "above" the top face of the shell in the first frame. In the very last frame, it is about 80 degrees "below". Again, 110 - 120.
I'm with Gus on the geometry of the cam/actuator giving it this unusually vocal and expressive result.
No, it's more like 180 degrees, I can see the pot shaft turning approximately 180 degrees when the treadle goes from one extreme to the other. The cam is doing less work than the pot is. It's the amount that the pot is rotated that gives it this distinctive range in sounds - it's way more than the conventional wah pedal, and this is due to the design of the cam.
OK, I'm missing something here - you couldn't shoot it again looking at the pot from the other direction, could you?
Its very very nice looking, just gets hard to care about anything anymore.
Quote from: Pedal love on April 25, 2009, 01:24:17 AM
Its very very nice looking, just gets hard to care about anything anymore.
...which is one way of telling me to drop it, I suppose.
However, in the absence of a gear/pulley system with a better than 1:1 ratio, or another lever arm or 2, or some other system, there is no way that the pot shaft can be rotating further than the actuator arm (aka "plastic gizmo" in Paul's post above).
The older/wiser/more knowledgeable heads on this site are always encouraging people not just to be cooks (copying others' work) but learn to be chefs (paraphrasing a thread from some months ago). Some, like RG, Mark Hammer, etc, spend an inordinate amount of time explaining again and again, from different angles, for which I for one am most grateful. But, that does not absolve anyone from taking time and effort to prove things for yourself, learn the equations and how to manipulate them, researching other resources, so you
really understand why things happen the way they do, and not to just accept something just because someone else says so. And we all (should) know that, to make decent pedals, we have to be a combination of artist, elec engineer and mech engineer.
So, if Colorsound managed to design a way to get an extra 60+ degrees out of a simple 2-lever arrangement that only appears to rotate through 120 degrees or so, then I'd really like to know how they did it. If there's extra gearing in there of some description, then that explains all. If not... then it doesn't.
I don't know if this helps or not, but I've got an old FrontLine Wah which is basically a Colorsound Inductorless Wah. The shell and the plastic part look the same as Paul's.
That uses a 100k linear pot, mine measures as 91k, a full sweep of the pedal covers a range of about 41k, which is virtually half the rotation.
41/91*270 = 121.6 degrees. Thanks, slacker :)
Hmm... Am I missing something here? I have a CryBaby with the pinion gear mechanism, that rolls the pot over 240 degrees and actually travels through the whole range of the pot. The only thing I did was that I removed the bumpers from each end of the treadle. The reason the colorsound wah has a wider sweep has to be because of the circuit and not the mechanism, I think.
Something else to measure is the total distance of the rocker travel and then compare between different wha bodys.
Quote from: slacker on April 25, 2009, 08:15:16 AM
I don't know if this helps or not, but I've got an old FrontLine Wah which is basically a Colorsound Inductorless Wah. The shell and the plastic part look the same as Paul's.
That uses a 100k linear pot, mine measures as 91k, a full sweep of the pedal covers a range of about 41k, which is virtually half the rotation.
I was mistaken, it's not quite 180 degrees. I measured the angles between both extremes with a 360 degree protractor. It starts out at 0 degrees and stops at around 135 degrees, right before it actuates the switch.
Quote from: MohiZ on April 25, 2009, 09:33:10 AM
Hmm... Am I missing something here? I have a CryBaby with the pinion gear mechanism, that rolls the pot over 240 degrees and actually travels through the whole range of the pot. The only thing I did was that I removed the bumpers from each end of the treadle. The reason the colorsound wah has a wider sweep has to be because of the circuit and not the mechanism, I think.
I don't think it's because of the circuit. Comparing schematics, here are the only differences that I can see between the classic CryBaby circuit and the Colorsound circuit:
CryBaby Colorsound
Input resistor 68K 100K
Resistor to ground at inductor 82K 100K
Capacitor to ground at inductor 4.7uF 10uF
Resistor paralleling inductor 33K none
Q1 emitter resistor 470 ohm none
Q2 collector resistor 1K none
Both circuits use a 100K pot and a 500mH inductor, and everything else is pretty much the same otherwise. None of my CryBabys (I have several different versions, old and new) nor my Maestro Boomerang can match the sweep my Colorsound clone. The one very obvious difference between them is the distance that the treadle moves, which corresponds to how each wah sounds:
Crybaby, smallest sweep range, and least expressive
Maestro Boomerang, considerably more sweep range than a CryBaby has and is also more expressive
Colorsound, WAY more sweep range than the Maestro Boomerang and most expressive
I have been studying every wah circuit out there for a few years now, and I can only come to the conclusion that it has something to do with the design of the wah pedal shells and how much each one of them rotates the pot because all three of the aforementioned circuits are more or less the same when it comes to the core of the circuits.
If it is of interest, the Crybaby's maximum range with the rubber bumpers removed is about 4cm, measured as the distance between the tip of the rocker and the body. The rocker moves about 14 degrees from the toe position to heel position.
I don't want to argue with your experience, but I still think it's because of the circuit. Although it's basically the same, the slightly differing values of the components seem to make a large difference on the sweep range. I bought a Crybaby wah, and it had a very small and shallow sweep in stock condition. I've tweaked it for a few days now, and actually ended up with a sweep WAY too wide for my tastes, so I had to lessen it. The sweep now went from "wuuooaahh" instead of just "wah". In conclusion I noted that the gain of Q1 has an extreme effect on the RANGE of the sweep. Just try putting a 100k pot in place of its collector resistor. The downside of this is that it affects the wah's output volume drastically. I'm still trying to figure out a way around that.
Keep in mind, I haven't tried the colorsound wah.
EDIT: And, oh yea, the 2005 stock crybaby uses transistors that have a lot more gain than, say, 109b, that I've seen in some schematics. (I tried 109's in place of the stock trannies). I'd go as far as to say you're able to get a much wider sweep with these transistors than 109s. I can't tell what the new transistors are because it just says
"H MPS
418-
50 B"
on them, and I can't find any info on them.
Quote from: MohiZ on April 25, 2009, 10:30:36 AM
If it is of interest, the Crybaby's maximum range with the rubber bumpers removed is about 4cm, measured as the distance between the tip of the rocker and the body. The rocker moves about 14 degrees from the toe position to heel position.
I don't want to argue with your experience, but I still think it's because of the circuit. Although it's basically the same, the slightly differing values of the components seem to make a large difference on the sweep range. I bought a Crybaby wah, and it had a very small and shallow sweep in stock condition. I've tweaked it for a few days now, and actually ended up with a sweep WAY too wide for my tastes, so I had to lessen it. The sweep now went from "wuuooaahh" instead of just "wah". In conclusion I noted that the gain of Q1 has an extreme effect on the RANGE of the sweep. Just try putting a 100k pot in place of its collector resistor. The downside of this is that it affects the wah's output volume drastically. I'm still trying to figure out a way around that.
Keep in mind, I haven't tried the colorsound wah.
EDIT: And, oh yea, the 2005 stock crybaby uses transistors that have a lot more gain than, say, 109b, that I've seen in some schematics. (I tried 109's in place of the stock trannies). I'd go as far as to say you're able to get a much wider sweep with these transistors than 109s. I can't tell what the new transistors are because it just says
"H MPS
418-
50 B"
on them, and I can't find any info on them.
Hey, I'm not arguing, it's just debating. :icon_wink:
I was expecting someone to bring up the absence of a resistor on the emitter of Q1 and that being a "big factor". It does have an effect on the circuit because if there is not enough gain, it won't sound good. But it's not going to radically affect the sweep range of any wah circuit. It might alter the frequency response slightly, but it's not going to be anything big.
On the CryBaby sweep range, I'm talking about a stock pedal with all of the bumpers still in place. In fact, all of the wah pedals I am talking about here are 100% stock, no modifications to them in terms of removing rubber bumpers or anything. Maybe I need to try that on my CryBabys because none of them excite me at all in their current states. And I have several different versions from new to old, from obscure to very common and a couple of modded GCB-95 circuits, some with Fasels, some with the "dreaded" stock inductor in the current GCB-95s. I even did a Vox "Grey Wah" clone. Not a single one of them excite me at all - they are just not expressive enough compared to other wah pedals I have. Another very expressive wah clone that I built is the Parapedal. But that is a
completely different animal than any other wah pedal out there.
Anyhow, I will make a sound clip soon, you'll be able to hear that it has quite a sweep range.
Using the colorsound schematic I found at fuzzcentral
The first transistor has a grounded emitter two things this will affect compared to a crybaby. One the colorsound can have more gain(depends on where the the transistor is operating, closer to cutoff less or sat more) and the gain will be more nonlinear(more distortion) without the emitter resistor the crybaby has. Two the inductor does not has a damping resistor across it.
Something to try is to place the colorsound circuit in a crybaby or adjust a crybaby circuit to the colorsound
Q1 collector voltages and Q2 emitter voltages should help.
Quote from: Gus on April 25, 2009, 10:52:18 AM
Using the colorsound schematic I found at fuzzcentral
The first transistor has a grounded emitter two things this will affect compared to a crybaby. One the colorsound can have more gain(depends on where the the transistor is operating, closer to cutoff less or sat more) and the gain will be more nonlinear(more distortion) without the emitter resistor the crybaby has. Two the inductor does not has a damping resistor across it.
Something to try is to place the colorsound circuit in a crybaby or adjust a crybaby circuit to the colorsound
Q1 collector voltages and Q2 emitter voltages should help.
The resistor in parallel with the inductor adjusts the "Q". To quote something from GEO:
"Rq
This resistor is the primary determiner of the Q, or sharpness of the bandpass/resonance effect of the filter Values lower than 33K make the filter less sharp, reducing the quality of the wah effect. Values up to 100K contribute to sharper, peakier, more resonant tones. If it gets too sharp, the wah effect can be lost because it may not hit harmonics to emphasize." The absence of this resistor should make it a dull sounding wah then, but that is not what is happening in this wah because the "Q" sounds pretty high to my ears.
In the Colorsound circuit I built, using a battery that meaures 9.58V, Q1 collector voltage is 3.42V and Q2 collector voltage is 9.02 volts (small voltage drop thru the polarity protection diode I added). BTW, the transistors I used in my clone are similar in terms of Hfe, the gains are roughly equivalent to what it shown on the Colorsound schematic.
I have a Crybaby (Rev H board) and I just filmed a little vid of it doing its thing...
CryPaby Pot travel (http://homepages.tesco.net/~michael.jdcastle/vids/GCB95%20pot%20travel.MOV)
As you can see, I stuck a match-stick to the end of the pot.
About 135 degrees to the back bumper and quite a lot more if you compress it hard - about 170 degrees all told. The HotPotz II is a 315 degree pot so, for its "normal" range of travel, that's a 43% change in resistance (54% if you really rock hard back). Going with the numbers slacker provided above, that gives almost exactly the same - 45%.
All of which gives me a yen to pop a Colorsound board in there and see what happens :icon_smile:
MohiZ - They are MPS-A18, not MPS-418.
Datasheet here (http://www.fairchildsemi.com/ds/MP/MPSA18.pdf).
Quote from: R O Tiree on April 25, 2009, 11:05:39 AM
I have a Crybaby (Rev H board) and I just filmed a little vid of it doing its thing...
CryPaby Pot travel (http://homepages.tesco.net/~michael.jdcastle/vids/GCB95%20pot%20travel.MOV)
As you can see, I stuck a match-stick to the end of the pot.
About 135 degrees to the back bumper and quite a lot more if you compress it hard - about 170 degrees all told. The HotPotz II is a 315 degree pot so, for its "normal" range of travel, that's a 43% change in resistance (54% if you really rock hard back). Going with the numbers slacker provided above, that gives almost exactly the same - 45%.
All of which gives me a yen to pop a Colorsound board in there and see what happens :icon_smile:
Huh, I wonder why the two sound so much different then?
Quote from: R O Tiree on April 25, 2009, 11:11:21 AM
MohiZ - They are MPS-A18, not MPS-418.
Datasheet here (http://www.fairchildsemi.com/ds/MP/MPSA18.pdf).
That's correct. A 2N5089 and MPSA18 have similar Hfe numbers.
i have one of the red reissue colorsound wahs that came with the inductorless circuit. Last year I converted it to the old school inductor based circuit and i am quite pleased with it. It's a monster of a wah pedal in my opinion.
I find it ironic that you posted this just as i decided to build a boomerang.
Quote from: Exactopposite on April 25, 2009, 11:15:10 AM
i have one of the red reissue colorsound wahs that came with the inductorless circuit. Last year I converted it to the old school inductor based circuit and i am quite pleased with it. It's a monster of a wah pedal in my opinion.
I find it ironic that you posted this just as i decided to build a boomerang.
I still love my Boomerangs, and will continue to play them. They still are a fatter sounding wah pedal than any other wah circuit I have built, including the Colorsound wah. But the Colorsound wah's range exceeds anything I have seen to date.
Quote from: Paul Marossy on April 25, 2009, 11:17:38 AM
Quote from: Exactopposite on April 25, 2009, 11:15:10 AM
i have one of the red reissue colorsound wahs that came with the inductorless circuit. Last year I converted it to the old school inductor based circuit and i am quite pleased with it. It's a monster of a wah pedal in my opinion.
I find it ironic that you posted this just as i decided to build a boomerang.
I still love my Boomerangs, and will continue to play them. They still are a fatter sounding wah pedal than any other wah circuit I have built, including the Colorsound wah. But the Colorsound wah's range exceeds anything I have seen to date.
After i build the boomerang (in the next week or 2) we can compare notes.
nice nice, i've done the "Colorsound-mods" to my vox wah as well long time ago and i love it!!!! it's absolutely a LOT MORE VOCAL than a stack vox/crybaby!!!!!!
Quote from: Gila_Crisis on April 25, 2009, 12:06:58 PM
nice nice, i've done the "Colorsound-mods" to my vox wah as well long time ago and i love it!!!! it's absolutely a LOT MORE VOCAL than a stack vox/crybaby!!!!!!
Thanks for the interesting piece of info! I wonder just what it is that makes it so different then?
Two more things to add one is something I was told years ago. Adjust the pot in the holder for the sweep you want.
In the colorsound the pot is linear and if you rotate the body you can adjust it for more or less signal level to Q2 base. If you adjust it so the wiper is at the end of travel at full up or down will give two different max signal levels to Q2. One will have no series resistance after Q1 collector to "top" of pot and wiper(max level) one will have series resistance after Q1 collector to the wiper of the pot (less max level).
The next thing you can try is subbing in a say a 33k or 47K fixed resistor and a 100K trim pot(33k to 133k, 47K to 147K) for the 100K across the 10uf in the colorsound schematic. The node of the 470K, inductor, 10uf and 100K is at "AC ground" so that spot should have the least affect except for the DC bias of Q1 and the loading of Q1 collector stays the same.
3.42VD at Q1 collector is kind of low but it is more toward sat so more gain for smaller signals(I have posted many times 1/2 of the power supply might not be what you want the web crap set the collector of Q2 of a ff to 4.5VDC is not alway what you might want) Adjust the bias of Q1 collector up and down an note any changes in tone. I would try a little lower up to 5 stuff like 3.2, 3.75, 4., 4.25 etc. Could be 3.42VDC is what you want.
I would change one thing at a time and take notes
The distortion from Q1 could be a part of what you like, more distortion(harmonics) in the output of the wha
QuoteThe distortion from Q1 could be a part of what you like, more distortion(harmonics) in the output of the wha
Aha, I see what you are getting at. Maybe that is the case here. I assume that would be due to a lack of headroom?
Could I see that happening on an oscilloscope? And if so, what would I be looking for? I assume that I could feed it a 1v sine wave and look for clipping on the output of Q1? It doesn't sound distorted at all when you're playing a clean guitar thru it, though. I have a feeling that you wouldn't be able to see this without a spectrum analyzer, although I have a function generator that I could tweak the frequency on while looking at the waveforms...
Just used a calculator and I think it was 34 years or more ago I played trough that Colorsound, so no wonder if my knowledge is not so good.
I just did some rehearsal in geometry and my crude cardboard model gave 133 degrees of pot rotation
Just to tidy things up and get the 2 layouts people are linking to looking somewhat similar so it's easier to see what's going on, here...
Perfectly possible, then, by changing 2 resistors, 1 electro cap, removing one resistor completely and inserting jumpers in place of another 2 to convert any stock CryBaby into a Colorsound (without the geometry "advantage" that the Colorsound has by virtue of the levers vs the rack/pinion). Oops... EDIT and adding those 2 resistors at the output.
Sorry it's a bit big, but reducing it made it very jaggy...
(http://homepages.tesco.net/~michael.jdcastle/pics/CryBaby-Colorsound%20compare.gif)
Thanks! The schematic comparisons make it very easy to see the differences between the two circuits.
I have found that the Colorsound circuit in general has a drop in volume with the 100K/100K voltage divider on the output. So I replace the 100K series resistor with a 100K trimpot acting as a volume control, keeping the 100K resistor to ground:
|------ OUT
|
\|/
______/\/\/\/\______/\/\/\/\_____GND
100K 100K
TRIM
Give me a couple of minutes...
Here ya go...
(http://homepages.tesco.net/~michael.jdcastle/pics/CryBaby-Colorsound%20compare%201-1.gif)
R7 is the resistor to make a fixed resistor and pot for biasing in the colorsound. Also I don't think you will need to change the 47uf to 10uf C2 if converting a crybaby like wha it should not matter.
FWIW I do think a buffer before the wha circuit is a good idea, something like a high input resistance EF.
QuoteHey, I'm not arguing, it's just debating. icon_wink
I was expecting someone to bring up the absence of a resistor on the emitter of Q1 and that being a "big factor". It does have an effect on the circuit because if there is not enough gain, it won't sound good. But it's not going to radically affect the sweep range of any wah circuit. It might alter the frequency response slightly, but it's not going to be anything big.
No, I just didn't want YOU to think that I was arguing ;)
What I found out, having a 100k pot in place of the collector resistor of Q1, is that it affected the sweep range in a major way. The toe position frequency did not change, but the heel position frequency decreased with a higher collector resistance setting (expanding the sweep more into the bass range). A lower value collector resistor diminished the bass range of the sweep. By setting the collector resistor and the "sweep cap" just right, you could set the highest and lowest frequencies of the sweep pretty much anywhere you want. There might be some difference between changing the collector resistor and the emitter resistor. I didn't try changing the emitter resistor at all. They both affect gain, but the collector resistor doesn't change the amount of current flowing through the transistor, changing the emitter resistor does.
But, maybe this doesn't work so well if you have the stock bumpers in place and are only able to use part of the pot's rotation. Who knows? It's kind of tedious to try out every single possibility with these things.
About the Q resistor, since the Colorsound wah doesn't have it, it's the same as having a resistor with infinite resistance in its place. So it would have a very high Q, just as you thought it sounded.
Do I believe that a stock crybaby has a narrower range than a colorsound wah? Oh, undoubtedly. Do I think the range of a Crybaby can be modified to exceed the range of a Colorsound wah? Absolutely. Do I think it'll sound the same? No. Not unless you have a pot that's tapered _exactly_ right to match the mechanics of the Colorsound, which is highly unlikely. Guess I was just making a point that the amount of "expression" in a CryBaby can be extended. Talking about stock pedals, I'll shut up now. :)
Oh, and R O Tiree: thanks for pointing that out.
Quote from: Gus on April 25, 2009, 01:46:16 PM
R7 is the resistor to make a fixed resistor and pot for biasing in the colorsound. Also I don't think you will need to change the 47uf to 10uf C2 if converting a crybaby like wha it should not matter.
FWIW I do think a buffer before the wha circuit is a good idea, something like a high input resistance EF.
IIRC from RG's "Technology of Wah Pedals", C2 is made to look like a variable cap by virtue of the way it's connected (via various other components) to Q2 and the inductor. So I'd think it would be wise to go with the flow and make it 10µF, not 4µ7F.
Wouldn't be hard to adapt this concept to later CryBaby boards that have the input buffer already fitted.
QuoteIRC from RG's "Technology of Wah Pedals", C2 is made to look like a variable cap by virtue of the way it's connected (via various other components) to Q2 and the inductor. So I'd think it would be wise to go with the flow and make it 10µF, not 4µ7F.
It's C5 that RG means.
C5 is the cap made to look variable. C2 is to cause an "AC ground" at the node of R5, C2, L1, R7. Emitter of Q2 drives via C5 L1 and R2 and the base of Q1. Q2 is an emitter follower with a gain of just less than 1.
Paul if you have a scope and a triangle wave generator build a grounded emitter gain stage, try a 22k C to 9VDC a Si transistor a 10K base to ground and select or use a pot and fixed resistor base to +9 to bias it at different collector voltages, cap couple in and out use a signal gen set to triangle and watch the scope as you increase the drive to the circuit.
EDIT I see MohiZ posted about C5 when I was writing
Ahhh - light dawns :)
I went back and re-read it. The last cap RG mentions specifically in that para about "the secret" is the 4.7µ and then he just says "that capacitor" several times in the next few sentences... I remember reading it yonks ago and getting disconfabulated, thinking it was some kind of weird Thevenin thing that I couldn't get my head around. Makes much more sense now.
QuoteI went back and re-read it. The last cap RG mentions specifically in that para about "the secret" is the 4.7µ and then he just says "that capacitor" several times in the next few sentences... I remember reading it yonks ago and getting disconfabulated, thinking it was some kind of weird Thevenin thing that I couldn't get my head around. Makes much more sense now.
I know, I had to read it a few times over too after you mentioned the 4.7uF cap. :)
QuotePaul if you have a scope and a triangle wave generator build a grounded emitter gain stage, try a 22k C to 9VDC a Si transistor a 10K base to ground and select or use a pot and fixed resistor base to +9 to bias it at different collector voltages, cap couple in and out use a signal gen set to triangle and watch the scope as you increase the drive to the circuit.
Thanks, I will try that.
QuoteWhat I found out, having a 100k pot in place of the collector resistor of Q1, is that it affected the sweep range in a major way. The toe position frequency did not change, but the heel position frequency decreased with a higher collector resistance setting (expanding the sweep more into the bass range). A lower value collector resistor diminished the bass range of the sweep. By setting the collector resistor and the "sweep cap" just right, you could set the highest and lowest frequencies of the sweep pretty much anywhere you want. There might be some difference between changing the collector resistor and the emitter resistor. I didn't try changing the emitter resistor at all. They both affect gain, but the collector resistor doesn't change the amount of current flowing through the transistor, changing the emitter resistor does.
The Colorsound wah does go quite deep in the bass range. That's where it starts to sound synthy...
I don't know if this is helpful or not. I found this old file on my computer and uploaded it to my gallery folder. The thing I noticed is that some of it follows some of the things being discussed- input buffer, more gain in Q1, etc. This fattened up my crybaby pretty nice. Would be fun to try the Colorsound values.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=39651&g2_serialNumber=1)
Quote from: R O Tiree on April 25, 2009, 07:24:00 AM
Quote from: Pedal love on April 25, 2009, 01:24:17 AM
Its very very nice looking, just gets hard to care about anything anymore.
...which is one way of telling me to drop it, I suppose.
However, in the absence of a gear/pulley system with a better than 1:1 ratio, or another lever arm or 2, or some other system, there is no way that the pot shaft can be rotating further than the actuator arm (aka "plastic gizmo" in Paul's post above).
The older/wiser/more knowledgeable heads on this site are always encouraging people not just to be cooks (copying others' work) but learn to be chefs (paraphrasing a thread from some months ago). Some, like RG, Mark Hammer, etc, spend an inordinate amount of time explaining again and again, from different angles, for which I for one am most grateful. But, that does not absolve anyone from taking time and effort to prove things for yourself, learn the equations and how to manipulate them, researching other resources, so you really understand why things happen the way they do, and not to just accept something just because someone else says so. And we all (should) know that, to make decent pedals, we have to be a combination of artist, elec engineer and mech engineer.
So, if Colorsound managed to design a way to get an extra 60+ degrees out of a simple 2-lever arrangement that only appears to rotate through 120 degrees or so, then I'd really like to know how they did it. If there's extra gearing in there of some description, then that explains all. If not... then it doesn't.
Sorry Mike, I was just lamenting my own sad life. You didn't do anything. :icon_redface:
Ok guys I'll tell you what I did. I got tired of all these mechanisms and just got a 100k lin. fader. Same crybaby circuit, but I ripped the fader out of the housing so there was only the resist element and the phenolic base. I loosened the straight gear from the plastic holder/guide and glued the element along side of the straight gear, with the element facing the holder/guide. I imbedded and glued a piece of the wiper's metal, in the plastic holder/guide and put a wire through a small hole behind the wiper, connected all wires accordingly and presto. I 'm still working on it. A few major problems - 1) no metal surrounding it, not allowing a small faraday shield which helps pots with rf. 2)The wires need to be strong but light to move with the straight gear. 3)you still need an (n.c.) pot and round gear to give opposing physical resistance. The thing I'm trying to say is it does make a huge difference what you do mechanically. I'm going to try to work these things out and give you a demo on you tube. Its worth a shot. :icon_lol: :icon_lol: :icon_lol:
Quote from: Pedal love on April 25, 2009, 05:01:42 PM
Sorry Mike, I was just lamenting my own sad life. You didn't do anything. :icon_redface:
No worries :) Thanks.
Using a linear pot - keep us posted on progress? Sounds like it might have promise. Dust and fluff getting gummed up in the works might be a player, though?
While we are on the subject of pots, out of curiousity... does anyone know what the taper is on those Dunlop Hot Potz II pots? I know the pot taper also is a factor in how the sweep is on a wah pedal, besides the actual rotation of the pot.
Well, it turns out that the taper is seriously weird... I still had the base off mine from earlier, so I de-soldered the "Output" wire.
Looking at the cog and with the pot fully clockwise (which gives min resistance measuring from "Output" to the wiper):-
0 - 120 gives a steady reading of around 100 ohms.
120 - 135 increases to about 1k
135 - 180 rapid increase to 58k!
180 - 225 slightly less rapid increase to 91k
225 - 270 gentle increase to 97k
270 - 315 top reading of 99k (fully counter-clockwise)
So, given that the setup procedure is to put the treadle toe down, set the pot fully CCW, then lay the toothed bar up against the pinion, then rotate the pinion by one tooth CW and re-engage, then place the plastic spring up against the bar and tighten the screw... and there are 14 teeth on the pinion... that's retarded by about 25 degrees which gives 98k with the treadle fully toe down and the pot at 290 degrees.
For the next 20 degrees, we only get a 1k drop...
For the next 45 degrees, we drop 6k
For the next 45 degrees, we drop 33k
That's 110 degrees, so far, and another 25 degrees will take us down to about 30k.
That's a total of a 70k drop over the 135 degrees of "normal" travel I showed in my video earlier but it is not, as I've shown, linear over the range. Instead, it's quite rapid from fully heel down to about 80% of travel, then it slows right down over the last bit.
Remember from your video, Paul, where the first bit of travel of the treadle the cam turns quite rapidly, then it slows right down at the end? Well...
...this weird taper wouldn't be ANYTHING to do with trying to emulate the rotational behaviour of the cam in your Colorsound, would it? A small tweak would give us an almost identical R vs relative treadle-throw curve as the Coloursound, and would result in a resistance change in the order of 40k or so, again, just like the Coloursound. OK, the snag is that the treadle on a CryBaby shell doesn't have to travel as far to get the same change as the Coloursound does, which makes it more of a blunt-edged sword and harder to play subtly, but it's k-i-i-i-i-i-nd of trying to do it.
Every day's a learning day, isn't it? :)
Update - I just tweaked the pot angle as I reassembled it, and got it going from 99k down to 45k. That's probably as close as I can get it without breaking the pot as the switch is engaged (that's why they advise to knock it back from fully CCW by one tooth of the pinion, I assume). Following the procedure exactly gave a minimum of 28k.
So, if you do the Coloursound mods on a standard CryBaby, you can expect it to be even more bassy and synthy down the bottom end, I guess, extrapolating from Paul's descriptions right at the beginning of this saga.
Here's the curve:
(http://homepages.tesco.net/~michael.jdcastle/pics/Hot%20Potz%20II%20Taper.jpg)
Huh, except for that really flat spot at the beginning, the Hot Potz II pot taper looks pretty linear right up to the end. Thanks for doing that! After all of this input from everyone, I think some of the difference must be to do with the linear pot taper vs. the taper on those CryBaby pots.
Just for fun, I drew up the Colorsound wah shell in AutoCAD just to show how that cam works. It's not 100% accurate, but I did take the actual measurements and stuff to make the drawing, so it should be pretty close to the real thing (let's say 95% accurate) - http://www.diyguitarist.com/PDF_Files/ColorsoundWahShell.pdf
This was a very interesting discussion, and I think we got to the bottom of what is going on in this wah pedal of mine. I guess I jumped to conclusions a bit too quick...
This has evolved into quite the wah thread. Thanks for the info, guys.
Nice autocad drawing of the Colorsound, too Paul. Very nice as a matter of fact. :icon_cool:
Thanks for the graph and the AutoCAD drawing folks! I guess the Hot Potz is trying to be an "S" taper pot, which I've heard is sometimes used in wahs.
Quote...this weird taper wouldn't be ANYTHING to do with trying to emulate the rotational behaviour of the cam in your Colorsound, would it? A small tweak would give us an almost identical R vs relative treadle-throw curve as the Coloursound, and would result in a resistance change in the order of 40k or so, again, just like the Coloursound.
That's what I'm talking about! Since the Crybaby's pot turns in a linear fashion with the treadle movement, the taper is used to compensate. The Colorsound mechanism naturally emphasizes the bottom and high end of the sweep, because the pot turns slower in those positions.
The Colorsound mechanism looks similar to the one found on my Bespeco cheap-o wah, except that that one really doesn't work too well. It used special pots that only had 90 degrees of rotation available.
Quote from: MohiZ on April 26, 2009, 05:34:32 AM
Thanks for the graph and the AutoCAD drawing folks! I guess the Hot Potz is trying to be an "S" taper pot, which I've heard is sometimes used in wahs.
Quote...this weird taper wouldn't be ANYTHING to do with trying to emulate the rotational behaviour of the cam in your Colorsound, would it? A small tweak would give us an almost identical R vs relative treadle-throw curve as the Coloursound, and would result in a resistance change in the order of 40k or so, again, just like the Coloursound.
That's what I'm talking about! Since the Crybaby's pot turns in a linear fashion with the treadle movement, the taper is used to compensate. The Colorsound mechanism naturally emphasizes the bottom and high end of the sweep, because the pot turns slower in those positions.
The Colorsound mechanism looks similar to the one found on my Bespeco cheap-o wah, except that that one really doesn't work too well. It used special pots that only had 90 degrees of rotation available.
It's funny you should mention S-taper, MohiZ...
I took Paul's AutoCad drawing (nice one, BTW :) ) and then pulled it apart in PaintShop Pro, ending up with images of the shell, the treadle and the cam and then set about laying the cam and treadle at various angles to construct the relationship.
The first big surprise is that the treadle only moves 16.5 degrees!!! It looks as though it should be a lot more, but that's the rotation angle I ended up using to get from heel down to toe down on Paul's AutoCad pic.
(http://homepages.tesco.net/~michael.jdcastle/pics/CS%20Treadle%20vs%20Cam.jpg)
Having got these numbers, I popped into Excel and then scaled the cam angle (which turned out to be 123 degrees travel... 8) ) into Resistance, based upon the info provided by slacker about 2 pages ago - linear pot, max 91k, 41k change across the whole range:
(http://homepages.tesco.net/~michael.jdcastle/pics/CS%20Treadle%20vs%20R.jpg)
OK, it is a lot smoother than the CryBaby graph, and doesn't tail off as sharply as I though it would. Mind you, the extra throw on the treadle compared with the Crybaby provides for finer control.
The end result is that we now have a
direct comparison between treadle position and R for both pedals. I'd say we all know a hell of a lot more about wahs today than yesterday. Possibly more than we ever wanted to ;D
QuoteOK, it is a lot smoother than the CryBaby graph, and doesn't tail off as sharply as I though it would. Mind you, the extra throw on the treadle compared with the Crybaby provides for finer control.
As a nerdy sidenote, it's actually one half of a sinewave (well pretty close anyway), because of the way the mechanism turns the pot. And 16,5 degrees is quite a lot more than a Crybaby - even with the bumpers removed, allowing for a lot wider throw, the crybaby's rocker only moves about 14 degrees from heel to toe! You might think two and a half degrees wouldn't make much of a difference, but that's noticeable compared to 14 degrees. A stock crybaby might have, maybe, 10 degrees of treadle throw.
Wow, you guys have been busy since I was here last! :icon_eek: I like how you guys have really dived into this topic, and I think we all learned a lot in this discussion. I don't know why, but I have become really fascinated with wah circuits in particular, they are just very interesting. :icon_mrgreen:
Just keep in mind that my AutoCAD drawing might be off a little bit in function compared to real life. I think the pot rotates about 130 degrees, but it might be closer to 125 degrees or something a little bit beyond that. It's definitely at least 130 degrees when it actuates the bypass switch.
I uploaded a quickie soundclip I made this morning using my SpankenStrat (http://www.diyguitarist.com/Guitars/SuperStrat.htm) thru the Colorsound wah into my Zoom 9030 effects unit with my own started from scratch customized preset. I am using primarily the mid & neck pickups (Fender "Hot Noiseless" pickups designed for Jeff Beck), but I switch the pickups here & there and some of it it also using the DiMarzio FRED humbucker on the bridge. It starts out in bypass mode and then goes into wah mode and stays there. I tried to do some different styles of music on different places on the neck to take it for a good test drive for y'all. I'm still learning how to use the thing as a small amount of movement on the treadle can really change the sound very quickly!
Anyhow, here it is: http://www.diyguitarist.com/Sounds/ColorsoundWah.mp3
The treadle sweep of stock crybabies is pretty small. Not sure why they put such thick bumpers in em. Shaving em down so theres just enough to keep it from metal to metal at each end adds quite a bit of travel. Ive also put a momentary switch in the treadle of mine as the bypass switch and eliminated the regular one under the toe end this adds some to the travel as you can push it down to almost metal to metal without turning it on or off. Plus all I have to do is step on it for it to work and take my foot off to turn it off. Course you cant leave it in a position as a filter and go somewhere else while playing. But this thread has been very informative. I have 3 empty housings to mess with. Im gonna have a stock 1 and have 2 more for various mods. Much easier to hear the difference on the fly. Waiting on my order form mouser to get here. Got 5 of the eleca inductors from smallbear to mess with in my modded pedals. Also a stock dunlop wah pot, a hot potz and a ICAR to see which I like the best.
The Colorsounds give you more control of the sweep with that wide treadle range, but I agree with the "it's in the circuit" camp. I have a rare 800mH inductor Colorsound and a RMC Wheels Of Fire and the RMC pretty much nails it tonally even with the narrower physical sweep.
Paul that thing is like Whaaa! I think you are on to something keep the wah output but get the feel for the control more- but that really reaches out and grabs you by the neck! Very cool.
Quote from: Pedal love on April 26, 2009, 08:36:19 PM
Paul that thing is like Whaaa! I think you are on to something keep the wah output but get the feel for the control more- but that really reaches out and grabs you by the neck! Very cool.
Yeah, it's kind of cool, huh? I like how it gets real synthy sounding about 60 seconds into the soundclip, it's an interesting effect.
If I play it for a while, I can use it pretty well. It's a bit hard to get it to sound just right when I first sit down to play it, though. I guess it's just a matter of getting used to it like I have done with all the other ones I play more than occassionally.
Once again, this is an excellent thread. It's got me thinking... I have a wah I'm building right now using a CB shell, and I'm going to modify the treadle to give it a longer throw:
(http://i337.photobucket.com/albums/n370/jusepics/wahthrow.jpg)
Maybe it will get me in the Colorsound ballpark :icon_wink:
Quote from: juse on April 26, 2009, 10:22:18 PM
Once again, this is an excellent thread. It's got me thinking... I have a wah I'm building right now using a CB shell, and I'm going to modify the treadle to give it a longer throw:
(http://i337.photobucket.com/albums/n370/jusepics/wahthrow.jpg)
Maybe it will get me in the Colorsound ballpark :icon_wink:
Hey, before you do that, make sure that it won't exceed the travel allowed by your gear. I think the rack might go past the gear and come out when in heel down position...
Yeah, I thought of that. I'll have to make a new rack gear for it to get the full travel. I was also going to put an adjustable bolt/nut/nut bumper setup to finetune the throw.
Quote from: juse on April 26, 2009, 11:26:51 PM
Yeah, I thought of that. I'll have to make a new rack gear for it to get the full travel. I was also going to put an adjustable bolt/nut/nut bumper setup to finetune the throw.
Sounds like you have it all under control...
The other thing to bear in mind is, go have a look at that graph I posted a page or so ago about Resistance vs Pot Angle fot a Hot Potz II pot. There's a huge region in the heel down region where it goes to about 100 ohms and doesn't change at all. Pointless, perhaps, to shave a huge chunk off the back of the treadle only to find that, by the time your foot gets that far back, it's not actually doing anything anyway.
He could always use some other pot than the Hot Potz... But anyway, all you need to do on a crybaby is take off the rubber bumpers and the mechanism'll turn the pot 270 degrees. That's the full range of your average pot. No need to shave off material.. unless, of course, you're going to modify the mechanism as juse evidently is going to do..
Thanks, Mohiz - that has sparked off another train of thought...
So, taking the bumper off will give 270 degrees of rotation. The Hot Potz II has a total of 315 degrees. Take off 25 degrees or so (from the setup procedure, which stops you breaking the CCW end-stop of the pot when you depress the toe switch) and that leaves only 20 degrees remaining at the heel end. Anyone want to bet that Dunlop took account of this when designing the spec for the Hot Potz? "Ooh, I wonder if people will take the back bumper out to get more travel?"... "Probably - we'd better give them another 20 degree buffer, then."
The most common commercially available pots are probably those with 300 degree travel. Some are only 270 (Colorsound pot anyone?). Let's compare the rotational stop strength of a typical Alpha pot, for example, at around 5kgfcm, with what you can apply with your foot... That's a 5kg weight on a 1cm lever arm, or a 1kg weight on a 5cm lever arm. It's about 5cm from the axle to the back of the treadle, and the rack is about 10 cm forward of the axle, which is a 1:2 mech adv, so we could put a >2kg weight on the back of the treadle and the end-stop would break. How much torque do you think your foot can apply to that end-stop?
The more I think about this, the more convinced I am that the gearing and geometry of the Crybaby shell was done for very good reasons. And it's built like a tank to deter the casual optimist with a Dremel from hacking it about and breaking stuff.
That's probably true. I was talking about taking both the front and the back bumpers away. The 270 degrees was an estimate (about 2/3 of a full circle is what it looks like), though it's probably not too far off. Anyway that's the range of the pot that's currently inside my Crybaby (I checked - in the extreme positions the mechanism is resting against the pot's end-stops - can you imagine the range is JUST right for it ;D). It's not a stock pot so I can't say if the one originally in there had a different range.
Just a suggestion for those thinking of modifying their CryBaby shell to make it more like a Colorsound wah in terms of function:
If you want to avoid any hassles with the weird taper on the Hot Potz II, just use a regular Alpha 100K linear pot instead. Sure, it won't last as long, but a replacement is only $3 at RadioShack and we all know how to solder here... so replacing it after it wears out is relatively easy. :icon_wink:
Quote from: R O Tiree on April 27, 2009, 03:00:29 PM
Thanks, Mohiz - that has sparked off another train of thought...
So, taking the bumper off will give 270 degrees of rotation. The Hot Potz II has a total of 315 degrees. Take off 25 degrees or so (from the setup procedure, which stops you breaking the CCW end-stop of the pot when you depress the toe switch) and that leaves only 20 degrees remaining at the heel end. Anyone want to bet that Dunlop took account of this when designing the spec for the Hot Potz? "Ooh, I wonder if people will take the back bumper out to get more travel?"... "Probably - we'd better give them another 20 degree buffer, then."
The most common commercially available pots are probably those with 300 degree travel. Some are only 270 (Colorsound pot anyone?). Let's compare the rotational stop strength of a typical Alpha pot, for example, at around 5kgfcm, with what you can apply with your foot... That's a 5kg weight on a 1cm lever arm, or a 1kg weight on a 5cm lever arm. It's about 5cm from the axle to the back of the treadle, and the rack is about 10 cm forward of the axle, which is a 1:2 mech adv, so we could put a >2kg weight on the back of the treadle and the end-stop would break. How much torque do you think your foot can apply to that end-stop?
The more I think about this, the more convinced I am that the gearing and geometry of the Crybaby shell was done for very good reasons. And it's built like a tank to deter the casual optimist with a Dremel from hacking it about and breaking stuff.
What about these pots? These are what I'll be using. Any specs on them?
(http://i337.photobucket.com/albums/n370/jusepics/HotPotz-1_cu.jpg)
(http://i337.photobucket.com/albums/n370/jusepics/HotPotz-1.jpg)
I was going to put an adjustable stop to fine tune the throw after I chopped it. Are you saying that I'm wasting my time?
QuoteWhat about these pots? These are what I'll be using. Any specs on them?
I assume that they are they the same thing as the Hot Potz IIs, taperwise.
Right you are, R O Tiree & Paul ..... on a HotPotz-II there is 315° of travel, and I measured the same for a HotPotz-1. I measured the degree of travel with the stock rack gear and after full extension there are 3 teeth's worth of travel left in the pot rotation, or about 45°.
(http://i337.photobucket.com/albums/n370/jusepics/45deg.jpg)
At first I thought this was a major amount of wasted potential, I mean, that's 1/8 of the total amount. But, like you said, after factoring in the buffer needed to keep from snapping the post off of the pot in either direction, that leaves me about 1 extra tooth's worth of travel to somehow magically make this a fire-breathing deep-chested monster. But, I'm thinking the CB is about right the way it is as well. Good call. I'll put up my chop saw......... (I will be leaving the bumpers off, though ;D )
The sweep range might be easier to control, though, if you had a longer throw on the treadle. Even with the bumpers off the Colorsound seems to have a lot longer throw than the Crybaby. The Crybaby circuit can be modified to give a wider sweep, or you could just stick a Colorsound circuit inside. As of now I think, because the range is shallower on the Crybaby, they've also made the treadle move less to make it easier on your foot.
I think that the Colorsound inductor wah also makes for a nice "Q-filter" sound. I am playing it mostly that way on the first tune called "The Journey" on the player here: http://improvisingguitarists.ning.com/profile/PaulMarossy
I think it will sound real nice when I get the keys and real drums added to it.
EDIT: Also, I think the suggestion that the distortion from Q1 being part of why I like this particular wah might have some validity. I haven't looked at it with a scope yet (argh! only so much time in a day), but with a clean guitar sound, I can hear that it is kind of mildly boosting the signal with I think a slight bit of distortion.