SSIA - anyone have a schematic for the Colorsound inductorless (twin-t) wah? NOT the one at Fuzz Central with the inductor in it.
i asked a year ago and no one had it a few people sent me the one with the inductor in it but so far no luck. if you find it email me it.
Quote from: Ansili asked a year ago and no one had it a few people sent me the one with the inductor in it but so far no luck. if you find it email me it.
Yeah, I found your post when I did a search :) :) If I find it I'll post it up for everyone.
I built the one from GEO, uses opamp and no inductor...definitely Wahs and is quite 'adjustable'...circuit, box with treadle...only thing it doesn't yet have is a bypass switch...then I can really test it./
Quote from: petemooreI built the one from GEO, uses opamp and no inductor...definitely Wahs and is quite 'adjustable'...circuit, box with treadle...only thing it doesn't yet have is a bypass switch...then I can really test it./
Do you have the schematic or not?
I actually traced one a few months ago and it sounds great. I don't have the cap value of one tropical fish cap though. This board looked like a copy of the original though so I can't verify how accurate it is. I don't have a scanner so if I get a chance to take a picture of it I'll defiantely post it. Sounds great and is cheap to make.
Quote from: nirvanas silenceI actually traced one a few months ago and it sounds great. I don't have the cap value of one tropical fish cap though. This board looked like a copy of the original though so I can't verify how accurate it is. I don't have a scanner so if I get a chance to take a picture of it I'll defiantely post it. Sounds great and is cheap to make.
Great, someone who actually knows what they're talking about!! NS, I have a circuit drawing with no values below, if you can fill in the values that's good enough for me. Did you copy down the colors of the tropical fish cap? If so we can probably decipher the value from that. OK, check out the pic:
(http://img40.exs.cx/img40/2388/cs3.gif)
R1: 5M7 (!!!)
R2: 10K
R3: 330K
R4: 1M
R5: 180K
R6: 180K
R7: 470 ohm with a 100K pot in series
R9: 33K
R10: 100K
R11: 47K
C1: .01
C2: .015
C3: .0022
C4: .0068
C5: .1
C6: .01
C7: .0022
Schematic is probably 100% correct seeing how mine matches yours identically. C2 was the mystery cap but I must have taken it out and measured it... :). Please give credit if anyone decides to post future info about this pedal... :)
Thanks NS, this nut has finally been cracked!!! Strange that C3 and C4 are not matched (the same) though. I will redraw the schematic and post it for all later today.
Glad you could use it. I think I'm tossing a switch in my vox wah to change between circuits so I figured I should trace the circuit while I had a colorsound wah here.
Moot [?]...anyway the schem for the ductorless wah should still be up at GEO...
Looks like you're gonna use this discrete version...anyway RG does a good runthrough of what the circuit and components do...
Quote from: petemooreMoot [?]...anyway the schem for the ductorless wah should still be up at GEO...
Looks like you're gonna use this discrete version...anyway RG does a good runthrough of what the circuit and components do...
Duh. Your post was pointless because it didn't answer the question and provided no useful information in any way. The twin-t wah schem at GEO uses completely different circuit values. Anyway, here's the full redrawn schem:
(http://img9.exs.cx/img9/4021/cswah.gif)
interesting in the fact that it looks alot like the idiot wah......
Yup it's a simple Twin-T filter wah, the "trick" is the circuit values that give it the proper frequency range/response.
In a traditional wah, the Q varies as it sweeps (because, the R in series with the coil varies, I think). What this inductorless one does I can't imagine, anyone simulated it yet??
This one varies Q as well, by applying negative feedback around the notch frequency. RG's Tech of Wah explains it way better than I can:
http://geofex.com/Article_Folders/wahpedl/wahped.htm
Here's the sweep (simulated):
(http://img57.exs.cx/img57/1711/cssw.gif)
BTW the sim above is with a 2n5088 transistor (high gain). Lower gain transistors (like 2n3904) have a softer Q (less peaked sweep). If you're building this, I would suggest using the high gain transistor, then stick a trimpot on the emitter to adjust the Q (soft/sharp) as desired. Also, see the GEO article above on adding a 2nd transistor to buffer the output, it doesn't change the tone much (if at all) and it helps with other FX after.
The Twin T/Bridged T is a great circuit to implement as a wah. Simple and easy to control. Q does vary quite a bit with tuning. It's also a very easy design to play with. I personally think they make cool sounding VCFs, too, if you aren't too concerned with precise control over Q. Lots of design considerations. "Balance" of the RC components in the "T" networks, amount of gain, impedances of gain stage, gain capability of gain stage, allowable amount of distortion, and so on. And all can be explored with a single transistor design.
How did you implement it as a VCF, Tim? Just substitute a JFET for the pot, or is there more to it than that?
The twin T provides high Q only at the specific place where the components are matched per theory. The null gets less deep (that is Q goes down) as you move off the theoretical match. Changing the one resistor to move the frequency counts for that too, so the Q changes.
For another twin T wah, PAIA did one in a Poptronics article in the late 60's and also did a leslie simulator that way. I think it was the "Synthespin".
They're all quite similar. It's an inexpensive (compared to an inductor) way to get a bandpass filter.
Quote from: Ge_WhizHow did you implement it as a VCF, Tim? Just substitute a JFET for the pot, or is there more to it than that?
I was just being synthesizer-specific. Most typical synth VCFs offer steeper cuttoffs, more consistent Q across tuning range, and superior CV rejection. These are areas where the Twin T really can't compare with other VCF designs regardless of method used to tune the filter. Still, they're simple enough and sound good enough to be useful.
Does anyone have a practical layout done for this schem that they wouldn't mind posting?? I am not great with making them , even with a simple and small crkt like this but probably could do with a bit of time. Just thought It would be easier to see one that someone else uses to give me a 'template ' to go by or use.
thanks
I'm trying to breadboard this circuit using the most recent schematic from above, but I don't know where any connections are. Does the 5M7 connect to the C, B or both?
there's a pcb on paul marossy webpage.
i built it and works fine.
http://www.diyguitarist.com/PDF_Files/ColorsoundWahPCB.pdf (http://www.diyguitarist.com/PDF_Files/ColorsoundWahPCB.pdf)
as always, thank you paul marossy!
Hey Paul
I've tried to open the PCB for the colorsound wah a few different times in the last week...I get it to open but the page is blank and says its "done".
Is this just me?
Quote from: R.G. on September 21, 2004, 09:17:00 AM
For another twin T wah, PAIA did one in a Poptronics article in the late 60's and also did a leslie simulator that way. I think it was the "Synthespin".
I think Mark Hammer has the Synthespin article here:
http://ampage.org/cgi-bin/hammer/index.cgi?cmd=lt&xid=&fid=&ex=&pg=4
Quote from: Basicaudio on April 07, 2006, 01:23:19 AM
Hey Paul
I've tried to open the PCB for the colorsound wah a few different times in the last week...I get it to open but the page is blank and says its "done".
Is this just me?
It is probably your Acrobat reader version, update and you should be ok.
(that did it for me anyway)
CD, I'm surprised anyone is bothering to help you with the kind of reply's your posting, are you having a bad day?
Quote from: RedHouse on April 07, 2006, 10:09:50 AM
CD, I'm surprised anyone is bothering to help you with the kind of reply's your posting, are you having a bad day?
RedHouse, I'm surprised anyone is bothering to reply to a post almost two years after the fact. :icon_rolleyes:
Andrew
Quote from: The Tone God on April 07, 2006, 02:27:44 PM
Quote from: RedHouse on April 07, 2006, 10:09:50 AM
CD, I'm surprised anyone is bothering to help you with the kind of reply's your posting, are you having a bad day?
RedHouse, I'm surprised anyone is bothering to reply to a post almost two years after the fact. :icon_rolleyes:
Andrew
ROTFLMAO - there's a verified schematic, a layout, and a frequency response graph. I'll let the USEFUL information in this thread speak for itself. :) :) :)
I recently built this circuit on vero according to the layout at tagboard fx... http://tagboardeffects.blogspot.com/2012/03/colorsound-wah.html#comment-form (http://tagboardeffects.blogspot.com/2012/03/colorsound-wah.html#comment-form)
It was made according to the schematic at beavis audio... and it doesnt function correctly as it was. acted more like a tone control being turned up and down. I found this schematic and have tried to change my current vero board to match this schematic... I changed the two 100n caps on the left side of the board to 10n, and I changed the 33k resistor on the right side of teh board (the one in series with the sweep pot) to 470ohm like the schamtic from the previous page of this topic. And now it's getting a LOT closer.
However, the sweep is messed up. It doesnt do much in most of it, then it jumps and quickly shifts from bass to treble in the middle of the pedal sweep. I've tried adjusting the treadle. But I think it's either the pot of the circuit. I built it into a standard modern GCB95 crybaby, which I nkow has a 100k pot, but I dont know if its audio or linear taper. It kinda seems like its an audio taper and a linear taper might suit it a lot better. I know you can convert audio pots to linear but I'm not sure how... I've searched all over, but I'm not sure how change the taper without changing the actual value of the pot if anyone could point me in the right direction, that would be awesome!
Also, I'm not sure my vero currently matches up with the shcematic here. It has those changes right now, but I'm not sure i have the 100n caps and 10n caps right....
And... currently my sweep is backwards... toe up is treblely and toe down is more bassy. And although the pedal is working better than it was according to the beavis schematic and tagboard layout. I still dont think it gets bright enough at toe up position. As I said I've tried rearranging the treadle position on the pot. But thats not helping.
Any input or direction would be greatly appreciated, I'd love to help get these schematics right and give credit to the guys that pulled this schematic here together!
THANKS!
Thanks for this useful circuit!
(Just a question: can i transpose the twin-t part to a valvecaster circuit without changing any values of the components?)
here are some scans of an original board
(http://i26.photobucket.com/albums/c143/ringworm_1974/down077.jpg)
(http://i26.photobucket.com/albums/c143/ringworm_1974/down078.jpg)
gutshot
(http://i26.photobucket.com/albums/c143/ringworm_1974/PB0100181.jpg)
The pot was a 100k linear but that relies on having the colorsound type gear. A 100k log pot was used with a rack and pinion gear version of this circuit that was made by Frontline in the 80s, that should work with a crybaby rack and pinion setup.
In top image, the resistor on it's end in the top right is 33k
In top image, the resistor just hidden by the cap at bottom left is 100k
Transistor is C549C (i assume it's same as BC549C)
Markings on the polystyrene caps have faded, can just make out 2n2 on the one on the right. Second gut shot shows a 4n7 rather than 6n8.
Hope some of this helps.
i believe zak said a long time ago that the the wah probb was based on the colorsound inductorless. it has nice squishy, rainbow, or candy like sound.