Colorsound - Wah+Fuzz+Swell  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Bernardduur
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Post by Bernardduur »

GeekMacDaddy wrote:This might help;
Awesome!

Double pot wah? Sweet!
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Manfred
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Post by Manfred »

A friend of mine bought this pedal a few years ago, but it does not work an he gave it to me for repair.
The extra potentiometer on the side works was added later by the previous owner, I removed it in the meantime to restore the original wiring.
I made a PCB clone for tracing and drew a schematic. I measured the values of the coil with L = 482mH and Rdc = 28.1 Ohm.
What surprises me is that the capacitor to the coil is 10uF instead of the usual 5uF.
Also the smoothing capacitor has a value of 50uF instead of the usual 25uF, also the emitter bypass capacitor has a value of 10uF instead of 4.7uF.
The Pedal ist dated Decemeber 7th, 1973.
Does anyone have this pedal and can compare the values?
COLOR SOUND WAH FUZZ SWELL December 1973 shot1.jpg
COLOR SOUND WAH FUZZ SWELL December 1973 shot2.jpg
COLOR SOUND WAH FUZZ SWELL December 1973 shot3.jpg
COLOR SOUND WAH FUZZ SWELL December 1973 shot4.jpg
COLOR SOUND WAH FUZZ SWELL December 1973 shot5.jpg
colorsound_wah-fuzz-swell 1973 Layout Top.JPG
Colorsound_wah-fuzz-swell 1973 Layout Bottom.JPG
COLOR SOUND WAH FUZZ SWELL Schematic December 1973.jpg
Colorsound Wah-Fuzz-Swell Service Schematics.jpg
SprintLayout 6.0 file with component designators is in progress.
Last edited by Manfred on 15 Nov 2022, 02:03, edited 2 times in total.

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george giblet
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Post by george giblet »

Does anyone have this pedal and can compare the values?
About 2 years ago I compiled some info on those Colorsound Wahs (and all the variations).
It was a bit of a headache and overall only a small number of samples for each model
could be found.

That Dec 1973 board looks very similar indeed to an Oct 1973 board I saw:
- 1973 Wah-Fuzz-Swell units used a single PCB.
- Clear block poly caps. Used on many Colorsound board around 1973/74
- Siemens BC169B transistors. Tinned lead which protude through the top of the device
- Siemens P14x8 potcore, T26 material. Again common for the era.
- Large body resistors, exactly like yours.

As for the electrolytic caps, the October 1973 unit had
- 2x10uF 16V, Sprague
- For the 47uF I don't have a confirmed value. However the package for your 47uF/10V
is very large. Larger than the 10uFs and in fact larger than the inductor. On the October 1973
unit that cap was 70% smaller than the 10uF's and nowhere near the size of the inductor.
For that reason I suspect it was in fact 25uF (Siemens).

Here's one with 22uF,
https://reverb.com/item/17335679-colors ... swell-1973

As for the inductor:
- Joe Gagan measured a 1972 Black Wah-Wah at 520mH 27 ohm. Which very much agrees with your 480mH 28 ohm.
500mH +/- 20mH is well within the expected +/-20% to 30% for these cores. The temperature coefficient is
probably 0.5%/degC to 1%/degC.
- The core is a Siemens P14x8 potcore, gapless with a center-hole, T26 material.
The T26 material ui is about 2200 and the AL is around 2100 nH/t^2.
I'm pretty sure the wire used was 38AWG (based on the resistance).

FWIW the 1972 Wah-Fuzz-Swell uses two PCBs - that's the 1971 factory schematic you posted.
The poly caps on the Wah board were Philips tropical fish and poly caps on the Fuzz board were
the turquoise Erie caps.

Something I noticed about the parts on Colorsound boards is they follow both the year and the model.
You might see different caps on different model boards made in the same year. No doubt the boards
were made in batches and used in multiple products. Later models don't necessarily use the same
schematic as earlier units. I saw quite a few minor variations. The tell tail signs of different era's is the
differ style of parts used. For example late 70s units had green caps and smaller body 1/4 watt resistors.

FWIW, the inductor should be 500mH on the schematic.

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Manfred
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Post by Manfred »

Thank you Georg for your great and detailed reply, I really appreciate it. :worship:
FWIW, the inductor should be 500mH on the schematic.
Thanks also for the hint, I edited the post above and swapped out the schematic for the one with the correct value of the coil.

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Manfred
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Post by Manfred »

Now the PCB layout is finished, the components have the same identifiers as in the schematic.
There is a solder lug mounted on the component side, this is used to make the ground connection from the board to the case via the mounting screw.
colorsound_wah-fuzz-swell-ComponentsSide.jpg
COLOR SOUND WAH FUZZ SWELL Schematic December 1973.jpg
colorsound_wah-fuzz-swell 1973 Layout Top.JPG
Ready-to-print PDF-files: Sprintlayout6.0-file:
colorsound_wah-fuzz-swell-layout.zip
(25.57 KiB) Downloaded 15 times

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Manfred
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Post by Manfred »

The pedal works again.
C7 and C3 were defective, C2 and C8 had a too high ESR value.
For C7 an NOS electrolyte with the original value of 25uF was installed.
I read some voltage values and entered those into the schematic.
COLOR SOUND WAH FUZZ SWELL Schematic December 1973 voltages.jpg

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Manfred
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Post by Manfred »

The pedal is now repaired and working again.
For clarification of the switch functions I made a table.
COLOR SOUND WAH FUZZ SWELL December 1973 fixed.jpg
COLOR SOUND WAH FUZZ SWELL December Function Chart.jpg
COLOR SOUND WAH FUZZ SWELL December Function Chart.jpg (46.58 KiB) Viewed 114 times

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