This project has turned into an interesting exploration of the Wah-Wah and it's origins. While I was looking for a replacement inductor, I ran into many interesting articles and I eventually found the patent for the wah-wah. I was able to find a schematic of a Colorsound Wah+Fuzz+Swell that was produced by Colorsound in 1971. The schematic shows two PCBS---Close enough.
The following three articles all cover the various aspects of the wah all the way from an artists point of view deep down to the nitty gritty technology.
There is even a movie, Cry Baby: The Pedal That Rocks The World, that is both entertaining and well produced and features some heavy hitters in the music biz.
It looks like most of the wah pedals, past and present, are not only based on the original from Bradley J. Plunkett of Thomas Organ but are actually exact or near copies.
The inductor has changed in the wah pedal through the different models and years. The first wah-wahs were made in Italy for vox and distributed under the "Cry Baby" brand for sale in the united states by Thomas organ. According to the accounts in the articles listed above, the "Halo" was the first inductor used.
This article in DIY stomp boxes forum Wah Inductors and magnetism shows a wide variety of inductors. The forum posting exemplifies the obsession and passion some folks have for the elusive tone.
|Halo||This is the first style to appear in a wah-wah pedal. There are several manufacturers making this inductor today including Dunlop. The Whipple Halo is shown.|
|Film Can||Not much written or talked about with this inductor. Seems to have only been used for a short time in the early production models. Presumably, the can is to shield the inductor from RF.|
|Fasel||There are two version of this one. A yellow pot core(shown) and the red toroidal. Dunlop makes both. People love to comapare the two. This inductor was Italian made and used by Jen manufacturing in the early days.|
|TDK 5103||This was used after Thomas organ moved Cry Baby production to the united states. This doesn't seem to be a favorite.|
|Stack of Dimes||This version is used in many early clones including Greg's Colorsound. This is a pot core ferrite. Very easy to make and components are readily available today.|
The shot below shows a great selection of inductors from the article on DiyStomp boxes. The author measured two key elements, The inductance and DC resistance. He did this experiment looking for the source of the mojo in the inductor. Hats off! Thanks for all the work.
Most of these devices look like pot core inductors in the stack of dimes style. There are three in the middle of the photo that look different and interesting.
Ok, we had a nice exploration through the inductor wonderland and we learned the history of the wah and its inventors. We also learned this effect was immediately cloned all over the world. The most favorite clones are the Colorsound wah (English) and the Foxxtone (USA).
So what is the big surprise, you ask? While I was doing all the research for Greg's pedal, my gear acquisition syndrome (GAS) kicked in and I found this pedal on ebay. It is not working but most of the components are there. I got it really cheap. Restored, this pedal can sell for $500. I got it for $85 plus shipping. I got it home and found that the inductor is missing (good thing I did all this research) and the POTs are in rough shape. Shouldn't be too hard to get it working. But, that is a story for another blog series.
Next time, disappointing news on the original stack of dimes inductor in Greg's colorsound and what we are going to do about it...