FCSG: Wonderful to speak with you again Mad Professor. I heard the other day that you are modifying Rocket Ride Wah pedals for Custom Sounds in Finland. I have heard that having Tropical Fish Capacitors in Wah's is one of the ingredients to getting that Jimi Hendrix Wah sound right.
BJF: Tropical Fish... yes, those were known as 'Bon Bon' capacitors due to how they look (just like Candy). They were originally used in all types of consumer-grade electronics, including Wah pedals. If they are in your Wah it would indicate when it was made, judging from when this type of capacitor was an 'off the shelf' item. One thing to consider is that Tropical Fish capacitors are fragile at the ends where the legs join the body. Considering the way Wah's were generally used they could also lead to unnecessary noise, hum, radio interference and because of this they can also be troublesome.
Oh, I've just designed the modification for the Rocketride Wha aswell as other Rocketride Effects while I don't preform the modifications www.rocketride.com
FCSG: Wah's are discussed online, and apparently there is more than one way to build a Wah pedal... including a Vox Style Inductor-based Wah, a Twin-T Circuit, Multiple Feedback Opamp Active Filter Circuit and 'State Variable' Style Circuit like the Mutron 3.
BJF: Yes, there are many ways to make a Wah. We can get the Wah effect by a moving low pass filter with resonance (this means a filter that cuts frequencies above a corner frequency at a certain rate per octave, but at the corner frequency there is a peak... or a moving midnotch filter can also be used. The point of using a low pass filter would be to keep content below corner frequency relatively intact, or the sound can become thin. A similar sound can be achieved with a phase shifter since those operate by moving midnotches up and down and resonance can also be introduced. There are of course many Wah variants and circuits that don't use inductors. Avoiding the use of an inductor would of course be attractive since they are expensive, and are also a bulky component that is actually highly sensitive to magnetic fields.
FCSG: Of course I love Inductors. I personally would prefer a Wah to have a good inductor, and... of course... FISH!
BJFE: Yes, in fact... inductors of suitable sizes are rarely used these days in any electronic equipment anymore... as a sidenote, Aleksander Neimand of Tubewonder amplifiers told me they used tape recorder heads for inductors in Wah's many years ago in Poland since there was one head that had about the correct properties, and inductors were hard to find. These days though, if you want an inductor you can order a suitable one as there are specialty suppliers for this.
If you are looking at a Wah cicuit, and are wondering what parts to make an effort to put in, I'd recommend looking at the gain of the first transistor, and this can be adjusted via the emitter load, if necessary. Also look at the components around the feedback network of the first transistor.
FCSG: I was looking at Teese Wahs... but read somewhere that they can develop dead spots at either end of their travel... what can you say about this please?
BJFE: Dead spots along the travel of the pot indicate something could be wrong with the pot and this is also the part that wears out in the Wah first. Replacing the pot properly requires placing the cogwheel and the tooth bit so that there is a tiny/ minimal gap so there is no pressure to the rotor from the side, or the pot will soon break again. One can also place a small amount of grease in the gap to make the Wah run smoothly.
I think Teese would be most helpful in assisting anyone with such a problem. There are about ten Teese Wah's here in the shop, and none of them here have any signs of the dead spots you mentioned... with the internet, this type of thing can become overblown.
FCSG: My dream Wah would have been a brand new Clyde McCoy-like Wah... with tropical fish, and NOS inductor for instance... but now I might be inclined to consider making some changes (after all you have said...).
BJFE: Have you ever played a McCoy Wah?
FCSG: Yes, a friend of mine who spent his life playing the Blues with a Les Paul swore by them ... and I think he got one of the 'good ones' (I know it was hit and miss)... he let me try it out... I was a kid at the time, and thought one Wah sounded like another...
BJFE: Once more thing about the tropical fish... some 25 years ago or so, I'd walk down the street and buy some from the local radio repairman... I thought they were pretty...but if I built a Wah today, I would certainly use some other type of plastic caps/ films. They can do all Fish can do, and more. Fish were meant to be easy to read due to their color coding, although the last band sometimes got hidden. And as I said, the leg joint to the body is a bit fragile and some of those Bon Bon's therefore have expander bends on the legs, to absorb vibrations. Phillips made another capacitor that was orange but built in a similar way... but I haven't seen those in many years. The legs can come of these capacitors near the body due to vibrations in transportation.
The most common problem with Wahs though is worn down pots and switches. Of course, these are mechanical parts that see heavy use/ stress.
Most old effects for guitar use Pertinex circuit boards... which can also crack with time, and due to vibrations.
In the 1970's, glass fiber boards were twice as expensive, and only used in expensive equipment in those days... meanwhile, you hardly ever see anything anymore with Pertinax boards anymore unless it is something with very low life expectancy.
FCSG: Yes, when I was a kid in the 70's I had some Walkie Talkies, that had the glass boards in them. Is there anything else that breaks down in Wah's that you come across?
BJFE: I think, other than what I mentioned, maybe some jacks and battery clips, and sometimes electrolytic capacitors... and there is one specific one that if it dries out it turns a Wah into a swell pedal (!).
to build a Wah to someone's order is a very personal thing. It can be a very personal effect. There are many way it can be done... of course Aleksander lived near a factory that made the tape recorder heads, and there are none of those left anymore!
I can see that would work very well, due to shielding and also that the inductance was right spot on too.
I was at a guitar show a few years ago, and was asked to Demo some Wahs. I had to take a second to recall when I had last played a Wah publicly... and maybe it had been 15 years! Often I'd use a Bud Wah with a Strat due to the fact it is 'middy', but this particular day, I was sitting with my Les Paul*, and found the Wah's at my disposal were the Mollon Wah... which was more pleasing because of the tone... more Vintage, and thinner... as you can see, what guitar you are playing with the Wah can have a big effect.
*Oh and if we are going to be exact it wasn't my own Les Paul but one supplied by the distributor I was representing ;)
as a sidenote
I used the same guitar to demonstrate the LouderandMore amplifier at the same show, while that's neither orderable through Custom-Sounds. Harri has one though.
I mention it only because I do see it would seem that anything I design or make would be orderable through Custom-Sounds but that is not necessarily the case.
