The Kay "Wah Wah"
Last updated 3/16/24
By Paul Marossy
This somewhat obscure red plastic wah pedal has intrigued me for many years. I think I first heard of one about 20 years ago. What I found fascinating was
that it utilized a variable inductor, which is unlike 98% of the other inductor based wah pedals out there, that use an inductor with a fixed value. I believe
the only other wah pedal that utilized a variable inductor was the Univox UniWah.
It was
difficult to get any real detailed info on it by searching the internet. Before more sites like Reverb existed, ebay was the only real place where these
could be found and they would pop up very infrequently. When they did, the asking price was usually ridiculous. I obtained mine via Guitar Center for a
price that was less than half of the usual asking price, in an unmodified condition and in quite nice shape for its age. It is an interesting little pedal. It
seems almost like a toy but it's fine for studio use at least. The plastic shell is far more durable than people think it is but it's not as heavy duty as the
Univox "Uniwah". It is interesting how a wah pedal circuit like this can be made with such few parts. Another quirk about this pedal is that it operates on 1.5V,
provided by a single "C" size battery.
I tried to research the back story on these Kay guitar pedals but info on these seems to be pretty scarce. Apparently there was also an orange Fuzz Tone, a blue Tremolo and
a black Bass Boost pedal offered as well, all of which used the same basic enclosure design and had a potentiometer operated by the treadle. I am not sure of the date of manufacture on these devices, which were made in Japan. The general consensus is they are from the 60s but I think it is much more likely that they are from the very late 60s and/or early 1970s. I have seen one reference to the Kay wah pedal saying that it was purchased new in 1974 and it was "still going strong" in 2017. They were probably offered for around a third the price of a Uniwah, for example, which had a list price of $45 back in the day.
Below are some details of my Kay "Wah Wah" pedal.
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I think these pedals look kinda cool. Supposedly this the favorite wah pedal of U2's guitarist, "The Edge". It is true bypass, but you have to manually bypass it using a slide switch. Would be awkward to use live without some alternate means of bypassing, such as an external bypass box. |
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Looking at the inside, it's apparent that it is very simple. The PCB is vertically mounted and fits in slots molded into the enclosure. The flat spring assembly is held in place by standoffs that were melted flat. One of those broke off in my example, leaving one corner of the base a little loose. I fixed it by drilling that out and adding a small screw to secure that corner. |
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The bottom of the enclosure is simply a rubber piece that attaches to lips on the perimeter of the bottom of the enclosure. The one on my example was in surprisingly good condition, still pliable and not cracked. This arrangement is not that secure when it comes to the battery staying in place. However, that also depends on if the battery contacts are installed correctly. They fall out easily when you have the bottom off. If you put one of these contacts back incorrectly, one end of the battery tries to pop out. It's easy to do if you're not paying close attention. |
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There is a schematic included inside. As can be seen, it's an amazingly simple circuit which operates on 1.5 volts. I have seen some examples where people changed it to use a 9V battery, like it's some kind of upgrade. It's not. The circuit was designed to operate on 1.5V, and I do not recommend doing this. An equivalent to the 2SC828 transistor is a 2N3904. |
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Here you can see the flat spring actuator. It's simply a partially threaded screw that has an eyelet on one end which attaches to the treadle, and on the other end is an arrangement of stacked washers and two nuts, one of which secures a connection to ground. I surmise this was done to prevent that flat spring assembly from becoming an antenna. One benefit of a variable inductor arrangment is that there is no potentiometer that will eventually wear out, but on the other hand they can be microphonic. I've had fixed inductors also be microphonic on ocassion too. |
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The inductor can be seen here. It is a very similar arrangement to the Uniwah. The position of the weak disc magnet (or possibly it's just a ferrite disc) in relation to the ferrite cup that the copper windings are in determines the amount of inductance. Between both extremes of the treadle, the inductance measured between 140mh & 3H and the DC resistance 135 ohms. Toe down position is the least amount of inductance. In this case, in heel down postion, the actuator is pulling up the end of the flat spring assembly whereas in the Uniwah it's being pushed down. Interestingly, this inductor is considerably smaller in physical size compared to the Uniwah, and very small movements cause much larger changes in the inductance. |
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The component side of the PCB. Not much to see here, huh? |
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Foil side of the PCB. Interesting to note that notch made for wire(s) to pass under. |
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Of course, the Kay logo is one cool feature of this unusual little wah pedal. |
I am happy to have finally acquired one of these pedals. I was mainly interested in the physical features of it - how it works, etc. but I
think it's also not a bad sounding wah pedal. It has a very distinctive sound and it takes a little getting used to very small movements of the treadle having
such a large effect on the sound. It also depends on if you are using it with distortion or a clean sound.
Like with all wah pedals, in my experience, it depends on the context it is used in, and what works
best for certain situations. I tend to prefer the less extreme sounding wah pedals so that when used with a lot of gain they don't become too harsh
sounding for me to withstand hearing it.
One thing to note on these old Japanese manufactured wah pedals and guitar effects is that some of the component values can drift pretty wildly with age.
In both of my Uniwahs for example, the small value electrolytics were all way out spec, typically by 50%! Also several of the carbon comp resistors had
drifted way out of spec as well. My Shin Ei "Companion" wah was the same story... the electrolytic caps had drifted far from what they were supposed
to be. My Kay "Wah Wah" was no exception. The 10uF input cap for example measured only 4.7uF. In all these examples I had to
replace these components to get the circuit to work and sound as it was designed. So all that to say, don't
judge these old Japanese guitar effects until you know all of the component values are still what they are supposed to be after 50 years, because these
components being so far out of spec will definitely affect how they sound!