The Invention of the Wah-Wah pedal | Hacker News Reader

The Invention of the Wah-Wah pedal

priceonomics.com

51 pointscalebgarling10 comments

Interesting article, although the LC circuit (resonant low pass circuit) is something I would teach my students as a phys lab TA, I feel like the key is the inductor and the cap more than the pot. The issue with the MRB costing more was that the switch in the MRB was to switch between 3 different cap values: http://www.voxshowroom.com/ct/amp/us/features/mrb.jpg which would be expensive. The wah circuit changes the amperage (current) to the cap instead, making it act like a different value. (explained here: http://www.geofex.com/article_folders/wahpedl/wahped.htm#wha... )

Also a side note, if you want a variable wah without the footpedal you have a couple of options: http://diy.smallbearelec.com/Projects/WMouse/WMouse.html or build an envelope follower (which is neat because it triggers off of the amplitude of your signal, aka how hard you are strumming, which is nice for people w/ bad foot coordination) with a settable Q/freq: http://buildyourownclone.com/products/envelope-filter-fixed-...

Other neat innovations: zvex wah-probe (theremin circuit controlling the wah freq) and the zvex seek wah (a sequence of different wah settings you control). anyway, wah-wah's are fun and chances are if you did a set of physics electricity labs you built one already, just without the transistor choking the cap.

"In 1965, electric guitarists really only had four different effects pedals available to them: tape delay, tremolo, spring reverb, and fuzz (distortion)."

Of course this didn't stop "old-school" guitar players like Linc Wray and later Neil Young from cranking up the Amp, and moving the guitar close to get feedback.

Valves really give off a special sound. Another Linc Wray idea: punch holes in the speakers with a pencil to get that "distorted sound". Rumble, 1958 ~ http://www.youtube.com/watch?v=bjs5QWjvNWc and Linc talking about the sound ~ https://www.youtube.com/watch?v=kKjjb8RmcgA

The article links to this documentary put out by Dunlop, which is pretty fun: https://www.youtube.com/watch?v=A0A8cPj_fPo

> Plunkett realized that he could replace this pricey switch with a potentiometer -- essentially an adjustable knob that divided voltages and acts as a variable resistor -- and achieve the same effect. “The switches were very expensive -- about $4 each,” Plunkett continues. “The potentiometer would only cost about 30 cents.”

Maybe he's talking about a rotary switch coupled to numerous external components? Such a thing has tonal virtues: you can switch paths that have different L, C and R values.

But, no; it's just described a simple switch:

> This switch, invented by British engineer Dick Denney and installed on all Vox AC-100 amps at the time, stood for “middle range boost.” When flicked on, it would highlight the middle sound frequencies of the guitar (notes between 300 and 5,000 hertz); in doing so, it would tame the extremes (very high and very low pitches), and produce a flattened, smoother sound.

It seems like nonsense that some at most DPDT switch would cost $4 versus a potentiometer at $0.30. Not for equal quality.

Maybe someone can shed some light on this?

The circuit and a photo of the MRB control is here:

http://www.voxshowroom.com/us/amp/RG_FSconnectors.html

It seems to be a rotary switch. I can believe that the pot had a significantly lower unit price than the switch, especially if the amp used lots of pots and only one rotary switch, or if the rotary switch was custom made.

Yeah tried to mention that in my comment. You were switching between 3 physical caps, but the transistor(s) in the wah circuit let you use a potentiometer to alter the way the cap reacts in the circuit by reducing the sheer number of electrons that even get stuck on it.

Good switches have always been expensive, possibly because they have a lot of small moving metal parts.

Pots are made with lower mechanical tolerances and are easier to build, so they're usually cheaper.

There's an awful lot of hype in this article.

Tunable peak/notch tone control circuits had been around since the early valve days, and the effect was well known to recording engineers and synthesiser experimenters.

When the sound became popular, there were dozens of circuits published in the electronics hobby magazines, particularly in England where it was known as a "Wow pedal".

Ref: Someone who was there.

Yeah they were fundamental to the tuning of radio at all come to think of it. Formant filter synths were available far earlier. And even earlier than that wah-wah mutes on trumpets were commonplace in the 20s which were a physical manifestation of tunable peak low pass filters: https://en.wikipedia.org/wiki/Wah-wah_(music)

When I think of Wah-Wah in the late 80's I think of "What I Am" by Edie Brickell and New Bohemians: https://www.youtube.com/watch?v=tDl3bdE3YQA

The little solo in there uses it in a very melodic way.

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