Looking At Wah Pedal Inductors with a DIY Curve Tracer

[@TheQShow]

This was really cool! Love the idea of a diy curve tracer, thanks for making this :)

[@VegasCyclingFreak]

Thanks. Will be doing a video on the making of the curve tracer soon.

[@3rdtonefromthesun]

Interesting video, the thing is with wahs is that everything is balanced against the other components in the circuit. Different inductors do have an affect not only on the tone but the feel as well. As I say, they’re highly balanced circuits and in certain positions the wrong type of component can ruin the sound or feel of the wah.

[@VegasCyclingFreak]

@@3rdtonefromthesun I’ve messed around with modding the classic wah pedal circuit. The most audible change to the sound was the transistor used - how much gain it has basically, which alters how the circuit responds to what is going thru it.

[@3rdtonefromthesun]

@ indeed it does, but as it’s a multi-factoral thing your signal chain is equally important. Some wah setups don’t suit certain applications or rather, work very well with them. But for juicy pure wah tone, a good edge of break up amp has to be key ingredient, metal territory gain with a wah to me devalues the nuance you can get out of them - they end up often sounding nasty. They’re a very driven pedal and no two players sound the same underfoot, that’s another key component in the signal chain hahahaha…

[@darwinsaye]

My 70s Shin Ei Wah has some kind of an audio signal transformer (I think using just one side) rather than an inductor like any of these. Sounds like a Wah.

[@VegasCyclingFreak]

Yeah those are a quirky wah pedal. I'm sure that was probably done as a cost saving measure. You can use audio transformers as an inductor, they just need to have the correct amount of inductance to make it a resonant circuit. I should look at an audio transformer sometime, using similar test arrangement and see what that looks like.

[@jw228w]

thanks for this great study.i have xy on my scope and trying to understand what variables a component part reacts to different changes in voltage,resistorsfrequency, etc.cannot find any theory books on the curve tracer idea if you have something you could share that would be great. thanks John

[@VegasCyclingFreak]

There's not a lot of in depth stuff out there in terms of using o'scopes in this manner but maybe these pages will help: www.testandmeasurementtips.com/using-scope-display-lissajous-patterns/ resources.pcb.cadence.com/blog/how-to-read-lissajous-curves-on-oscilloscopes Curve tracers can be a good way to test things like transistors and capacitors in circuit. I have even determined approx. resonant freq of guitar pickups for which I can't find any specs.