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DIY Stompboxes => Building your own stompbox => Topic started by: les_chupacabra on May 07, 2004, 09:20:51 AM

Title: Variable Inductors
Post by: les_chupacabra on May 07, 2004, 09:20:51 AM
Are there any low price low power variable inductors suitable for pedal boxes?  Everything I've seen out there is high price high power.  Just thinking about playing around.

Thanks.

John
Title: Variable Inductors
Post by: R.G. on May 07, 2004, 10:27:15 AM
There are no low price variable inductors commercially available, to the best of my knowledge.

About the best you can do is to use a gyrator circuit to emulate an inductor with Rs, Cs and gain.
Title: Variable Inductors
Post by: les_chupacabra on May 07, 2004, 10:34:54 AM
Thanks R.G.  I'll look into it.

I was listening to some Jimi Hendrix Electric Ladyland this morning and how smooth his top end was and thinking about how he wrapped extra length of cord into coils for some high end rolloff.  I'm guessing that has something to do with pure nickel strings, board eq, etc. but I was thinking that the extra length of cable would add capacitance and the cable coiled up had an inductance effect and all of it together forms some kind of passive HPF.  That's based on my rudimentary understanding of all these things - correct me if I'm wrong.  

Anyway, I was thinking it might be fun to build a little box w/ a couple different cap values and a variable inductor and see what happened.  Mix and match to taste and TBP if you wanted it out of the mix.
Title: Variable Inductors
Post by: rocket on May 07, 2004, 12:06:59 PM
I THINK that a coil of coaxcable has no additional inductance because it's bifilar. just try a few different caps in the 500pF to 2000pF range - you can make the switchable wih a rotary switch, you can mount it into the guitar.
Title: Variable Inductors
Post by: Paul Perry (Frostwave) on May 07, 2004, 07:46:54 PM
There seems to be some confusion in this thread between caps & inductors..
but, if you want a low cost switchable inductor to experiment with, you could try those multitap power transformers. Or make a box with a number of coils that can be switched in series, like a resistance substitution box.