Nice, cheap wah inductor

[.Mike]

Hi folks,

Since I'm still pretty new at this and trying to learn as much as possible, I have been enjoying building circuits on my breadboard.

I came across a pretty nice inductor at Mouser that I thought I would share. I haven't seen anyone else use it yet besides me.  To my ear, when compared side-by-side, it sounds much better than the Mouser #42TM013 transformer, which has been recommended as a workable cheap inductor.

It's the J.W. Miller Varnished RF Choke 500mH 5%, Mouser part #70F501AF-RC. $2.86 each. Here's a photo:



I am using it on my breadboard right now as part of the Basic Wah Circuit as I go through the wonderful The Technology of Wah Pedals article on R.G.'s site.

The only part that concerns me is that the inductor is spec'd to have a maximum resistance of 736 ohms, whereas the wah article says most inductors measure 40-75 ohms. Mine measures 618 ohms. I'm not sure how this impacts the circuit, if at all. My hunch is that, because the inductor is in series with a 470k resistor, the difference between 470,040 ohms and 470,618 is minimal. I'm also not sure how it impacts the function of the 33k resistor (Rq) that is in parallel with the inductor, or the 82K resistor (Rb2) or the 4.7uF electrolytic (Cbp) that connect to ground.

There is a lot of interference in my house and I am using an 8ft lead of Cat5 between the breadboard and the actual treadle assembly, so it is very, very noisy, but it still sounds pretty good. If anyone wants to hear the difference between this inductor and the 42TM013, I would be happy to record a sample, keeping in mind that there will be a HUGE buzz in the audio.

Anyways, check it out if you are looking for a nice, cheap wah inductor, or just something different.



Mike

[Exactopposite]

have you compared it to any inductors that are made for wahs?

[.Mike]

No, I haven't.

Honestly, even though I started playing 18 years ago, I was never really into effects. I played a "real" wah (a Morley) once back around 1994, and I had an Akai Variwah that I played for about six months before it went belly up. I'm afraid I couldn't even begin to make a comparison.

For a few bucks, it might be worth it for someone with a real wah to give it a go with their next Mouser order. Maybe it's a pure mojo... heh!



Mike

[bancika]

My hunch is that, because the inductor is in series with a 470k resistor, the difference between 470,040 ohms and 470,618 is minimal.

that's what I thought but later I heard that it's not really like that. IIRC internal resistance affects Q. Doesn't necessarily have to be worse than the "real" inductor, but may be different...

[igor12]

I'm trying the same inductors right now.  I too get a lot of buzz.  Sounds like some sort of shielding type buzz.  I'm almost positive it's due to the inductor, since my breadboard is shielded pretty good and I haven;t really had any shielding buzz with previous experiments.  ANybody got any theories?