[sdiy] Speaking of filters with coils...

[aankrom]

They have three terminals. One is a tap. They have a ferrite barrel 
over the outside and a slug inside for adjustment. A local electronics 
store used to have a DMM with inductance mode that they'd let me use, 
but someone bought it. Sometimes I guess at a coil's inductance by 
seeing what a 1kHz square wave looks like when I pass it through it on a 
scope (and compare it with a coil of known inductance and similar 
construction), but that's not a very good indicator. They look like they 
could be anywhere from 400mH to 2H. The organ had a couple of 2H 
inductors on it as well that were used in filters (and they're not very 
big in size). I suppose I could make a filter or oscillator out of one 
of those and then swap in the inductor I want to use and see the 
frequency change. I have an Optoelectronics frequency counter that's 
accurate and precise down to 0.5 Hz. I also have a Wavetek 182A function 
generator and an Radio Shack Optimus EQ with a spectrum analyzer. Not 
the best equipment, but it may help. The frequency counter should be a 
big help at any rate...

The fact that the coil is tapped shouldn't hurt anything, should it? 
I've hear of people using Radio Shack audio transformers as 500mH coils 
in Crybaby clones.

Anthony

On Tue, 3 Jan 2012 16:55:00 +0100, Ingo Debus wrote:
> Am 01.01.2012 um 23:23 schrieb aankrom:
>
>> I have 12 coils that were used as oscillator coils in a Kimball 
>> electric organ. I was wondering if these coils could be put to use in 
>> a filter circuit.
>
> First thing would be to find out their inductance. Do they have two
> terminals, or more?
>
> Ingo
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy