My Varitone sounds the same without the inductor. What's wrong?

[deadlock]

Hi. I joined this site just to ask this question. I'm stumped.


I made a vairtone (minus the inductor) and it worked.


Then I used the primary of a Radioshack Audio Output Transformer as an inductor (i read on this forum that this can be done). I have the inductor wired in series with the caps (on the ground side.) It sounds like it did before I rewired it with the inductor - just a low pass filter. It seems like a simple thing to make, what am I doing wrong?

[52 Bill]

Welcome to the place. Your problem could be any number of things, wiring error, not the right inductance from your transformer, etc.

I've tried using the Radio Shack transformer for different things, and some of them work and some of them don't. If the transformer is wound in such a way as to minimize the inductance, then using it in your circuit will cause a lack of depth. Once a few years back, I found that the transformers that were marked Taiwan worked well, but the ones marked China didn't. Different suppliers different results.

Maybe try a different transformer.

[deadlock]

Thanks.

I tried hooking the transformer to a toggle switch so I could bypass the transformer. Once I did that and was quickly able to switch between having the transformer and not having it in the circuit, I realized it actually does effect the sound! Problem is, it's SO subtle. At least this means I didn't wire anything incorrectly, I just need a different inductor.

I don't know much about inductors. I believe people normally use 1.5H, 3H and 7H for varitones. I was told that the one I'm using is only .5H. How does this effect the sound? Would a 7H allow more highs through?

[David Schwab]

It's been years since I used that RS transformer for a Varitone. Craig Anderton list a transformer from Mouser, part # 42TM019:

42TM019-RC Xicon Audio & Signal Transformers

Http://www.smallbearelec.com/Detail.bok?no=745

Here's the Anderton circuit.

[52 Bill]

Inductors will allow low frequencies to pass through them while rejecting higher frequencies, just the opposite of a cap. In the traditional Varitone circuit the midrange is changed the most.

If I remember correctly, the original Gibson choke value was 15 Henries. I too have seen versions of the circuit that use the values that you mentioned. I think that Gibson used a 1.5H choke for the midrange control on a few of their models, like the Howie Roberts.

If the RS transformer is rated at 500mH (.5H) then it is more usable for a wah inductor than for a Varitone.

[David Schwab]

Inductors will allow low frequencies to pass through them while rejecting higher frequencies, just the opposite of a cap. In the traditional Varitone circuit the midrange is changed the most.

If I remember correctly, the original Gibson choke value was 15 Henries. I too have seen versions of the circuit that use the values that you mentioned. I think that Gibson used a 1.5H choke for the midrange control on a few of their models, like the Howie Roberts.

If the RS transformer is rated at 500mH (.5H) then it is more usable for a wah inductor than for a Varitone.

The inductor on the Gibson Varitone was 1.5H. Interestingly, the choke used in the L-6S and L9-S was made from a steel bolt, three washes and a nut!

Here's the L9-S Ripper