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previous: AMZ For anyone who is interested in usi... -- 8/27/1999 10:34 PM

Re: Wah inductor source

8/28/1999 4:08 AM
R.G.	Re: Wah inductor source Thanks for the help Jack. The 1386 number is what is printed in the article on the Wild Mouse, which is the source I used for reference. When I picked up one from the Shack today, they told me that they've always been 275-1380's so apparently the article in "Electronics Now" is in error, although the pinout information in my Wah Pedals article is correct as noted. In any case, Aron asked for some pictures on how to use these things; that's why I picked one up. I'll be posting pictures of the 1380 showing which leads to use. I'd let you see them now but I left the &$%# diskette at the office. Yes, since posting the Wild Mouse review and the Wah article I've heard by both email and posting that an assortment of small audio transformers might be in the right range for a wah. The primary inductances should be about right in that range. In fact, now that we know how the wah circuit works in some detail, we can make intelligent tradeoffs between L and C values vesus impedance level and probably get a range of inductors to work. By all means, run us a survey and let us know which will work in this application. It'll be a nice addendum to the Wah article. I'm not too surprised that the iron cored audio transformers aren't as smooth and harmonically pleasing as a real wah inductor - I would not have thought for an instant that they would. The harmonics of the fabled Fasel wah inductors come from a core material property, as my article states, and I suspect that any smoothness from other wah inductors may as well. Iron is a fundamentally different ferromagnetic material than the various ferrites, and the saturation flux densities and sharpness are different. However, the availability of pre-wound transformers with a secondary winding opens the way to some experimentation that might be interesting. Feeding a current source through the secondary winding gives a way to introduce a magentic bias on the cores, and may let us move the iron to a place that has some slope to the BH curve as well as even harmonic generation, as I noted for the Fasels years ago in spectrum tests. By the way, Jack, I've been meaning to ask - does signing all your posts "AMZ" increase your web traffic? You think it would help me to sign all mine "GEO"? What do you think? R.G.

8/28/1999 4:08 AM

R.G.

Re: Wah inductor source

Thanks for the help Jack.

The 1386 number is what is printed in the article on the Wild Mouse, which is the source I used for reference. When I picked up one from the Shack today, they told me that they've always been 275-1380's so apparently the article in "Electronics Now" is in error, although the pinout information in my Wah Pedals article is correct as noted.

In any case, Aron asked for some pictures on how to use these things; that's why I picked one up. I'll be posting pictures of the 1380 showing which leads to use. I'd let you see them now but I left the &*$%#* diskette at the office.

Yes, since posting the Wild Mouse review and the Wah article I've heard by both email and posting that an assortment of small audio transformers might be in the right range for a wah. The primary inductances should be about right in that range. In fact, now that we know how the wah circuit works in some detail, we can make intelligent tradeoffs between L and C values vesus impedance level and probably get a range of inductors to work.

By all means, run us a survey and let us know which will work in this application. It'll be a nice addendum to the Wah article.

I'm not too surprised that the iron cored audio transformers aren't as smooth and harmonically pleasing as a real wah inductor - I would not have thought for an instant that they would. The harmonics of the fabled Fasel wah inductors come from a core material property, as my article states, and I suspect that any smoothness from other wah inductors may as well. Iron is a fundamentally different ferromagnetic material than the various ferrites, and the saturation flux densities and sharpness are different.

However, the availability of pre-wound transformers with a secondary winding opens the way to some experimentation that might be interesting. Feeding a current source through the secondary winding gives a way to introduce a magentic bias on the cores, and may let us move the iron to a place that has some slope to the BH curve as well as even harmonic generation, as I noted for the Fasels years ago in spectrum tests.

By the way, Jack, I've been meaning to ask - does signing all your posts "AMZ" increase your web traffic? You think it would help me to sign all mine "GEO"? What do you think?

R.G.

Replies:

AMZ q{the availability of pre-wound tra... -- 8/28/1999 2:32 PM
Tobias Karlsson Mr R.G said;....Feeding a c... -- 8/28/1999 7:57 PM