Unusual use of speaker autoformer

discussion of magnetic volume control design for both line and speaker levels.

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Mrdean
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Joined: Sun Jul 19, 2020 7:12 pm

Unusual use of speaker autoformer

Post by Mrdean »

I mentioned this to Dave by email, but I thought I would post it here in case someone else is curious. I have some piezo film tweeters that need a transformer to up the voltage to get them to operate at reasonable output levels. I inquired as to whether an autoformer hooked up backwards could be used to increase the signal voltage. The Piezo film is essentially a capacitor. I then took some old in-wall “volume control� autoformers to use as “Guinea pigs�. Sure enough, hooking them up backwards does increase the voltage into the piezo, but there is a limit to How much output I can get. These autoformers use silicon steel interleaved laminations of unknown quality. Now I am curious to see what improvements can be made using better laminations (permalloy). Anyone with similar experiences?
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