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Photoconductive passive preamp?

Has anyone tried a photoconductive cell in place of a potentiometer or stepped attenuator? There's a great article on passive pre's that I found from searching this site on the subject where the author makes mention of this technology used by a commercially available preamp.

I'm about to begin my second DIY audio project, a passive preamp for my system (Snell D, Cardas, Acurus A120, Marantz CC67). I plan on using a simple potentiometer for this which, though not ideal, is cheap (and if my system doesn't work with a passive I won't be out a lot of dough). Eventually (if it works) I plan on upgrading to something a little more audiophile friendly.

The stepped attenuators all seem pricey and the parts to make them DIY ain't much cheaper. So I decided (on a whim) to look up prices for photoconductive cells on digikey and they're quite cheap (price escapes me at the moment, but I remember under $10). I figure that one of these in a box with a small christmas light on a rheostat and you got yourself volume control with none of the problems of a pot but with continuous control like a pot. As long as I understand the specs right there are a couple parts digikey sells which should work in such an application.

Anyone tried one? I did a search for photoconductive and turned up squat.


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Topic - Photoconductive passive preamp? - Chris_F 16:24:44 12/23/04 (12)


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