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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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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)
- Re: Photoconductive passive preamp? - softsupply 16:02:05 12/25/04 (0)
- How about... - tesla 19:38:13 12/23/04 (0)
- Melos had such a scheme before... - pmkap 18:59:46 12/23/04 (5)
- The Melos Photentiometer sucks!! - eargasm666@yahoo.com 20:13:56 12/23/04 (1)
- So I guess that's why nobody uses 'em (nt) - Chris_F 04:33:52 12/24/04 (0)
- That's cool....but.... - doodlebug 19:53:52 12/23/04 (2)
- Re: That's cool....but.... - Chris_F 04:36:10 12/24/04 (1)
- Neat idea......n/t - doodlebug 10:05:30 12/25/04 (0)
- Re: Photoconductive passive preamp? - SysInfo 18:26:37 12/23/04 (3)
- Really! - clifff 04:03:16 12/24/04 (2)
- No way. - SysInfo 20:42:21 12/24/04 (1)
- use mechanical prism/mirror or electronic control to steer light between 2 opto-resistors. nt - Alex S 23:20:09 12/24/04 (0)