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1940 Radio has Photo-Electric Pick-up Cartridge
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Return to top of page · Post #: 1 · Written at 6:40:55 PM on 3 November 2014.
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Location: Silver City WI, US
Member since 10 May 2013 Member #: 1340 Postcount: 977 |
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I picked this up at Habitat-for-Humanity charity store last week (they resell donated items)     Radio is 1940 Philco – uses unique light/photocell Pick-up cartridge Stylus vibrates mirror that varies intensity of light to photo cell (photo headshell removed) Light source miniature bulb connected across cathode resistor (lights slowly,shines through Deco-style Catalin-plastic headshell as well as shining “spotlight” on record surface) Sounds very mellow like Optical soundtrack film! Inbuilt rotating SW antenna (photo) Unique Push Pull output uses screen grid of top pentode in triode mode to obtain inverted drive for lower pentode! (never seen that circuit before!) |
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Return to top of page · Post #: 2 · Written at 8:10:16 PM on 3 November 2014.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005 Member #: 1 Postcount: 7395 |
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Sounds like a fairly complicated way of doing things. There was probably more 'bandwidth' on film, as the optical systems for the projectors worked and sounded fairly good, even in mono. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away... |
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Return to top of page · Post #: 3 · Written at 12:11:31 AM on 4 November 2014.
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Location: Sydney, NSW
Member since 28 January 2011 Member #: 823 Postcount: 6761 |
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Nice find! |
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Return to top of page · Post #: 4 · Written at 2:26:10 AM on 4 November 2014.
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Location: Silver City WI, US
Member since 10 May 2013 Member #: 1340 Postcount: 977 |
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This technology stopped by WW II but I think there was a Toshiba stereo photo-electric cartridge in the 1970s or late 1960s. |
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