#61
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I think that would be difficult to answer unless someone was involved back then.
I'd guess that seleniums were still viewed as reliable. You wouldn't have to deal with the 3 amps needed by the 5U4 heaters, seleniums take up less space and run cooler. I think the space issue was why the Sylvania 1-128 used selenium rectifiers in addition to a 5U4 and 7X6. John Quote:
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#62
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OH yes! Good point John. I forgot about the need for the seperate 5v filiment winding on the transformer. Now it makes more sense. I think this was more likely a matter of ecconomics than anything else. The transformers on the CT100 thru CTC4 series were already extremely large without adding an additional 5V winding for the 5U4's.
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Vacuum tubes are used in Wisconsin to help heat your house. New Web Site under developement ME http://AntiqueTvGuy.com |
#63
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I would also say power consumption/heat generation was the reason. By the time the CTC-5 was developed, the tube count and power consumption were reduced enough. I bet the selenium rectifiers were more expensive than 5U4s at the time.
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Chris Quote from another forum: "(Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did." |
#64
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Actually, they went back and forth till silllycon was proven reliable. CT-100, 21-CT-55 and CTC-4 used selenium. CTC-5 had 5U4's, early production CTC-7's had 5U4's and later switched to silicon, and everything from CTC-9 onwards used silicon as well. I suspect that the development of cheap silicon rectifiers was a driving force in the engineers decision making process.
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Evolution... |
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