[ARC5] Glass or Metal Tubes Preferred for Receivers?

[D C _Mac_ Macdonald]

Is there a performance and/or lifespan difference between the tubes?  I.E., 12SK7 or 12SK7GT preferred?


73 de Mac, K2GKK/5
(Since 30 Nov '53)
Oklahoma City, OK
USAF Retired 61-81
FAA Retired 94-10

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