GB> toobs-add a mystery Sylvania to the list! :-)

Kenneth Laine Ketner ketner at ARISBEASSOCIATES.COM
Sun Aug 17 10:35:28 EDT 2003

John: In my GE tube book, ESSENTIAL CHARACTERISTICS, on page 222 (see
also page 379), type 5647 is listed as a subminiature type,
high-frequency diode, basing 5647 (page 465, cathode yellow, plate blue,
other 2 are heaters), outline T-X (page 348 f., especially 375), 6.3
volts filament at 0.15 ampere. I have some “flying lead” tubes, also
called pencil tubes, or sub-miniature, and I find many of them with 4
digit type numbers, many of which show up in the GE book.

I have several tube books, and by far the most comprehensive and useful
(except for transmitting types) is ESSENTIAL CHARACTERISTICS.

I haven’t been able to find any listings for CK pencil tubes. All I know
is that they are Raytheon. Maybe some Raytheon experts can help on


Ken Ketner
ARS KA5ELD (Extra Class)
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