[AMRadio] 7A4/XXL Tubes

W5AMI ars.w5ami at gmail.com
Thu Apr 4 21:36:50 EDT 2013

Anyone have a stock of loctal XXL or 7A4 tubes?  I am in need of a couple
that test good.  Been through about 5 in the last month that all check very
weak on my TV-3/C tester.  A certain vendor told me that tube testers are
basically a myth in regard to accurate readings.  I got two from this
vendor that both checked weak, and one even had a short from plate to
grid.  He sent me a replacement for the shorted tube.

I have gone ahead and put them in an old rx I'm working on that I've
re-capped and replaced all resistors, new wiring, etc., but getting oddball
results on the BC band where I can not find a suitable fundamental signal
from my generator.  Seems the problem lies in either the RF/mixer or the
Osc sections and it just so happens both of those sections use an XXL.  Not
sure they are really the problem, but it would be good to know I had two
good tubes in there before I chase a wild goose elsewhere.

Anyway, if anyone has a couple of XXL/7A4's that test good, I would sure be
interested.  Email me direct and tell me what you want for them.

Brian / w5ami

"Who feeds a hungry animal feeds his own soul" - Charles Chaplin

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