I'm working on a Radiola 26 (third one I've picked up). It had a full
compliment of burned out tubes when it got here, plus the 2uF cap was as
leaky as could be. After replacing the cap, and doing all the continuity
tests on the catacomb, I got to scrounging up enough tubes to test it out.
At first, I could find only four that were usable, but that was enough to
see if the battery and volume pots were working properly. Later, I found one
more tube that I had reglued the base on, that was questionable.
Putting that tube in, I plugged a speaker into the headphone jacks (since
the first AF tube drives the phones). The radio crackled to life, with very
good sensitivity and not bad selectivity, albeit low and distorted volume. I
just wish these radios would tune past 1300 or so..
Well, tired of listening to the low volume from the headphone outputs, I
thought I would try a tube I KNEW to be bad in the final (2nd AF) socket.
The reason I know this tube to be bad is that it's gassy as
aitch-eee-double-toothpicks (almost all of the getter flash is now white and
powdery from the air).
Imagine my total surprise when I connected the speaker to the output lugs
and actually got a decent loud and much less distorted audio! I'm just
waiting for the filament to finally melt open on that tube, but it's a total
blast to see it actually functioning as an amplifier in that condition!
Good thing I've bought more UV-199's.. will be interesting to see how much
better it performs with an intact tube.