[R-390] Tube testers and other babblings

[Barry Hauser]

Hi Scott:

You wrote:
>   Is the B&K tester worthy and accurate ? If not, is there a certain
tester
> that would serve me better?

You didn't mention the model -- like "your mileage" they vary, but quite a
few are good.  The last tube tester made of any (I think) was the B&K 747.
Do you have the manual including calibration instructions?  Tube charts?
Might help the list assist you if you let us know on the model.  May well be
good enough, however, as I recall, B&K also made some cheap emissions
testers (i.e. not mutual transconductance).

If they're not already installed, you might want to chase down some "socket
savers" -- primarily for the 7- and 9- pin sockets, unless it's one of those
tester designs with multiple "quick-test" sockets of the same type.  In that
case, wear may have been spread out over a bunch of the 7- and -9 pin
sockets.

> All of the tubes I have bought look new. Should I test them all? Does
> testing the tubes put wear on them?

As long as the tester is OK, not much harm in testing them all, but keeping
them on the tester too long is not a good idea.  You should test just prior
to use, however, you might want to test them all so you will know how many
good tubes you actually have on hand.  A few things to keep in mind:

1.  Make sure the shorts lamp(s) work and always do the  shorts test first
and make sure you watch and don't blink.  Unless the tube is of the
do-not-tap type (like expensive 1L6's, and maybe the 26Z5W's) tap on the
tube to watch for flashes.  If there is a short -- don't go any further with
that tube, it may well damage the tester. A shorted replacement tube can
also damage your receiver.

2.  Triple-check that you have it set to the correct filament voltage.  Also
a good idea to test in order of filament voltage -- where applicable -- all
the 6 volt, then 12, then whatever.  In other words, don't test the 26Z5W's
first and then go to the others, if you think you might forget to flip the
fil. switch.

3.  Set it up to check a number of tubes of the same type, as Joe suggested,
to save wear and tear on the switches.

4.  Keep the tube in long enough only to do the shorts test and then if OK,
the quality test as long as it takes to get a stable, or good enough
reading.  Don't park the tube in there and let it sit or fall asleep with
the quality test on.

5.  If the tester hasn't been calibrated, test the tester with known good
tubes to get a general idea.  If it tells you a variety of good tubes are
bad, it needs work or at least recalibration.  If it tells you all of your
tubes or all of a type are shorted, that's another problem.

> Most of the tubes I bought are JAN tubes. Some are GE. I also got some
> 5814A's made by National Gold Line. Is it OK to use the National tubes if
there are some
> JAN's or GE's already in the radio or does it matter if one would mix and
match?

No, however, some like to optimize by swapping tubes of the same number
around between sockets -- tube tweaking.  Also, it's best if the PTO tube is
not too hot/strong.  If it reads middling, leave it in there.

> Lastly, some of the tubes that I bought are dated back to the 40's.
> Should I save these?

Yes -- you may experience an expanding interest in hollow state gear and
some rather gothic looking black wrinkle radios may materialize on your
bench.  If not you can sell or trade them.

> It seems that they would be collectible.

Yup, as I mentioned, BC-312's, BC-348's and some ol' Hallicrafters, etc.
like to "collect" them.  I can tell because, when I open them up, that's
what's inside. ;-)

Those are not particularly collectible in the real sense.  Older tubes from
the 20's -- silvery 4-pin globe shaped ones may be, even if not working.
Not necessarily all that expensive, though.

>
>   Thanks for any advice.

Y' welcome

Barry