[R-390] "Fake" 12AX7 tubes on e*pay

[Tim Shoppa]

>>> "ELDIM" <eldim at att.net> 02/17/06 4:36 AM >>> wrote:
> It almost makes me sick to my stomach to think that U.S. Made Radios would
> have to revert to using SOVIET-SINO tubes in these American Classics. Mind
> you now nothing personal against our friends in those countries.  I'd rather
> they be buried by my side than ever have to LIMP ALONG with 2ND RATE quality
> that would jeopardize the radios other precious inards and possibly subject
> them to massive cardiac arrest.

I got started in electronics in the 70's and there were a lot of really crappy
marginal tubes being sold as "new" at the time through retail drugstores and
even TV repair shops too. Rumor at the time was
that they came from Japan or South America but many of the brands relabeled
everything they sold that it was completely impossible to find out who made them.
It's not obvious to me that the Sino-Soviet brands of today are any worse (they're
probably better overall).

Well, looking through my R-390A's that probably never had anything but
mil-spec JAN tubes in them their whole lives I see plenty of heat-damaged
plate resistors in them that indicate past possible tube problems. Worst case
"cardiac arrest" is probably a short that causes so much current in a transformer
or choke and kills it. Resistors and most tubes still seem plentiful enough, and
there doesn't seem a lot of dire shortage of most of a 390A's chokes or transformers
although I'm certain that there are some that are harder to find than others.

Most (but not all) 390A's have fusing that will prevent the worst
many "cardiac arrest - choke fire" cases. (Strangely enough many of the nicer
looking ones on E-pay do not have the fusing installed... MARS units that didn't
see military use/depot service?)

> p.s. Is Tim trying to give a plug for Triode Electronics?  There is no such
> thing as old wives tales when it comes to quality tubes for your

While I've bought stuff from Triode Electroncis with great success in the past,
 I am certainly not trying to push them as a source for tubes... I've had pretty
good luck getting US/Euro JAN tubes much cheaper at hamfests or
even the (I swore I would never talk about it) E-place.

Tim.