Tube flash

A tube tester won't apply the full B+ voltage testing a tube. Even the top testers won't if the user doesn't know all the operating parameters of your amp.A lot of newer amps drive tubes a lot harder then they used to back in the tube only days. Vintage amps also drive tubes harder now do to the higher line(outlet)voltage than we had years back.That might explain why good NOS tubes may be failing sooner than they should be.If a tube does flash in a amp,I wouldn't want to reuse it even if it wasn't at fault,assuming a part in the amp failed causing the tube to flash.

Thanks Newbee for pointing out about the yellow highlighting of the word "bad".... The yellow highlight is the nature of the beast apparently in the AA program when doing a search.
I entered "Bad EL34 Winged C tubes" so the word bad will be highlighted in all found posts.

http://db.audioasylum.com/cgi/search.mpl?forum=tubes&searchtext=bad+EL34+Winged+C+tubes+

And yes as you pointed out Jim does not say all EL34 Winged C tubes are bad.
Jim

Jea, perhaps I didn't express myself well. I'd NEVER stick a tube like that back into my amp.

As Hifi mentioned: most testers do not apply full operating voltages(B+) to the tube being tested. Tubes, under actual operating conditions, will occasionally either short, draw high screen current or open a connection internally. In the event of a short or high current draw; your circuitry may suffer some consequences. The only way to minimize the odds of that occuring is to burn in the tubes at full voltage and cull the weak ones prior to their use, as is Upscale's practice with their power tubes, ie:(http://www.upscaleaudio.com/rare/tpm.htm).

Rodman, funny you should mention Upscale because that’s where these tubes were purchased. I guess it’s the luck of the draw, and in my case, my draw was aces over sevens.

And Newbee, you have an interesting premise. I should have mentioned though that my amps are the Premier 12 XS, which are configured to use EL34’s. So I assume the bias circuit is designed around EL34’s, but I’m going to ask Conrad Johnson that exact question. It’s also interesting that the last time I was at Conrad Johnson, I bumped into Lew Johnson and asked him what he though might be going on. His first question was what type of speakers are you using. When I told him Quads (63’s), he commented that they (Conrad Johnson) had some previous problems with customers that used Quads and their amps. He said that the Quads, under certain circumstances might draw too much current. This all sounded a little strange to me (I was always told Quads and tubes were a good match) but I’m not an electrical engineer and he was talking a little over my head, so I may have misunderstood. Since then I’ve taken the Quads out of service, and I’m using dynamic speakers. But the problem has continued.

Thanks again for everyone’s comments. Any other thoughts would be very much appreciated