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adamus 4th May 2009 04:17 PM

Genelex gold lion el84 reissue - ARCING
I bought some genelx n709 (el84) reissues.

I have one that is arcing, so i quickly turned the amp off. Its heater is much brighter than the other 3, so i assume somethign is wrong.

My only slight concern is that i am running them at 330v B+, so you think it could be out of spec?

Poindexter 4th May 2009 05:23 PM

First, EL84 is a 300V tube, so yes; you are out of rating.  Second, if the heater of that tube is glowing a lot brighter, yes; you have a problem there.  Is there any way the heater voltage could be high on that one tube?



adamus 4th May 2009 05:28 PM

heater voltage is perfect, 6.3v bang on, but its a lot brighter than the others - it has a real hotspot right in the centre (glowing yellow / whitish yellow)

adamus 4th May 2009 05:34 PM

once arced... is that it for the tube?

Poindexter 4th May 2009 05:35 PM

Not good. Have you talked to your vendor?  That's a replaceable defect.



adamus 4th May 2009 05:54 PM

I'll have a chat with them tomorrow.

Cheers for the advice

Wavebourn 4th May 2009 05:56 PM

Check shortage of the filament to cathode.

adamus 4th May 2009 06:07 PM

no short, just a very brightly glowing tube, ther all seem fine.

IT took about 15 mins for the intitial arc.

DonA 4th May 2009 07:26 PM

If you have a tube that was arcing pretty much as soon as the amplifier warmed up, it appears that tube is bad right out of the box. Since you say the heater has an unusual appearance, this is more evidence that the fault lies with the new tube.

I assume your bias adjustments are OK (if you have any)... but try reversing the positions of these 2 new tubes, re-bias them (if you can), and IF the problem stays with the tube, it's bad - period. I assume they are guaranteed and if so, exchange it for a new one ASAP.

Hope that helps...

DonA 4th May 2009 07:26 PM

Oh, and your 330v B+ is fine...

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