Genelex gold lion el84 reissue - ARCING

adamus · 4th May 2009, 04:17 PM

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?

Aloha,

Poinz
AudioTropic

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.

Aloha,

Poinz
AudioTropic

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...

4th May 2009, 04:17 PM	#1
adamus diyAudio Member Join Date: Apr 2008	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?

4th May 2009, 05:56 PM	#7
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Check shortage of the filament to cathode. __________________ If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.

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4th May 2009, 05:23 PM	#2
Poindexter diyAudio Member Join Date: Oct 2004 Location: Maui, Hawai'i, USA	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? Aloha, Poinz AudioTropic

4th May 2009, 05:28 PM	#3
adamus diyAudio Member Join Date: Apr 2008	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)

4th May 2009, 05:34 PM	#4
adamus diyAudio Member Join Date: Apr 2008	once arced... is that it for the tube?

4th May 2009, 05:35 PM	#5
Poindexter diyAudio Member Join Date: Oct 2004 Location: Maui, Hawai'i, USA	Not good. Have you talked to your vendor?  That's a replaceable defect. Aloha, Poinz AudioTropic

4th May 2009, 05:54 PM	#6
adamus diyAudio Member Join Date: Apr 2008	I'll have a chat with them tomorrow. Cheers for the advice

4th May 2009, 06:07 PM	#8
adamus diyAudio Member Join Date: Apr 2008	no short, just a very brightly glowing tube, ther all seem fine. IT took about 15 mins for the intitial arc.

4th May 2009, 07:26 PM	#9
DonA diyAudio Member Join Date: Oct 2007 Location: Flatlands of Central California	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...