Genelex gold lion el84 reissue - ARCING - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th May 2009, 07:30 PM   #11
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
bias is fine, its 36ma through a CSS, if it goes then it just runs away
  Reply With Quote
Old 12th May 2009, 12:00 PM   #12
diyAudio Member
 
Join Date: Mar 2009
Send a message via MSN to MBMerlot
Default Gold Lion EL84's

I've had the same problem with these tubes. It seems that the cathode - grid - to plate alignment is off on 3 of 4 that I have. I guess I'll try the Mullard reissue's.
  Reply With Quote
Old 12th May 2009, 01:03 PM   #13
diyAudio Member
 
Join Date: Dec 2006
Location: Southwest Chicago Suburbs
Default Re: Gold Lion EL84's

Quote:
Originally posted by MBMerlot
I've had the same problem with these tubes. It seems that the cathode - grid - to plate alignment is off on 3 of 4 that I have. I guess I'll try the Mullard reissue's.
What are you saying - you've had arcing or "bright glowing" tubes? I'd be interested to know.

Just FWIW, I've had about 100 pieces pass through here with just 1 dud. It sounds like there may be another problem beside the tube in play here.

A word of warning - the "factory match" is horrible! I've had "factory matched" quads with 11 ma difference in plate current. And a poorly matched quad almost invariably has one or more "current hogs". These tubes will often red plate, etc., but it's not the tubes - it's the poor matching.

With 3 of four acting up I'd guess either you have a poorly matched quad or you have tubes that were severely shocked in transit.
  Reply With Quote
Old 12th May 2009, 04:57 PM   #14
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
mine flashed, and one had a horribly bright hotspot in the middle of the heater.

Just had a call from the supplier, they have tested it an confirmed its arcing when approachign 300v, so they are replacing it. Good service.
  Reply With Quote
Old 12th May 2009, 06:21 PM   #15
diyAudio Member
 
Join Date: Mar 2009
Send a message via MSN to MBMerlot
Jim,

The ones that I have are in a Dr. Z Prescription Extra Strength Amp.

I'm experiencing the exact same physical symptoms as yours. From my experience. This occurs when the distance from cathode to plate is off alignment.

Probably going to call EH and tell them about it. Have you had 100 and only 1 out of that bunch did that to you? I would like to know, because I do plan on contacting them about it.

PS. Making tubes is an art form. They just haven't reached the pinnacle.
  Reply With Quote
Old 12th May 2009, 09:43 PM   #16
diyAudio Member
 
Join Date: Dec 2006
Location: Southwest Chicago Suburbs
Yes, just 1 failure out of about 100 tubes.

But I can't make out what happened to yours, since I didn't describe the physical symptoms (there were none, it just died - bad connection internally??). Are you saying the 3 tubes arced or that they had hot spots on the plate?
  Reply With Quote
Old 12th May 2009, 11:49 PM   #17
diyAudio Member
 
Join Date: Mar 2009
Send a message via MSN to MBMerlot
Screen grid meltdown, etc.. JJ's work fine in the amp, Mullards work fine in the amp. It's not the amp.

Yes, the plates are glowing red from electron bombardment. Like I said before, typical of a misalignment inside the tube.
  Reply With Quote
Old 13th May 2009, 02:16 AM   #18
diyAudio Member
 
Join Date: Dec 2006
Location: Southwest Chicago Suburbs
It may well have been the tubes - but according to what I can find the bias on the amp is not adjustable. Is it cathode biased?

Were you able to confirm the bias was in the normal & typical 30 ma. area? Forgive me if I seem to be cross-examining you, I don't mean for it to sound that way. But just because a set of JJ or Mullard worked fine does not narrow it down to the Genalex tubes themselves when they were acting up. If the bias is not adjustable and is not cathode bias, a set of "hot" Genalex could act just the way you described and not be defective. They could have been just passing too much current and the screens and/or plates overheated. Sets of relatively cool JJs or Mullards wouldn't necessarily act up the same way.

I've seen that exact scenario many times on many different amps.

If you have any comments please share them, and thanks again!
  Reply With Quote
Old 14th May 2009, 05:31 PM   #19
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
bleugh.....

got my replacement tubes..... and one is exhibiting the indredibly bright heater again. instead of the normal orange glow its really whitish yellow in the section you can see through the hole in the plate.

its not arced as yet.....

the quality control on these seems really bad. for instance, one of the tubes as about 2mm of heater filament exposed at the top. The other has barely anything, not great on tolerance control.

I hold out little hope for the replacement tube with the hotspot on the heater.

volatge measures a perfect 6.3v ac.
  Reply With Quote
Old 14th May 2009, 06:31 PM   #20
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
OMG..... i really hope this is a mistake on behalf of the supplier.

whenever i send anything back component or toolwise i alway put a black spot on it with a sharpie marker. mainly because i have a bit of a trust issue.

Pulled the valve with the bright spot in it..... and there is my black spot. All this after i was promised they were replaced. grrrrr

I hope to god its a mistake, otherwise name and shame is coming.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SimplSE Gold Lion KT77 tube set nvrgdenuf Swap Meet 0 2nd August 2009 09:47 PM
Gold Lion KT88 (lightly used, matched pair) n_maher Swap Meet 1 26th May 2009 06:42 PM
Genelex Gold Lion KT88s (reissue version) (matched quad, lightly used) n_maher Swap Meet 8 10th September 2008 06:01 PM
Genalex Gold Lion KT77 Tam Shaun Tubes / Valves 24 22nd August 2008 02:05 AM
Gold Lion KT88 Reissues marshall1988 Tubes / Valves 1 29th November 2006 07:18 PM


New To Site? Need Help?

All times are GMT. The time now is 04:42 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2