brown crud?

Bandersnatch · 19th October 2008, 12:19 PM

hey-Hey!!!,
What is that brown stuff that seems to condense out on the inside of power tube envelopes( TV sweeps in particular )?
cheers,
Douglas

kevinkr · 19th October 2008, 05:32 PM

Hi Doug,
I've always thought this was part of the filament material boiling off and being deposited on the glass. You see the same thing in certain types of tungsten projector lamps amongst other things..

wrenchone · 21st October 2008, 07:13 AM

I'm looking now at a pair of what look to be grossly abused 6JE6s I got on Fleabay for cheap - now I see why. The getters look a bit thin and discolored, and brown staining is clustered around where the mica meets the glass - top and bottom, and where the glass may have been a little cooler. I'm thinking it may be redeposited getter material, as the getters look thin and bulls-eyeish (and brown). Where the plates come close to the glass, the discoloration is missing. Those plates must have been fearsomely hot.

Geek · 21st October 2008, 09:44 AM

Age? Hard use?

They always seem fine on the tester though. Some tested higher umhos than NOS.

*shrug*

Cheers!

19th October 2008, 12:19 PM	#1
Bandersnatch diyAudio Member Join Date: Jul 2003 Location: Ann Arbor, MI	brown crud? hey-Hey!!!, What is that brown stuff that seems to condense out on the inside of power tube envelopes( TV sweeps in particular )? cheers, Douglas __________________ the Tnuctipun will return

19th October 2008, 05:32 PM	#2
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	Hi Doug, I've always thought this was part of the filament material boiling off and being deposited on the glass. You see the same thing in certain types of tungsten projector lamps amongst other things.. __________________ www.kta-hifi.net

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Dysan Brown dye CD's????	Zero Cool	Everything Else	0	21st June 2009 01:17 AM
Burr Brown Pcm 65 dac	rickpt	Digital Source	1	12th June 2006 06:33 PM
brown out may have fried my amp	ejn327	Subwoofers	1	11th December 2005 09:28 AM
Brown Dog postage	5th element	Parts	0	23rd June 2004 05:19 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

21st October 2008, 07:13 AM	#3
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	I'm looking now at a pair of what look to be grossly abused 6JE6s I got on Fleabay for cheap - now I see why. The getters look a bit thin and discolored, and brown staining is clustered around where the mica meets the glass - top and bottom, and where the glass may have been a little cooler. I'm thinking it may be redeposited getter material, as the getters look thin and bulls-eyeish (and brown). Where the plates come close to the glass, the discoloration is missing. Those plates must have been fearsomely hot.

21st October 2008, 09:44 AM	#4
Geek diyAudio Member Join Date: Sep 2004	Age? Hard use? They always seem fine on the tester though. Some tested higher umhos than NOS. shrug Cheers!

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)