Detached getter? - 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 24th March 2009, 04:26 AM   #1
rknize is offline rknize  United States
diyAudio Member
 
rknize's Avatar
 
Join Date: Feb 2009
Location: Chicagoland
Send a message via AIM to rknize Send a message via Yahoo to rknize
Default Detached getter?

I've never seen anything quite like this. It's an eBay tube. The description was sketchy but they were supposedly tested. Looking carefully at the original eBay ad, I can see the missing getter in the pic. There are bits of getter floating around in there, so I suspect this tube is not safe to use.

It almost looks like some kind of arcing happened, because the getter is blown onto the glass base where the support wires all come together. Strange.

Russ
Attached Images
File Type: jpg 45-deteached-getter.jpg (37.0 KB, 266 views)
  Reply With Quote
Old 24th March 2009, 09:05 AM   #2
diyAudio Member
 
Geek's Avatar
 
Join Date: Sep 2004
How hot he get that thing
  Reply With Quote
Old 24th March 2009, 01:17 PM   #3
ktuuri is offline ktuuri  Canada
diyAudio Member
 
Join Date: Nov 2007
I have had the rectangular part of the getter fall off its support rod and land in the bottom, everything works fine, but yours looks like it exploded.
  Reply With Quote
Old 24th March 2009, 06:29 PM   #4
diyAudio Member
 
HollowState's Avatar
 
Join Date: Aug 2006
Location: Taxland, New Jersey
I cannot help thinking that at some time someone tried to reflash the getter under an RF induction heater to improve and restore the film coating inside the glass. Bringing the tube's getter into close proximity to the work coil of a relatively small bench top heater (sometimes called a bombarder) is the method used. But often this fails to produce good results because once originally heated and cooled, the getter's chemistry is depleted. Too much power and/or time spent heating produces the results you see if the getter's closed loop didn't open first. Trying to restore used tubes was not that uncommon years ago by some surplus dealers.

I would imagine if you used the tube vertically and kept the loose pieces at the bottom of the envelope, it should work ok.
__________________
"I regard the brain as a computer which will stop working when it's components fail. There is no heaven or afterlife for broken down computers. That is a fairy story for people afraid of the dark." ~Stephen Hawking
  Reply With Quote
Old 24th March 2009, 06:36 PM   #5
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
I have an old tube with some of the getter material floating loose inside it. It still works, and coincidentally it is a 45 that I got on Ebay. I bought 3 used 45 tubes for $12 because they were sold as "weak" and the loose getter material on one tube was mentioned in the text. Yes it was several years ago.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 24th March 2009, 07:25 PM   #6
rknize is offline rknize  United States
diyAudio Member
 
rknize's Avatar
 
Join Date: Feb 2009
Location: Chicagoland
Send a message via AIM to rknize Send a message via Yahoo to rknize
Thanks. Trying to reflash the getter makes some sense based on the shape of the missing area and the way the getter got blasted onto bottom of the tube structure. The other tube's getter looks funny too and with the reflashing idea it may make sense. I can't really capture a picture of it, but it looks as if there are two layers of getter with a more faded larger area and a more opaque area at the bottom. Definitely not your typical worn-getter look.

Speaking of weird getters. I have another eBay 45 with a getter that looks fine (very shiny with little fading at the edges) except it is riddled with pin holes. Not unlike what you would see with car paint sprayed on a poorly prepped surface (fisheyes). The tube tests strong. I suspect it happened at manufacturing.

I don't own a tube tester, but with the adjustable fixed bias of the Tubelab SE I can measure delta Ia and delta Vg to calculate transconductance to compare with the operating points. How would I check for gas? Look for white noise on a scope? My ear against the left-versus-right tweeter?
  Reply With Quote
Old 25th March 2009, 06:32 AM   #7
rknize is offline rknize  United States
diyAudio Member
 
rknize's Avatar
 
Join Date: Feb 2009
Location: Chicagoland
Send a message via AIM to rknize Send a message via Yahoo to rknize
I tapped on the tube a bunch to try to coax the flakes to the bottom, but the tube just crackled loudly and started drawing a lot of current. The other tube I mentioned about with the weird double-getter also has a funky kink in one of the filament courses. They are from the same lot. Having a filament touch the grid would probably make the MOSFET mad, so I will probably trash this tube too. It biased OK, though.

Caveat emptor eBay ID "mook44".
  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
What the heck does a getter do ? bereanbill Tubes / Valves 4 17th May 2009 08:51 PM
KT66 loosing its getter ixe13 Tubes / Valves 2 27th February 2008 02:33 AM
6D22S Getter Question Ardee Tubes / Valves 5 27th September 2006 10:35 AM
shiva spider detached!!! hassandaman83 Subwoofers 28 2nd January 2005 05:45 PM
Plate color and getter Jeffy74 Tubes / Valves 9 24th February 2004 12:14 AM


New To Site? Need Help?

All times are GMT. The time now is 10:11 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