Burned in Power Tubes? - 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 22nd August 2011, 10:48 PM   #1
diyAudio Member
 
Join Date: Aug 2011
Location: Florida
Default Burned in Power Tubes?

I was ready to buy a matched quad of JJ 6L6GC power tubes when I noticed a lot of dealers selling burned in JJ's for 5 dollars more. Seems like a good deal but I figured I'd email JJ to see what they thought about it. They said they already burn them in at the factory so there's no need to pay extra. I emailed some dealers to ask what their burn in is process but never received any replies. Any thoughts on this would be appreciated.
  Reply With Quote
Old 23rd August 2011, 01:20 AM   #2
diyAudio Member
 
HollowState's Avatar
 
Join Date: Aug 2006
Location: Taxland, New Jersey
Any maker worth their salt burns their tubes in. It's a necessary part of the manufacturing process. And I strongly suspect some do a better job then others. The better dealers will also process output tubes with a further burn in. Perhaps not to simply use it as an advertizing or sales advantage, but to assure themselves that the tubes they sell will hold up. Having to replace tubes that fail prematurely is a drag on business. But for either reason, it's a win-win situation.
__________________
"It is hard to imagine a more stupid or more dangerous way of making decisions than by putting those decisions in the hands of people who pay no price for being wrong." ~Thomas Sowell
  Reply With Quote
Old 23rd August 2011, 05:24 AM   #3
diyAudio Member
 
Join Date: Aug 2011
Location: Florida
Quote:
Originally Posted by HollowState View Post
Any maker worth their salt burns their tubes in. It's a necessary part of the manufacturing process. And I strongly suspect some do a better job then others. The better dealers will also process output tubes with a further burn in. Perhaps not to simply use it as an advertizing or sales advantage, but to assure themselves that the tubes they sell will hold up. Having to replace tubes that fail prematurely is a drag on business. But for either reason, it's a win-win situation.
Thanks HollowState, I think the dealer I'm buying them from is one of the good ones. I've always had good luck with JJ 12ax7's and from what I've read about the 6L6's they seem to have a good track record as of lately so, I think I'll put the 5 dollars towards some more 12ax7's.
  Reply With Quote
Old 23rd August 2011, 01:55 PM   #4
diyAudio Member
 
richwalters's Avatar
 
Join Date: Sep 2003
Location: Alps:Tube amp designs over 150W, SMPS guru.
I don't believe manufacturers "burn in" all tubes on a scale that demand requires........too much time sucked up on the soak rack and alot of electric....all overhead costs everyone is longing to cut back......so perhaps 1 out 10 and do the stat analysis.

When asking a vender about "burn in"; mention the approx operating conditions of tube(s)....also mention to "tap test". There is a proper impact gforce for this.. I found it's worth it esp B9A (microphony) and Int oct power types...where premature failure shows up pretty quickly.
Some will remember the earliest 1990 Chinese KT88 and other Sino clones produced some of the brilliant fireworks when tapped, many fell into the trap of putting these tubes directly into amps which were inbuilt within the loudspeaker cabinets, the resonance doing a perfect destruction of the tubes plus alot of circuit damage.

richy
  Reply With Quote
Old 23rd August 2011, 02:22 PM   #5
diyAudio Member
 
FullRangeMan's Avatar
 
Join Date: Aug 2009
Location: Brazil
FWIW, I read about the JJ quality control is non existent. Anyone have any additional opinion??
__________________
>Never go to a psychiatrist, adopt a cat or dog from the streets. On the streets pets live only two years average.
  Reply With Quote
Old 23rd August 2011, 04:31 PM   #6
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
I always purchase power tubes matched and burned in - the matching having occurred after 24hrs of burn in minimum. This process also IMHO reduces problems with infant mortality, and with reputable vendors usually results in tubes that remain reasonably well matched over their life time. (Not always the case)

The manufacturer being discussed has been much maligned lately for poor quality product wrt octal based power tubes and poor QC practices in general.. I'd be particularly leery purchasing power tubes of any brand without further burn in and testing by the seller. Most of the higher volume producers appear to have variable quality over time. I've had bad experiences with nearly every manufacturer currently making tubes. Caveat Emptor!

YMMV, and all above is just my opinion - speaking only for myself.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 23rd August 2011, 04:40 PM   #7
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Quote:
Originally Posted by FullRangeMan View Post
FWIW, I read about the JJ quality control is non existent. Anyone have any additional opinion??
I bought a matched quad of JJ 6CA7's in 2010, they are fine. Great, since the alternate source pays taxes to an oligarchy. Since the boxes were marked with a number, perhaps the manufacturer did the matching.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 23rd August 2011 at 04:45 PM.
  Reply With Quote
Old 23rd August 2011, 10:05 PM   #8
diyAudio Member
 
Join Date: Aug 2011
Location: Florida
I suppose another 5 dollars is worth it as long as the dealer burns them in further. I didn't find out how long a period JJ burns them in but they claim they match them for GM and Plate current. I have a set of 8 JJ EL84's in my Peavey 50/50 for over a year and they are ok and sound great. I'll have to contact the dealer and see how much longer they burn them in for.
  Reply With Quote
Old 23rd August 2011, 10:35 PM   #9
diyAudio Member
 
Join Date: Dec 2006
Location: Southwest Chicago Suburbs
Quote:
Originally Posted by FullRangeMan View Post
FWIW, I read about the JJ quality control is non existent. Anyone have any additional opinion??
I am VERY reluctant to deal with JJ tubes at all. There are a few that are okay - EL84, the 12DW7/ECC832, and a few others - but the octal power and rectifier tubes I won't even stock. Too many rejects, I simply can't afford to handle tubes with such high reject rates.

Regarding vendors burning in tubes - infant mortality is the #1 problem with tubes, so any rational steps taken to minimize it are worth doing. I don't charge any extra, but that's me - what others do is up to them.

I think Kevin's post above is pretty much right on target.
  Reply With Quote
Old 24th August 2011, 05:53 AM   #10
diyAudio Member
 
Join Date: Aug 2011
Location: Florida
Quote:
Originally Posted by Jim McShane View Post
I am VERY reluctant to deal with JJ tubes at all. There are a few that are okay - EL84, the 12DW7/ECC832, and a few others - but the octal power and rectifier tubes I won't even stock. Too many rejects, I simply can't afford to handle tubes with such high reject rates.

Regarding vendors burning in tubes - infant mortality is the #1 problem with tubes, so any rational steps taken to minimize it are worth doing. I don't charge any extra, but that's me - what others do is up to them.

I think Kevin's post above is pretty much right on target.
Perhaps some TAD 6L6GC-STR's are the way to go. I read a review stating the similarity to the JJ's tone but one step better and worth the extra cost. I just want something with nice lows without breaking the bank. I tried Winged C's in the amp and they sounded thin. I thought the JJ's were the way to go but maybe the TAD's would be better.
  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
NAD 502+512+514 - Burned Transistor from Focus Power Buffer Output Stage (pos. Half) tiefbassuebertr Digital Source 0 28th July 2011 04:40 PM
@#$^!! Burned out power amp Dave Jones Solid State 1 14th January 2011 09:40 PM
Burned out power tube fauxpas Tubes / Valves 14 26th January 2008 07:32 PM
Power Tubes s2kov Tubes / Valves 6 18th November 2004 09:23 AM
I burned my Aleph 3! Please help! Jesse Pass Labs 25 26th October 2003 01:56 PM


New To Site? Need Help?

All times are GMT. The time now is 06:38 PM.


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