Tube life question - 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 29th March 2003, 01:53 AM   #1
diyAudio Member
 
Join Date: Jan 2002
Location: Tyrone Ga. U.S.A.
Default Tube life question

I am thinking of building a OTL amp. My question is how long
can I expect a 6as7ga to live if asked to handel 100 ma at 100v.
Or how much longer would it live if asked to only handel 70 ma at
100v?

Thanks

bob12345678
  Reply With Quote
Old 29th March 2003, 02:07 AM   #2
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default I AM BAD.

Hi,

Does starving yourself to death help?
__________________
Frank
  Reply With Quote
Old 29th March 2003, 02:36 AM   #3
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Try one at 300mA, 200V. After that one goes, try stepping down the voltage and/or current a little and try again... After that one goes......



Tim
  Reply With Quote
Old 29th March 2003, 03:47 AM   #4
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Steve Bench has a report on his site where he's tallied lots of data and related it to the type of filament and their power, versus the cathode current. Not definitive, but gives an idea.

http://members.aol.com/sbench/heater.html
  Reply With Quote
Old 29th March 2003, 04:43 AM   #5
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Someone here should conduct a test. Grab a box of say, 12AU7s, 6V6s, 6L6s, a type of sweep tube, and some 6080s or 6AS7s and see how long they last for each rating.
Unfortunately, this could take a *long* time to get the data.

BTW, I heard that unipotential coated cathodes can do like, 200mA/W at saturation. So in theory, a 6CD6 could pull 3 amperes of cathode current! Of course, screen and grid voltages would have to be through the roof...

Tim
  Reply With Quote
Old 29th March 2003, 06:20 AM   #6
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Default Valves last forever!

Provided that you stay within all the manufacturer's ratings, valves last forever. I say this because DIY amplifiers are generally made obsolete by their owner/builder thinking up a new idea long before the valves wear out.
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 30th March 2003, 12:48 AM   #7
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default MUCH UNDERRATED...

Hi,

Quote:
Provided that you stay within all the manufacturer's ratings, valves last forever.
Proviso: you take the low side, not the hot side of specs.

For instance: run a 12.6 heater at 12 V and just make sure it can draw it's required current which I feel is more important than the voltage rating, never overdo the ratings or you'll see transonductance figures of the tube vannish within a few minutes.

Cheers,

/Forever.
__________________
Frank
  Reply With Quote
Old 31st March 2003, 10:23 AM   #8
SHiFTY is offline SHiFTY  New Zealand
diyAudio Member
 
SHiFTY's Avatar
 
Join Date: Jul 2002
Location: New Zealand
Quote:
Provided that you stay within all the manufacturer's ratings, valves last forever. I say this because DIY amplifiers are generally made obsolete by their owner/builder thinking up a new idea long before the valves wear out.
Are you saying we're ever so slightly insane?
  Reply With Quote
Old 31st March 2003, 02:10 PM   #9
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Default The men in their CLEAN white coats...

Quote:
Originally posted by ShiFtY
Are you saying we're ever so slightly insane?
Never. I am sure that we all operate a policy of constant improvement on our products driven by a vigourous research initiative, supported by a vigilant purchasing department, and backed by distaff-led industrial design.

(Translation: I've thought of this great new idea for a valve I couldn't resist on eBay, and I've promised to make it look nicer this time.)
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 31st March 2003, 02:17 PM   #10
robbie is offline robbie  United Kingdom
diyAudio Member
 
robbie's Avatar
 
Join Date: Mar 2003
Location: south coast
Default i so know

where you are coming from..

think its a male 'thang'
  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
tube life bonsai171 Tubes / Valves 20 28th April 2010 09:21 PM
Used Tube Amps, second life.. planet10 Tubes / Valves 24 29th January 2009 04:43 PM
Maximising Tube Life jkeny Tubes / Valves 44 13th September 2008 02:37 AM
best long life for my tube jeapel Tubes / Valves 2 4th May 2005 10:22 PM
Tube Life Glowin Plates Tubes / Valves 14 6th October 2004 06:01 PM


New To Site? Need Help?

All times are GMT. The time now is 11:41 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