2. analog
  3. 166328-1009

Does tube testers tell how much life is left for tubes?

Let's say that you have new tubes, very old tubes that are almost to die, and something in the middle.
What kinds of reading do you expect from these three kinds?
Can you usually tell the life of tubes from tube testers?
How about the color? Do those three kinds of tubes have different colors when they were turned on?
I would like to know when to change tubes before it gets too late.
Some says if it sounds good, don't bother to change. 
Some brands of power/pre amps consume more on tubes than other brands and their life seems varies brand by brand. 
128x128ihcho

Showing 2 responses by jjss49

jjss49's avatar
Ag insider logo xs@2x
jjss49
6,612 posts
 
short answer is even the best tube testers measure the present degree of mutual transconductance of a test subject tube - it is a decent proxy for tube strength/freshness but it is a poor proxy for durability as a function of time

if you want to educate yourself more...

http://www.alltubetesters.com/articles/tester_guide.htm

http://www.jacmusic.com/Tube-testers/

https://shop.ehx.com/vacuum-tube-faq/ - see section on tube testing
jjss49's avatar
Ag insider logo xs@2x
jjss49
6,612 posts
 
different tubes age in different ways

6dj8 6922 types, in my experience, get noisy with tube ’rush’ or hiss, and microphonic long before they quit entirely - not sure why this happens in the physics occurring inside the tube as time passes -- these will test fine on the tester for gm but then plug em into the linestage or phono stage and they are unlistenable

depending on the application, that change defines their effective ’use-ability’

other tubes may age differently... typical power tubes usually get dull in sound (lose treble detail imaging etc etc) as they get into last 30-40% of their lives


More to discover