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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
ihcho's avatar
ihcho OP
609 posts
 
I've just came up with an idea how to deal with when to change tubes. Always have spare tube sets ready. Then, if suspicious, change the tubes. If it sounds much better after the change, keep the change. If the difference is subtle, put the old tubes back and keep listening until feeling suspicious again.
petg60
1,486 posts
 
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
True.
pindac's avatar
pindac
2,361 posts
 
The Following is a recent report I received on a Early 60's produced Valve.
It covers the Anode and Mutual Conductance.
As can be seen each Valve has a very good reading compafrd to a New Factory Spec Valve , whicch is the 100% readings.
What is not shown is if here is a Cathode  / Heater Leakage that if present can impact on a Valves Function for the worse.
 
  Tested on my uTracer @ 90V -1V

100% is 15mA Ia , 12.5mA/V gm
Valve 1

Section 1 – 17.16mA / 12.37mA/V
Section 2 – 16.13mA / 12.39mA/V

Valve 2

Section 1 – 17.39mA / 11.84mA/V
Section 2 – 18.92mA / 13.16mA/V
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