KT-150 Tubes- Push Farther or Replace?

After a little reading and putting some more thought into this I’m realizing the reality of this (at least my reality!). As @mulveling first suggested- my system uses 4 different makes of tubes. A gang of 8 KT150 and 11 6H30’s. My DAC uses a couple of the smaller 12AT7’s (which seem to go on forever). With this commonality across the equipment I don’t really see myself critiquing individual tubes as opposed to wholesale changeouts when approaching the recommended end of life hours.

It also seems (pointed out by @mulveling ​​​​@invalid) that a tester really isn’t going to buy me much when it comes to the KT150 in particular due to the voltages required for an accurate test/comparison. The test stations equipped to deal with these are of considerable expense (more than a new set of tubes) and in reality I would just pull and replace.

I liked the thought of having one though- kind of nostalgic but (at least in my case) it doesn’t seem like I would put one to much use. As always- I appreciate the advise given!

You advice is very good, IF people will spend the money for ’real’ testers. I read very little about member’s tube tester results here. My friends don’t have them, they rely on me.

Can you give a short list of testers, perhaps a few to look for, and pick a current eBay listing or two of better ones.

Some newer tube amps have visible and external bias adjusters, many do not, sadly my early Cayin A88T adjusters are internal. Again, I suspect only those with external adjusters use them.

I got the info to adjust mine internally, including advice here, then chickened out and took it to Steve at VAS. When I was younger, I’d have been in there with metal! Joking, I would have left it unplugged a few days, left it unplugged, deoxit, twist back and forth, and left them physically mid-point (i.e. no meter, just guess): ’good enough, close it up!

@elliottbnewcombjr-

Hello! I can't speak to which testers would be considered real or better than others- I just did some quick reading on the products suggested by others. Those were the Maxipreamp, Amplitrex and Space-Tech Labs. It seems there are many out there in the used market that ranged from $750 on up and new units going upwards of $1.5K (or more). I have no past experience with these as my amplifiers bias adjustment is performed while reading the meters on front of the amp. 

BIAS Meter.

OK, paraphrasing someone else:

a. setting bias is like setting the idle to a car's engine.

b. It's about when they are doing nothing, ready, but not about when they are busy amplifying, correct?

Bias effects tubes at their idle stage. You run them within a range, cool to hot, yielding more or less life. You can see/feel if they are running hot.

Bias can effect the output sound to a degree.

If amp allows use of different tube types, recommended to adjust bias  

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Questions (what does bias tell us about tube strength/matching strength?)

1. using bias meter, adjusting 'idle' of each tube, matching their bias:

does it indicate tube strength?

tube strength matching?

2. not holding bias is definitely a bad tube?

Can you find a 'strong, ok, weak, bad' tube strength via Bias?

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What I'm driving at is: my little tube tester has always told me about tube strength, and relative to each other strength, found any weak or bad tube, found any short, since my wife surprised me with it as a birthday present back in 1972, 50 years of answers that were better than flying blind.