Tube tester?

Agree with carlsbad…Unless you are buying and selling tubes or are bored and want to dig into tubes and tinker with testers just locate a repair shop that tests tubes or testing service like the one on the link below. I was considering buying one until I researched it and talked to experts. The affordable testers in good working order only tell you if a tube is good meeting the standard. If you buy a one that has the capability to measure GM, match etc. ,which are expensive, they have to maintained and calibrated regularly.
Tube testing service example: https://www.western-glow.com/vaccum-tube-testing-matching/

@carlsbad 

+1

I am not in the geek camp. I have all tube gear. My equipment has tube time counters. Even if they didn’t it isn’t that hard to generally estimate the tube time. I have about 40 tubes in my system. I have swapped 3 tubes in the last 3,000 hours of play… they are recommended to be replaces every 2,000 hours.

I just buy tube sets either from the equipment manufacturer or Upscale or the Tube Company. I keep an extra set for each unit. If you get a whistle or strange effect. Swap to new tube set a couple at a time to ID bad tube. This has only happened to me twice in ten years. Really simple.

I'll add that you can get a lot of info about a tube from your amp, especially is it has manual bias adjust.  Not everything, but a lot.

you have to understand the electronics though.

Jerry

Like a broken record, I keep on saying anyone with tube equipment should buy their own tube tester.

I had a nice 666 Eico tester. I didn't use it much. I buy new production tubes from very reliable sources and I have only had one issue with a noisy preamp tube. The tube tester doesn't insure quiet tubes because it's the function of the preamp circuit that determines that. Listening is the only way sometimes. I've also blown power tubes, that is spectacular and no measurements are needed, the whole tube bank gets replaced at that point. Bottom line...I have no tester and really not missing it.  

"95/91 or 46/41" If these numbers are written on the side of a tube with a Sharpie they are the test results of a 2 section tube. Unfortunately they are meaningless unless the tube tester is known along with the results chart. Now generally 95/91 is generally a good reading, however 46/41 is not. Take this with a grain of salt as the tube tester is unknown. Always buy tubes, especially ones that need matching from a reputable vender. A Google search will give you a start.