best tube tester is the hiccock 539c but its not cheap a nice sencore can be had for under 200 service is near impossible get one that works
Tube Tester
Thinking of buying a used tube-tester. Can you tell me what to look for? Explain some of the terms, e.g. mutual, conductance, emission, etc. Recommendations (Eico, Sencore, Mercury, etc.), model number and why? All I need is a basic type, but I like to know more. Thanks!