I have been moonlighting over at Antique Radio Forums. I have been interested in testing power tubes. I've been using a lot of JJ tubes and bought a bunch that were supposedly matched from tube depot only to have a local guy near here with a old tester to tell me that they were not matched. That got me thinking. We Valve Amp people are at the mercy of trusting people we buy from. Who is really to say if that NOS GE 7027A is any good. Tube Depot JJ7027A's that I bought came with a transductance number - but no indication of how it was measured. Considering we pay so much for these increasingly rare tubes, it would be good to have some trust in numbers and not be at the mercy of the seller. Most tube tester rigs are subject to a lot of error and each model is designed differently and tells you different things. Just bringing a tube to someone and having them stick it in a tester really doesn't guarantee anything. So I am designing a tube tester that is built from lab equipment and will take look at all my power tubes. At this point, I am only designing it to test octal power tubes and compare the measurements to RCA data sheets. Heck, maybe I will start a side business to scientifically certify tubes?