I can second TC Tubes for testing services. I had them test a pile of Winged C 6550's and Ei KT-90's last year (nice that they are in the same metro area!). Tyler was very informative in evaluating the results, and his Amplitrex tester is first class.
Selling Tubes.
Over the years I’ve accumulated about 10-15 vintage tubes I no longer need. I’m wondering if anyone here has found a reliable vendor that will buy excess tubes. I don’t have a tube tester and can’t fairly describe the condition of the tubes, so I can’t seller them here. The alternative would be to have them tested and then sell them with the test results in hand, but I haven’t seen a tube testing service. Thanks.