This Osram KT66 tube tests:

60/32

on my TV-7D tester (calibrated annually). Brand new tubes should test 49/32 or higher. Tested for shorts, emission, gas and noise.

I also tested this in my Hickok 539c at 8500 mhos with a minimum good value of 3150 mhos.

This is a very early KT66, dated AM, or December of 1945. The base is tight. It comes in its original packaging!

Branded OSRAM; this is the same construction as the Marconi, Emitron, GEC, Genalex and other made in Britain KT-66 tubes. This is very similar to a 7581A and CV1075 tube. It often works as a substitute for a 6L6. Check that this works with your equipment if you plan to use it as a substitute, and or message me what you intend to use it for. I’m happy to help you sort compatibility before you buy it.

This tube is in excellent physical shape. See the pictures for condition and ask questions. I do not accept returns unless the items are not as described.

I’m in the process of listing thousands of tubes. If you want something in particular message me to see if I have it. Thanks!