I just picked up a push-pull 300B amp that came with a set of four of these. 3 of the 4 test nicely and are a close match for Gm, but the fourth looks like a used replacement (has burn marks around the top and no printing, whereas the other three are clean and have Valve Art printed on the glass). It is reasonably close on Gm, but I would rather have it laying around as an emergency spare.
I would like to see if I can find a nice testing and similar appearance fourth (slightly used is actually preferable). Nice Gm test is enough - the amp has some level of individual bias adjust so I can live with reasonable current draw variation.
I have a lot of tubes laying around, so a trade would be preferable (partial or full) but I can also possibly buy outright (depending on price).
You can email directly at baileyler@comcast.net.
