Seach for tubes - PL519 type - help

I'm checking for sources regarding the odd ball PL519 tube. I read on some website that PL519/PL509/40KG6 are similar tubes. Can anyone confirm this. Also, if anyone has information on where I can source these tubes (can be used & tested) I would be greatful. Ebay has RCA tubes but at $60 per tube that can be pricey given I need 16 tubes. Looking for cheaper alternatives if possible.

Paul, the tubes listed are all simular with the addition of the 40kg6a. There should be new Russian, hungarian and chinese tubes available for $25 a pop.
Did you try

Also, make sure you don't confuse these with EL 519 tubes
You can switch EL519 or EL509 with a mod to your gear, these tubes have a 6.3 heater voltage where as the PL509/ PL519 have a 40 volt heater. I have not done it but have heard of a few that have with very good results. And the Russians have plenty of these and alot cheaper.