An SX-25 came to me with a VT-269 plugged into a socket where a 6SK7 should be. I can find references to the VT-269 and a cross to a WE-717A, but I have no data for testing nor do I have a base diagram. Does anyone know if it is, in fact, compatible with a 6SK7? One source suggested a 6SJ7 "with wiring changes"! Bill VE3NH