Does any one know of a source for German tubes? I am looking for a UM-4 which is a tuning eye with a 35 volt heater. It is for a 1953 INGELEN model 650 short wave radio. No luck with Antique Electronic Supply. Thanks Paul A. Litwinovich Chief Engineer/ Webmaster WSHU AM&FM, WSUF-FM N1MUC "RF IS GOOD FOR YOU"