HEATER-WARM-UP TIME IS DEFINED AS THE TIME REQUIRED FOR THE VOLTAGE ACROSS THE HE ATER TO REACH. 80% OF ITS RATED VOLTAGE AFTER APPLYING 4 TIMES RATED HEATER ...
Tube 13DR7 or Röhre 13DR7 ID5457, Double Triode, Noval, 9 pin miniature (USA pico-9) B9A and shown. Radio tubes are valves.
13DR7 dual triode tube, new old stock, boxed. Tested working and guaranteed 30 days. Substitutes: 13FD7, 13FR7; EIA Base: 9HF ...