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NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre
NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre

NOS? Siemens & Halske BF Test GOOD 20s Vacuum Triode Radio Audio Tube Post-Röhre

$ 844.8

  • Brand: Siemens
  • Country/Region of Manufacture: Germany
  • Custom Bundle: No
  • MPN: AV=0N
  • Model: BF
  • Modified Item: No
  • Type: Power Tubes

Description

NOS? SIEMENS & HALSKE BF Price is for 1 either NOS or close to such tube. This is vintage vacuum triode valve made somewhere in the early 1920s by Siemens & Halske in Berlin or Munich, Germany. So-called "post-rohre". According to the book "Saga of the Vacuum Tube": The BF tube was introduced in 1920 and was used until 1925 by the German Reichspost in all amplifiers. This tube was made by Siemens & Halske. The BF tube had a tungsten filament which required 1.1 amperes at 3.5 volts. The anode voltage was 220 volts, the amplification factor was about 14, and anode resistance was 25,000 to 30,000 ohms.4 The mutual conductance was about 500 micromhos. The useful life was 2500 hours. EXTREMELY RARE! NEVER SEEN SUCH LISTED ON EBAY! Shipping will be Airmail registered with tracing number. Other shipping methods available on request.