SIEMENS EBF 89 = 6 DC 8 Duodiode-Variable-mu Pentode Vacuum Tube, Noval Base, 9 Pins

For radio technicians and vintage audio enthusiasts restoring classic receivers, the SIEMENS EBF 89 (equivalent to 6DC8) is a duodiode-variable-mu pentode vacuum tube. It combines a diode section for detection and AGC with a variable-mu pentode for IF amplification, making it a key component in many tube-based radios and amplifiers.

Key specifications

• Tube type: Duodiode-variable-mu pentode
• Equivalent tube: 6DC8
• Base: Noval (B9A), 9 pins
• Heater voltage: 6.3 V
• Heater current: 0.3 A
• Pentode anode voltage: 250 V (typical)
• Pentode screen grid voltage: 100 V (typical)
• Pentode transconductance: 3.8 mA/V (typical at Vg1 = -2 V)
• Pentode anode current: 7.5 mA (typical at Vg1 = -2 V)
• Diode max peak inverse voltage: 350 V
• Diode max DC current: 10 mA
• Grid-anode capacitance: <0.005 pF
• Envelope material: Glass
• Filament type: Indirectly heated
• Construction: Miniature
• Cathode type: Oxide coated

Why choose it

This tube is designed for IF amplifier, detector, and AGC circuits in vintage equipment. Its variable-mu pentode allows for automatic gain control, while the diode section handles detection. The Noval base ensures compatibility with standard sockets.

Ideal use cases

• Replacement for original EBF89 or 6DC8 tubes in vintage radios
• Restoration projects for tube-based audio equipment
• DIY tube amplifier builds requiring a duodiode-pentode

Good to know

The EBF89 is a miniature glass tube with an oxide-coated cathode and indirect heating. It is equivalent to the 6DC8 and features a 9-pin Noval base.