Siemens EF 800 = EF 860 Electron Tube, Noval Base, Pentode, 6.3 V Filament, 1 pc

The Siemens EF 800 = EF 860 is a high-frequency pentode electron tube with a transconductance of 6.5 mA/V and an equivalent noise resistance of 2.5 kΩ, making it suitable for low-noise audio and RF applications. It features a Noval (B9A) 9-pin base and operates with a 6.3 V filament at 0.2 A.

Overview

This glass-envelope pentode is designed for high-frequency and low-noise audio circuits. It offers a maximum anode voltage of 300 V, a maximum screen grid voltage of 200 V, and typical operating points of 8 mA anode current and 1.5 mA screen grid current at 250 V anode and 170 V screen grid with -2 V grid bias. The tube is equivalent to types EF800, 6BR8, and 6F22.

What stands out

• High transconductance of 6.5 mA/V for excellent gain.
• Low equivalent noise resistance of 2.5 kΩ for clean signal amplification.
• Noval 9-pin base for easy integration into existing circuits.
• Equivalent to EF800, 6BR8, and 6F22 for flexible substitution.

Technical details

• Tube type: Electron tube (pentode)
• Function: High-frequency / low-noise audio pentode
• Base type: Noval (B9A), 9 pins
• Filament voltage: 6.3 V
• Filament current: 0.2 A
• Max anode voltage: 300 V
• Max screen grid voltage: 200 V
• Typical anode current: 8 mA (at Va=250 V, Vg2=170 V, Vg1=-2 V)
• Typical screen grid current: 1.5 mA (at Va=250 V, Vg2=170 V, Vg1=-2 V)
• Transconductance: 6.5 mA/V (at Va=250 V, Vg2=170 V, Vg1=-2 V)
• Internal resistance: 0.5 MΩ (approx.)
• Equivalent noise resistance: 2.5 kΩ
• Equivalent tube types: EF800, 6BR8, 6F22
• Envelope material: Glass

Our verdict

A reliable pentode for demanding low-noise and high-frequency applications, with documented specs and common equivalents.