AV8B  Datasheet


No Replacement



These tubes are designed for driving Power Tubes that need a high input voltage on the grid, such as the 300B,  AD100,  and simular tubes. Other applications are:  Interstage Transformer driver, Phase Splitter driver.   Also it can be used a an Output Tube, producing maximum 5Watt Single Ended. 

It uses AVVTs unique Open Filament structure, resulting in extreme linearity, also at high output voltage. (Note1


  • AVVT's parallel ribbon filaments with 16 flat Surfaces, for more linearity
  • Two large getters
  • White  nickel plates
  • C37 Shaped Glass
  • Anti-microphonic Suspension in Tube Top
  • Hard-metal filaments, which can never break. ( Note2)
  • Ceramic UX4 Socket with Gold Plated pins

AV 8B SL, white nickel plates
Clicke here for Plate Curves

Mother of all AVVT white plate tubes

 Filament Ratings 
Filament Voltage
5 Volt  (AC or DC)
AC only as loudspeaker End-Stage
Filament Current 
1.3 Ampere 
Maximum Conditions     See  Note 3
Plate Voltage 
Plate Current 
Plate Dissipation 
Power Output in Class A
Typical Data
Plate Voltage 
Plate Dissipation 
11 Watt 
Plate Current 
Grid Voltage 
Plate Impedance 
1500 Ohm 
Amplification Factor 
5,5 mA/V 
Load Impedance
4000 - 8000 Ohms
Grid Resistor
100k Ohm
Operating Lifetime 
40.000 hours 
Mechanical Data 
170 x 60mm (Incl.Socket) 
130 Gram 

For further information  please visit:

Note 1) Open Filaments means, the filaments and the grid are longer than the Plate, and stick out on both ends for about 5...8mm. The not fully warm ends of the filaments do not have a very good function, and cause distortion. This tube doesn't use this part of the filaments. Emitted electrons from the cold ends, will bypass the Plate, and land on the glass. At maximum Power this may cause fluorescent, blue glow on the tube glass inside. See also our Tech Brief on Blue Glow in Tubes. 
Note 2) Hard-metal filaments are operated at much higher temperature than normal tubes. This tube will glow bright orange, instead of the dark orange color of nickel filament tubes. 
Note 3) Individual Test data, such as: Matching Data, Grid Current, Vacuum, Filament Current, etc, are on the Certificate that comes with each individual Tube. Each tube  is numbered, inside the glass with a metal Tag

Tube pictures with courtesy of VT-Components

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