AV 320B SL Datasheet

This tube is a version of the  AV32B,  designed for the VAIC amplifiers.  The  main difference  with the AV32B is the more rugged construction.  It has larger cooling  plates, and a larger bulb size. 


  • This tube uses AVVT's unique Super-Linear Patent (Note1) 
  • AVVT's patented ribbon filaments with 16 flat Surfaces, for more linearity 
  • Two extra large getters 
  • Internal cooling plates and metal encapsulated tube base for  minimized grid current
  • Unbreakable Hard-Glass. Bulb is larger sized than normal 32B. 
  • Anti-microphonic Suspension in Tube Top 
  • Uses unbreakable hard-metal filaments. (Note2
  • Ceramic UX4 Socket with Gold Plated pins

AV 320B SL
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AVVT 320B Curves

AV 320B SL Filament Ratings
Filament Voltage 
5 Volt (AC or DC) 
Filament Current 
2.4 Ampere 
AV 320B SL Maximum Conditions     (See also Note 3)
Plate Voltage 
Plate Current 
Plate Dissipation 
Power Output in Class A 
AV 320B SL Typical Data     (See also Note 4)
Plate Voltage 
Plate Dissipation 
60 Watt 
Plate Current 
Grid Voltage 
Plate Impedance 
525 Ohm 
Amplification Factor 
6.5 mA/V 
Load Impedance 
1500 - 3500Ohm 
Grid resistor
50k Ohm
Operating Lifetime 
40.000 hours 
AV 320B SL Mechanical Data
180 x 65mm (Includes Socket) 
Weight Standard Version
220 Grams 

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Note 1)  Super Linear Anodes are based on an exclusive AVVT patent.  The cold ends of the filaments do not have a very good function, and cause distortion.  This tube has  four cavities inside the anode, that cover the cold ends of the filaments. These cavities are covered by four nickel plates, that you can see from the outside.  Within these cavities, anode current will not be able to flow,  and this disables the emission of the cold end of the filaments.
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 has  is numbered, inside the bulb  with a metal Tag
Note 4 Typical Data  When operated at lower power level, refer to typical data of the 300B for mu, transconductance, and Plate Resistance.  You can test this tube with normal  300B settings, given that the tube tester can do 2.4Amps filament current. 

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