AV 300B / 300M Datasheet


Direct Replacement:

AVVT 300B replace by EML 300B

AVVT 300M replace by EML 300B-Mesh


We have two versions: The standard tube, called 300B,  and a special version with mesh plates, called 300M. 

The AV 300B is a direct replacement for the WE300B.    The AV300M can also replace the WE300B, but only in amplifiers that work with a  lower dissipation.  There are two versions of the 300M.   The first type 300M can work up to a plate dissipation of 17Watt. The second generation AV300M can work up to 27Watt. 


  • 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 
  • Unbreakable Hard-Glass / Globe Glass /  C37 Glass 
  • Anti-microphonic Suspension in Tube Top (not with Globe tubes) 
  • Unbreakable hard-metal filaments. (Note2
  • Ceramic UX4 Socket with Gold Plated pins 

17Watt or 27Watt  Mesh Version 
Detail1 - Detail2 - Large

Attention: NEVER  put this is a standard 300B amplifier without first checking the plate dissipation!
GL Glass
globe bulb
for pure vintage sound 
C37 Glass. Designed by 
Dieter Ennemoser, for natural sound. 

There is a noticable sound difference between C37 glass and Globe glass, because of the different way the tube system is contacted to the glass.   The GL Globe Glass is a  retro design, back to the origin of the great triodes, still valued 65 years later.  It has almost no interaction between the glass and the tube, and you can hear the triode sound in it's purest way.  The C37  design has larger mechanical damping of the inner tube system, and produces a very natural sound.   This design is made by Dieter Ennemoser, who is a  violin builder, who has done works for well known brands, including Sony.  We build the C37 glass shape in licence.   The difference in sound is small, but can be very clearly heard when comparing both tubes.

AV 300B / 300M Filament Ratings
Filament Voltage 
5 Volt (AC or DC) 
Filament Current 
1.3 Ampere 

AV 300B / 300M Maximum Conditions
(See also Note 3)
Plate Voltage 
Plate Current 
Plate Dissipation 
Power Output in Class A 

AV 300B / 300M Typical Data 
Plate Voltage 
Plate Dissipation 
18 Watt 
Plate Current 
Grid Voltage 
Plate Impedance 
640 Ohm 
Amplification Factor 
6.1 mA/V 
Load Impedance 
1500 - 3500 Ohm 
Operating Lifetime 
40.000 hours 
Grid resistor
100k Ohm

AV 300B / 300M  Mechanical Data
170 x 65mm (Includes Socket) 
Weight Standard Version 
142 Grams 
Weight C37 Version 
135 Grams 

For further information about our products, please visit

Note 1)  Super Linear Plates 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 plate, 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

Tube pictures with courtesy of VT-Components

JAC-MUSIC  ©2001. All Rights Reserved.