AD1M Datasheet

The AD1M  is a beautifully constructed tube, and it is a Mesh Version of the AD1.  This tube is fully compatible to the original Telefunken AD1, using original NOS sockets. 

This  tube uses AVVT's unique Open Filament structure, resulting in high linearity, even at the maximum  output signal  (Note1


  • Original double V-shaped filament. 
  • Two large getters
  • White Mesh Wire Plates
  • ST Glass shape like historical tubes. 
  • Anti-microphonic Suspension in Tube Top
  • Hard-metal filaments, which can never break. ( Note2)

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Night view

AD1M    Filament Ratings 
Filament Voltage 
4 Volt
Filament Current 
AD1M     Maximum Conditions  See  Note 3
Plate Voltage 
Plate Current 
Anode Dissipation 
Power Output in Class A
AD1M    Typical Data
Plate Voltage 
Plate Dissipation 
12,5 Watt 
Plate Current 
Grid Voltage 
Plate Impedance 
800 Ohm 
Amplification Factor 
5 mA/V 
Load Impedance
2400...5500 Ohms
Grid Resistor
100k Ohm
Operating Lifetime 
40.000 hours 
AD1M    Mechanical Data 
Tube Size including Socket: 158 x 60mm 
Tube Weight 
135 Grams
AD1M Socket Dimensions

Telefunken P5 Socket
enlarge 5x 

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Note 1) Open Filaments means, the filaments and the grid are longer than the Anode, 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 anode, and land on the glass. At maximum Power this may cause fluorescent, blue glow on the tube glass inside.  Mesh tubes may develop a fluorcescent blue glow om the Plate.   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

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