Vacuum Tube Data Sheets


   The 12AX7 / ECC831 is a miniature, high-mu twin triode, each section of which has an individual cathode connection.  The construction of the 12AX7 / ECC83 is such that noise and microphony are reduced to a minimum.  Hum is reduced by the use of a coiled tungsten heater.  A center-tapped heater permits operation of the tube from either a 6.3 volt or a 12.6 volt heater supply.

   The 12AX7 / ECC83 is particularly suited for use in resistance - coupled voltage amplifiers such as those used in the preamplifier and input stages of Hi-Fi amplifiers, phase inverters, multivibrators and numerous industrial control circuits where high voltage gain is desired.


Cathode Coated, unipotential
Series Paralleled
Heater Voltage, AC or DC 12.6 6.3 volts
Heater Current2 0.15 0.3 amps
Direct Interelectrode Capacitance's With Shield3 Without Shield
Grid to Plate (each section) 1.7 1.7 uuf
Input (each section) 1.8 1.6 uuf
Output (section 1) 1.9 0.46 uuf
Output (section 2) 1.9 0.34 uuf
Maximum Overall Dimensions
   Length 2 3/16 inches
   Seated Height 1 15/16 inches
   Diameter 7/8 inches
Mounting Position any
Base Small button, 9 pin

   1 The 12AX7 / ECC83 is a direct, high-quality replacement for other brands of the 12AX7.

   2 When used in equipment which employs series - connected heaters, a current-limiting device must be inserted to limit the current when switching on.

  3 With external shield (RETMA #315) connected to cathode of section under test.

Vacuum Tube Data Sheets

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