12AX7 is a tiny dual triode vacuum tube with a high gain in voltage. It was developed by RCA engineers in 1946 and was released for sale to the public in 1947. It has nine socket connections and has a maximum voltage of 300 V. It is made of two triodes and a double diode triode.

Originally, it was intended to be a replacement for the 6SL7 family which is made of dual-triode amplifier tubes for audio applications. It is popularly used in guitar tube amplifiers and its use in such equipment makes it few of the small signal vacuum tubes that are being produced continually.

12AX7 ECC83 Datasheet

According to its datasheet, some of the main specs of the tube are:

  • Amplification of 100
  • Has separate cathodes
  • Has maximum overall length of 56mm
  • Has a maximum diameter of 22.2mm
  • It has a total of 9 plates which are terminal connections 

The following are the key application areas for the tube:

  • Low level audio voltage amplification
  • Guitar tube amplifiers 
  • Resistance-coupled voltage amplifiers
  • Phase inverters
  • Numerous industrial control circuits 
  • Various other low-level frequency terminals

12AX7 ECC83 Pinout

12AX7 has eight pins. Pin 1 is the Shell 6V6 pin and pin 2 is the heater pin. The plate pin is the third pin and the fourth pin is the screen grid. The fifth pin is the control grid and the sixth is the none pin. The seventh and eighth pins are the heater and cathode pins respectively.

12AX7 ECC83 Equivalents and Replacement Details

The equivalent of 12AX7 are 12AX7A, ECC83, ECC803S, E803CC, B759 and 12AD7. Any of these can be used interchangeably for 12AX7 but it is recommended to check the pinout and electrode information before use.

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