12AX7/ECC83 Mullard Vacuum Tube: Pinout, Specifications, And Diagrams.pdf

## 12AX7/ECC83 Mullard Vacuum Tube - Electrode-to-Lead Connection & Specifications Summary

This summary outlines the key aspects of a 12AX7/ECC83 Mullard vacuum tube, focusing on its electrode connections and technical specifications.

Pin Arrangement:

The tube features the following pinout:

1-9: Anode (positive) pins numbered sequentially from top to bottom.

Lead Designation:

First Triode:
Anode (A1) - Pin 1
Grid (G1) - Pin 3
Cathode (C1) - Pin 5
Second Triode:
Anode (A2) - Pin 6
Grid (G2) - Pin 8
Cathode (C2) - Pin 9
Heater:
Heater - Pin 2 & 4 (parallel connection)

Electrode Name:

As per standard convention, the electrodes are named based on their function:

First Triode:
Plate, Grid, Cathode
Second Triode:
Plate, Grid, Cathode
Heater: Heater

Technical Specifications (Key Points):

Dimensions: 56.5mm max length, Ø22.5mm maximum diameter.
Amplification Factor: 175 - 390 (depending on operating conditions).
Heater Current: 350 mA at 6.3V filament voltage (varies with grid voltage).
Plate Current: Up to 288 mA for both triodes combined (differences between triodes within ±20%).
Operating Voltage:
Plate: 250 V (fixed bias)
Filament: 6.3V or 12.6V (series connection for higher voltage)
Grid: Variable depending on desired current and voltage (see data table).
Power Dissipation: 1.0 - 1.2 W per triode.
Insulation Resistance:
Cathode-Heater: ±200 MΩ
* Grid Circuit: 1.0 MΩ per triode.

Limiting Values (Eg):

The breakdown voltage between the plate and cathode (Eg) can be as low as -3V, indicating the maximum allowable reverse voltage across each triode.

Note: The provided data table offers detailed information on current and voltage characteristics at various operating points.