ECC40

Small Signal Triode — Rimlock

Philips

Known Equivalents & Substitutes

CV3884AA61

Similar Tubes (Not Drop-In Compatible)

6SN7GT

Medium-mu dual triode (mu=20) on Octal base; listed as predecessor by Philips, similar application as LF amplifier/phase inverter

Medium-mu dual triode (mu=17) on Noval base; Philips successor to ECC40, lower mu but similar circuit roles

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Max Anode Voltage300V

Anode Dissipation (max)Max Anode Dissipation1.5W

Cathode Current (max)Max Cathode Current10mA

Heater-to-Cathode Voltage (max)Max Heater-Cathode Voltage175V

Max Grid ResistorMax Grid Resistor1MΩ

Typical Operating

Anode Voltage (typical)Anode Voltage250V

Grid 1 Bias VoltageGrid Voltage-5.6V

Anode CurrentAnode Current6mA

Anode ResistanceInternal Resistance11,000Ω

TransconductanceMutual Conductance

Capacitances

Grid-to-Plate CapacitanceGrid-Anode Capacitance2.7pF

Input CapacitanceInput Capacitance2.8pF

Output CapacitanceOutput Capacitance1.1pF

Heater

Heater VoltageHeater Voltage6.3V

Heater CurrentHeater Current0.6A

Notes

Philips Rimlock-era design introduced in 1948, superseded by ECC82 on Noval base from 1951.
Two identical triode sections with completely separate cathodes; heaters connected in parallel internally.
Maximum heater-cathode voltage is 175V (heater negative) or 100V (heater positive), notably higher than typical E-series valves.
Can be used without special microphony precautions when input voltage is at least 5 mV for output of 50 mW.
Each section heater draws 0.3A; total heater current is 0.6A at 6.3V.

Pin Layout — Rimlock

1Anode 1 (Triode section 1)

2Anode 2 (Triode section 2)

3Control Grid 1 (Triode section 1)

References