Similar ratings but B8A side-contact base vs Octal — not pin-compatible
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)600V
Screen Voltage (max)Screen Voltage (max)425V
Anode Dissipation (max)Anode Dissipation (max)18W
Typical Operating
Anode Voltage (typical)Anode Voltage400V
Notes
Anode is connected via top cap — not available on the octal base pins.
Pin 3 is unused (no connection). Suppressor grid (g3) is on pin 6, which differs from the EL38 where g3 is on pin 1.
4654K is the octal-based variant and is pin-compatible with the EL39.
EL50 and 4654 (P8A base) are sometimes listed as equivalents but have different ratings — they are not direct substitutes.
For push-pull stages, it is inadvisable to employ high anode voltages unless the grid bias is fixed.
The 4654 datasheet specifies a maximum anode voltage of 600V; the EL50 datasheet shows operation at 800V. Use 600V as the safe maximum unless the specific tube variant is confirmed as EL50-rated.
Pin Layout — Octal
1No Connection
2Heater
3No Connection
4
Socket-Compatible Tubes ⚠ Not electrically compatible