Part Number : EL34
Function : OUTPUT PENTODE PEDTHODE DE SOTRIE ENDPENTODE
Manufactures : Philips Semiconductors
The EL34 was introduced in 1953 by Mullard and its parent company Philips and, although no longer made by them, is manufactured by JJ Electronic, Shuguang, Svetlana and Reflector (Sovtek, Electro-Harmonix, Tung-Sol and some brands), amongst others. Some firms make a related tube called an E34L which is rated to require a higher grid bias voltage, but which may be interchangeable in some equipment.
EL34 is a glass envelope power pentode having a plate dissipation rating of 25 Watts with convection cooling. It is intended for audio frequency power amplification service in either pentode, ultralinear or triode connection and single or push-pull/parallel applications. The Vacuum Tube has an indirectly-heated oxide cathode, which may be DC operated for the absolute best hum/noise performance.
Reference site : https://en.wikipedia.org/wiki/EL34