This part is a kind of semiconductor called EL34.
Function of this product has A.F. Output Pentode.
Manufacturers : Ei-RC
Image and pinout :

Some of the text within the PDF file :
"Ei-RC" - Electronic tubes factory EL34 EL34 is A.F. Output Pentode suitable for use in power amplification Data Sheet Page 1 of 9 Quick reference data • Anode current Ia=100mA • Transcoductance S=12,5mA/V • Amplification µg2g1=11 • Output power, Class B WO=100W Heating Heating is indirect by AC or DC, with parallel supply. Heater voltage Heater current Vf 6,3 If 1,5 (V) (A) Telephone: FAX: Postal address: Electronic mail: Web site: +381 18 550 741 +381 18 550 806 Bul. Sv. Cara Konstantina 80-86, 18000 Nis, Yugoslavia eirc@eierc.com http://www.eierc.com/rc "Ei-RC" - Electronic tubes factory EL34 Dimensions and connections Base: Octal Data Sheet Page 2 of 9 Telephone: FAX: Postal address: Electronic mail: Web site: +381 18 550 741 +381 18 550 806 Bul. Sv. Cara Konstanti [ ... ]
EL34 PDF Datasheet Download
