Price is for 1 what seems to be NOS dual triode preamp tube. With O-getter with one support, ribbed folded plates. Tube is produced in the 1960's at Blackburn plant in England. Etched code is: Gf2 B5F5
Tested VERY STRONG & closely BALANCED as follow!
Ia1 = 10.1 mA | S1 = 2.0 mA/V | Ri1 = 8.0 | μ1 = 16.0
Ia2 = 10.4 mA | S2 = 2.5 mA/V | Ri2 = 7.9 | μ2 = 19.8
Tested under: Uf = 12.6V | Ua = 250V | Ug1 = -8.5V
Good starts at Ia=7.0mA and 100% is Ia=10.5mA
Shipping will be Airmail registered with tracing number. Other shipping methods available on request.