EL12 spez Telefunken Germany tube power tubes valve amplifier ela V300 Klangfilm

both tubes with gold pins 
coated glass
big tray getter bottom 
black base 
with top cap EL12 spezial 

near NOS fully tested strong emission 34mA & 26mA(good at 19mA) with 200 volt on anode 
on Funke tube tester calibrated 
Telefunken Germany original big diamond front logo
code on base , tube 1 = 663 , tube 2 = 0998 

2 tubes = pair = two pieces = 2 valves 

VACUUM PENTODE POWER OUTPUT LAST STAGE AUDIO
EL12 spez = EL12 sp
Similar tube Other base and data slightly different:   EL12N
Multiple differences or of other kind:   EL12
First serie 1939 Tube leaflet collection E.Erb Analysis by original leaflets (T8)
Socket German Steel Y8A Top contact with a cap
Filament heater Vf 6.3 Volt / If 1.2 Ampere / Indirect / Parallel, ~ = (AC/DC)
Description Launched 1938 by Telefunken.
Predecessors / Vorgänger: AL5; Successors / Nachfolger:~EL34
18 W power output pentode with almost twice the sensitivity as the AL5, intended for applications designed for normal output pentodes as the EL11, but where twice the output power is desired.
A suffix /xxx indicates the max. voltage this tube is especially selected for, otherwise it's 250 V.
The EL12 spez. has a plate top cap. The EL6 is a parallel type with P base.

box 207