6DJ8 ECC88 (1666) - ULTRON (IN WEST GERMANY PRINTED BOX)
GM = 15.99 & 13.15 mA/V (12.5mA/V SPEC)
Mu = 32.7 & 32.7 (33 SPEC)
VERY STRONG EMISSION
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6DJ8/ECC80 DATASHEET NOMINAL @ 90V/-1.3V IS 15mA PLATE CURRENT & ~ 12.5mA/V GM AND 33 Mu