12AT7 (1339) - GOLD PINS MULLARD 10M SERIES - ORIGINAL BOX & PACKING FOAM (STARTING TO DISINTEGRATE DUE TO AGE)
GM = 5.08 & 4.31 mA/V
Mu = 66.7 & 62.5
VERY HEALTHY EMISSION
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12AT7/ECC81 DATASHEET NOMINAL @ 250V/-2V IS 10mA PLATE CURRENT & ~ 5.5mA/V GM AND 60 Mu