"Ei-RC" - Electronic tubes factory Data Sheet Page 1 of 4 ECC81/12AT7 www.datasheet4u.com ECC81 is R.F. Double Triode Quick reference data Anode current Ia=10mA Transcoductance S=5,5mA/V Amplification ยต=60 Heating Heating is indirect by AC od DC, with serial or parallel supply. Please note that, in case of serial supply, a current limiting device must be inserted in the heater circuit for limiting the current when switching on. Heater voltage Heater current p.