2x TESLA ECC802S / 12AU7WA. of original TESLA ECC802S tubes. These are industrial-grade tubes made for army or aerospace use, and other demanding applications. Datecodes: FW = 4/1974. Tube 2: Ia1=3.10mA / Ia2 =3.40mA, S/gm1= 1.10 mA/V / S/gm2= 1.20 mA/V.
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