4 X ECC81 TUBE. 1960s MULLARD PRODUCTION. B9A3, B7J1, B1A4, B6A1 DATE CODES. GRAY PLATES, HALO GETTER, 1 MATCHED PAIR. TESTED IN ROEHRENTEST TUBE TESTER TESTED IN AMPLITREX AT1000 TUBE TESTER 88/82% EMISSION (EM) 80/69% TRANSCONDUCTANCE (GM) 2.2/0.8mA/V GAS.
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