The EAT ECC88 is a special quality double triode. The tube satisfies the specifications in accordance with MIL-E-1/1J168 (NAVY) from 18.6.1958.
Tight tolerances: In these tubes the tolerance of electrical ratings are reduced in comparison with standard tubes.
Vibration and shock proof: The tube withstands accelerations of 2,5 g at 50Hz for lengthy periods and momentary shocks of 500g for short periods.
Cathode free from Interface: The cathode establishes no interface even in case where the heated tube is operated without plate current over lengthy periods.
Heather voltage: The average heather voltage should be 6,3 V.
Variations of the heather voltage exceeding the range of 6,0 V to 6,6 V will shorten the tube life. The tolerance of heather current (column II) should be taken into account.
Substitutes: E88CC, 6DJ8, 6922