CV4004, MILITARY SPEC, ECC83, 641 R1I6, MULLARD, BOX ANODE, MITCHAM MANUFACTURED, SEPTEMBER 1961, M8137

CV4004, MILITARY SPEC, ECC83, 641 R1I6, MULLARD, BOX ANODE,  MITCHAM MANUFACTURED, SEPTEMBER 1961, M8137

On offer today we have a Mullard white print CV4004 made at the Mitcham plant and carrying a date code for September 1961 and on the obverse an old shield M8137 notation.

For Va = 250 V Vg = -2.0V against a nominal specification of anode current Ia = 1.2 mA and mutual conductance gm = 1.6 mA/V, the following results were obtained:-

A1 Ia = 1.2 mA gm = 1.6 mA/V

A2 Ia = 1.4 mA gm = 1.7 mA/V

As you can appreciate this represents good matching of each triode section within the envelope and a device showing superb emission.