ECC81, MULLARD, TK1 R8F JUNE 1958 MITCHAM MANUFACTURE
On offer today is a lovely Mullard ECC81 manufactured in 1958 Carrying good white print markings this is a real find, testing as good using my AVO Valve Characteristic Meter VCM163 with the following results: At Va = 250V Vg = -2.0V
V1: Section 1: Ia = 10.1 mA; gm = 5.0 mA/V
V1: Section 2: Ia = 10.1 mA; gm = 5.0 mA/V
The specification for a new/100% emission valve is:
Ia = 10 mA; gm = 5.5 mA/V
As you can see, this result show a strong, well matched triode section within the envelope.
