The CV882 is the UK procurement specification for the commercial DH81 double diode triode that was first seen at the 1947 National Radio Exhibition.
The design use was as detector, AGC rectifier and first audio voltage amplifier in broadcast superhet receivers and effectively was the 6Q7GT on the new B8B or Loctal base.
The Type was obsolescent by early 1951. The DL82 was similar and pin compatible but had a lower amplification factor and a vari-μ characteristic.
The Z identifies the maker as MO Valve Company, Hammersmith.
The triode between the two mica discs with the cathode extended below the lower mica. The diode anodes are mounted one above the other.
A clearer view of the diode anodes.
Here is an enlargement of the diodes.
The commercial Type DH81 is also present on the envelope but no commercial branding is present.
The wide glass tube envelope is 31 mm in diameter, and excluding the B8B base pins is 57 mm tall.
