Type CV1958 is designed to operate in push-pull Class B2 with zero grid bias. The anode to anode load is given as 8,000 Ohm. It is specifically an audio power valve capable of 10W per pair. Provided plenty of HT voltage is available it can also be used, with both halves connected in parallel, Class A1, as a power driver for another CV1958.
The CV1958 specification is identical to the commercial 6N7GT and both Type designations are present on this exhibit.
Type 6A6 is electrically the same valve but on a UX7 base.
One anode with side flange for greater radiating area. Note the cooling fin on the top of the copper grid support.
The two triodes side by side.
The wide glass tube envelope is 28 mm in diameter, and excluding the IO base pins, is 64 mm tall.
References: Datasheet, 1040 & 1043. Type CV1958 was first introduced in 1936.