The CV788 (commercially the 832A) is a dual transmitting beam tetrode. The design is of the American type with two separate valves sealed into the single element.
The oval oval anodes enclose the beam plates, grids and heater cathode assembly. This type of construction usually required external capacitors to neutralise parasitic oscillations. These normally being vertical wires alongside the envelope.
This type of dual valve was obsolete by the start of the 1960s replaced by the QQV03-20 or QQV06-40A varieties for VHF transmitters. It is typical of these RF power tetrodes that the base connections all match one another.
With the revival of valve audio in the 21st century the dual valve approach gives a clearer audio response probably as the design was based on the 6V6 originally. The European pattern QQV03-20A et al were designed from the start for Class C RF use or Class B modulators - not for music reproduction.
The KB/Q identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the Q identifies the maker as English Electric Valve Co., Chelmsford.
The bright beam plate within the oval anode. Note the ceramic insulators as voltages of 600 V DC could be used and under modulation the peak would be much higher.
The twin sections.
The top caps are pins like the base and need special connectors.
The B7A base with central evacuation pip.
The wide glass tube envelope is 51 mm in diameter and, excluding the B7A base pins, is 71 mm tall.
