The CV2666 is the 829B American pattern VHF double tetrode. The American approach to twin VHF transmitting beam tetrodes was to put two separate valves within the single envelope. This design requires external neutralisation capacitances to prevent parasitic oscillations.
The European design double tetrode VHF transmitting valves used a common cathode with independent g1's, a common g2 and single sheet anodes (seeQQV03-20 and QQV06-40A) had internal neutralisation and made the 829B and 832 obsolete.
The envelope has a bulge of 54 mm diameter that was used for retaining rings.
Currently, designs exist to use all of the VHF double tetrodes as audio amplifiers, these are physically beautiful devices and deserve to be seen.
One of the box anodes. Note the use of ceramic insulators as anode voltages can be high.
The anodes looking along the grid axis.
The wide glass tube envelope is 51 mm in diameter and, excluding the B7A base pins, is 95 mm tall.
