Sensibly equivalent¶ to:
55B/400A 5894/C178A 5894A 5894 CV2797 TT25
The QQV06-40A is a 1950s European pattern double beam tetrode VHF transmitting valve. The European pattern had internal neutralising unlike the American pattern valves such as the 829B that required external neutralising capacitors to prevent oscillations.
This is an excellent example of good design. The two beam tetrodes with a maximum anode dissipation of 40 W have been built round a central flat cathode. A split control grid (one half per valve) followed by a common screen grid and beam plates completes the central assembly. The anodes are single plates held in place by the top pins. In all a symmetrical valve ideally placed for push-pull VHF operation.
The heater is centre tapped to allow for 12.6 or 6.3 volt operation, and this made the design particularly good for mobile transmitters.
In use the designer would take care to keep the grid circuitry below the chassis with the anodes being connected to circuits remote from the input. This way undesirable feedback could be avoided.
The internal capacitors for neutralisation can be seen at the top of the valve as short pieces of wire attached to the grid supports.
The wide glass tube envelope is 44 mm in diameter and, excluding the B7A base pins, is 72 mm tall.
References: Datasheet & 1040.
Absolute Maximum Operating Conditions¶
Updated December11, 2015.