6P6

The 6P6 in the Amalgamated Wireless Valve document is an RF power pentode with its suppressor grid on a separate contact. The sheet specifies suitability for suppressor-grid modulators and gives an example as a frequency doubler. Its function differs from an ordinary audio output valve: the doubler's useful output is at the drive signal's second harmonic. These details concern the documented AWV version, not every valve whose name starts with 6P6.

The source refers to RMA release no. 65 dated 25 March 1936, sponsored by Amalgamated Wireless Valve Co., Ltd., and calls the data tentative. That dates registration documentation, not by itself certain market introduction. The cathode is indirectly heated and unipotential. The heater requires 6.3 V AC or DC at 0.7 A. Bulb code is ST-14, with anode connection through a small metal top cap.

The pentode frequency-doubler example uses DC anode voltage 450 V, screen voltage 200 V and control-grid bias about −120 V. Listed DC currents are anode 40 mA, screen 16 mA and control grid about 2 mA. These are application operating conditions, not absolute maximum ratings. Grid current is significant: this is a driven regime unlike small-signal operation with an always-negative grid and negligible grid current. No operating frequency absent from the sheet has been added.

Listed interelectrode capacitances are grid to anode 0.7 pF, input 8 pF and output 12 pF. The sheet uses historical µµF notation, equivalent to picofarads. For an RF valve these accompany its construction and connections, but do not alone define usable bandwidth or a maximum frequency. The scan does not allow a sufficiently certain reading of the second-harmonic output-power figure, so it is not transcribed as a verified value.

The base is described as medium six-pin, with a bottom-view drawing: 1 heater, 2 suppressor, 3 screen, 4 control grid, 5 cathode, 6 heater; the top cap is the anode. The suppressor is thus accessible at pin 2 rather than an inaccessible internal connection. Handwritten annotations on the available material have not replaced the printed wiring. ST-14 is not a millimetre dimension, and the sheet has no dimensioned mechanical drawing for recording diameter and height.

Documentation consulted: Amalgamated Wireless Valve Co., Ltd., 6P6, tentative RF power-pentode data associated with RMA release no. 65 dated 25 March 1936, containing heater data, capacitances, a frequency-doubler example, and base and anode-cap connections.