2 Volt Variable-mu Pentode type VP2
Since the last edition of the Mullard Valve Catalogue, very considerable developments have taken place in the design of battery valves, with the result that to-day the performance of a modern battery-operated receiver closely approaches that of its all-mains counterpart.
The extent to which Mullard has contributed to this revolution in design and construction may be gauged from the range of valves described in the following pages.
The most important of the 1934-35 innovations are the new Mullard battery HF Pentodes, types VP2 and SP2. Following upon the success of the Mullard mains HF Pentodes, these additional types need little introduction. It can be said, however, that by reason of their high amplification factor and low internal capacity, they permit every advantage to be taken of the efficiency of modern coils, thus very greatly increasing the sensitivity of the 1935 battery receiver.
The introduction of a 2-volt Double Diode Triode type TDD2A facilitates the application of AVC to battery receivers.
Neither has the output side of the battery receiver been neglected, for the introduction of additional Mullard types provides interesting alternatives in high-efficiency audio power amplification. Thus the PM22C pentode is designed to give a large AC output with low mean anode current consumption when used in conjunction with a suitable HT economiser circuit; and the continued popularity of Class B output is catered for by the addition of the Mullard back-biassed valve type PM2BA as an alternative to PM2B.
The following links lead to a PDF of pages from the original catalogue.VP2 Variable-mu HF Pentode, SP2 HF Pentode, PM12M Variable-mu HF Screened Grid, PM12A Screened Grid, TDD2A Double Diode Triode, PM1HL Detector and general Purpose Valve, PM2DX Detector and general Purpose Valve, PM2A Power Output, PM202 Super Power Output, PM22A Output Pentode, PM22C Output Pentode, PM2B Class B Output and PM2BA Class B Output.