In late 1952, a new range of Mullard B9A Noval based valves having 6.3V heaters were introduced aimed at use in audio amplifiers.
PRE-AMPLIFIER - type EF86 now replaced the EF37A or EF40 having similar charcteristics to the EF40 with a gain of up to 140 being achievable. The heater of the EF86 is rated at 6.3V @ 200mA.
DOUBLE-TRIODES - three new devices were made available - the ECC81 being a medium impedance valve, the ECC82 a low impedance and the ECC83 a high impedance. All designs have independant cathodes for each section, centre tapped and capable of operation at 12.6V @ 150mA or 6.3V @ 300mA.
OUTPUT PENTODE - the EL84 meets the demand for an output valve with 30% more output than the EL41. A single EL84 was designed to give an output of 5.4W with 10% THD. A pair of EL84 in Class AB1 push-pull could deliver 16W. The heater of the EL84 is rated at 6.3V @ 800mA.
FULL-WAVE RECTIFIER - the EZ80 has identical characteristics to the EZ40 and is capable of a rectified output of 90mA at a maximal voltage of 2x 350V RMS. The heater of the EZ80 is rated at 6.3V @ 600mA.