THE GREAT MULLARD MAGIC BLOG — ECC81

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...

Well, we're going to talk about the ECC81 twin triode today, originally designed for TV applications, yes, that's right - TV!!!!     All the other valves we have discussed in this World Series of blog entries had been designed for use at the then used British TV frequency bands of 45 - 70 MHz.  However, other countries used carrier frequencies at a much higher range within the 100 - 300MHz region at which a low noise level high grade triode would be needed so enter stage left.... the ECC81.  The ECC81 was great because it was inherently a 'low...

The advances in television since WW2 and the extension of the British TV service and indeed those of other countries brought with it the necessity to develop a more effective series of valves for television manufacture.  In order to reduce the size, weight, customer cost - and manufacturer profit margin, British TV sets were now being built using the 'transformerless technique' pioneered first in 1948. So, in 1951, Mullard introduced their World Series of TV valves comprising of the ECC81, EF80, EB91, EQ80, PL83, PL82, ECL80, PL81, PY80, PY82, EY51.  As you may deduce from the list, all were miniatue...