THE MULLARD WORLD SERIES OF TELEVISION VALVES

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 B9A valves except for the EB91 double diode and the EY51 EHT boost diode.