Here's the latest of my
Wireless World Quality Amplifier builds. Again I've avoided the expense of vintage PX4 or
PX25 triodes and used tetrodes. This time however they are strapped as triodes as in the classic Williamson and
Leak TL/12. Those amplifiers used a pair of Marconi KT66 beam tetrodes as triodes. Williamson reckoned the characteristics of these valves when strapped as triodes was equivalent to the PX25. I've chosen to use the less common, but now far cheaper
KT44 - actually Mazda 11E3, but they're the same valve. The KT44 is a rather different looking valve, it looks more like
an 807 - itself a variant of the popular
American 6L6G valve, much loved by electric guitar players.
The circuit is very simple. In essence it is the output valves and drivers from the Williamson, with the phase-splitter and feedback loop removed. So at present there is no negative-feedback, as in the original 1934
Wireless World Quality Amplifier.
