Ah - Yes!!
An excellent overview of the many designs hatching forth in the 50s - NOSTALGIA!
The main thing not mentioned (unless I missed it) is that the writer is Mr John Linsley-Hood, himself an eminent audio designer from England, from the previous century. Pleasant and informative reading and an eye-opener regarding what could be considered the start of high-fidelity equipment. Mr Linsley-Hood also pioneered a few simple transistor designs, some of which are still in use some 60 years later (obviously now with more modern transistors).
Apart from a few errors* this article is an authoritive piece of history, setting straight many misconceptions even in its brief coverage.
Note from me: The important British article "Amplifiers and Superlatives" by Williamson and Walker; Wireless World, Sept. 1952; is worth looking up by those wishing to be set straight regarding the U.L. debate.
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* Mainly, certain erroneous connections of the screen bypass capacitor from screen to earth, not cathode, of pentode stages (e.g. the Leak TL12 circuit and others).
Secondly: The detailed description of the Sonab amplifier more follows fig.17 than fig.16, particularly regarding the input circuit (some component values in fig. 16 are wrong).
