"Mike Coatham" wrote

During a tidy up I found a 6 page article on "Square Wave Testing of Audio
Amplifiers" in the NZ publication - Radio & Electrical Review - of August
1955. In it, it goes on to describe the testing of amplifiers using square
waves as a relatively new process.


In an advertising pamphlet from Haynes Radio that I have; undated but
probably from the late 1940s, there is the following sentence at the end of
the description of their "Quality Amplifier":-

quote
Amplifier designs are developed with the aid of a square wave-form
generator, which experience has shown will reveal defects unobserved by
tests with oscillator and distortion factor meter, and upon which quite
misleading test data might be based.
unquote

Incidentally this Amplifier (£18.10s plus £6.15s for the PSU) uses 4
triodes, including a pair of PX4s in the output stage.

David.