Re: No, No NO!
"They tests their MkII valve ampr (1% distortion) , their 33/303 transistor amps (0.1% distortion) against the 404/44 (0.01%)setup.Not one of the golden ears could accurately tell the difference in double blind testing."
It would be interesting to know what music they were listening to. There was a test of this conducted in the USA back in the early 1970s with a doctored Phase Linear amp (IIRC). The listening panel was presented with various music recordings — flute, piano, violin, voice etc — at different levels of harmonic distortion (THD). THD had to be quite high ~10% to be audible on some content, but was clearly audible at 1% on different content.
It's worth noting that THD varies with the output power of the amplifier. Traditionally it was measured at the amplifier's maximum rated output. Class B amplifiers generate high distortion at quite low levels. Most of the time amplifiers are idling along at a fraction of their rated output.
Two other distortions had already become apparent back then. Crossover distortion in the common Class B amps of the day, and transient intermodulation distortion. The first was overcome by Class A designs though these were only half as efficient as Class B and the second by making amplifiers capable of handling frequencies well in excess of the standard 20 kHz which being beyond the limit of human hearing was considered to be more than adequate.