"Jem Raid" wrote in message

"Arny Krueger" wrote in message
...
"Jem Raid" wrote in message


I remember that John Linsley-Hood did something similar in 1969
comparing valve and transistor amps, he reported that there was very
little difference.

I wonder what he thought "was very little difference"?

Here is the 1969 article from Wireless World,
http://www.tcaas.btinternet.co.uk/jlh1969.pdf

Outstandingly clean text scan! Thanks, this is a classic.

"Unfortunately, it is not possible to simulate under laboratory conditions
the complex loads or intricate waveform structures presented to the
amplifier when a loudspeaker system is employed toreproduce the everyday
sounds of speech and music"

This problem has been addressed he

http://www.pcabx.com/product/amplifiers/index.htm

"The possession of a good standard of reference is a great help in
comparative trials of this nature, and
the author has been fortunate in the possession, for many years, of a
carefully and expensively built
"Williamson" amplifier, the performance of which has proved, in listening
trials, to equal or exceed, by
greater or lesser margins, that of any other audio amplifier with which the
author has been able to make
comparisons."

www.pcabx.com reintroduces an old absolute standard - effectively a straight
wire. Practically speaking the standard is actually a straight wire
stretched between two audio interfaces, but the sonic properties of those
audio interfaces are up for public inspection at:
http://www.pcabx.com/product/cardd_deluxe/index.htm

The 'Williamson' referred to is a valve amplifier in case that isn't
too clear.

Good point, because I believe there was also a SS Williamson that was heavly
promoted in the US by a magazine then called Audio Amateur.

"However, in the past, when these tests were made for personal curiosity,
and some few minutes could
elapse in the transfer of input and output leads from one amplifier to the
other, the comparative
performance of some designs has been so close that the conclusion drawn was
that there was really
very little to choose between them.:

This can now be easily reduced to an arbitrarily short period of time.

I think that our current standards for "sounds the same" are far more
sensitive.