In Reply to: The dialogue started privately with JA.... posted by Charlie8521 on February 14, 2018 at 08:59:00:
>The Stereophile review of the Z-Man ASE where JA changed a well established
>and documented Bench Test load...
I assume you are referring to the fact that I tested the ASE into 1k ohms
as well as into 100k ohms and 10k ohms. From the August 1997 review:
"Fig.7 shows the spectrum of the ASE's output reproducing 50Hz at 1V into
10k ohms, this a typical level and the load lowish but not untypical of
some of the preamps or power amps out in the real world....Though it is
high compared with the levels plotted in fig.6, at -60dB or 0.1% it should
have no audible consequences. But when the load was dropped to a punishing
1k ohms (fig.8), the second harmonic rose to an audible -32dB (around 3%),
and was joined by third, fourth, and fifth harmonics. This intolerance for
low impedances can be seen in fig.9, which plots the THD+N percentage
against output voltage for three loadings: 100k, 10k, and 1k ohms..."
Note that in Stereophile's reviews, I routinely test preamps, disc players,
and digital processors into loads as low as 600 ohms, to reveal the devices'
worst-case behavior. You are incorrect to say that the ASE was an
exception to my established test procedure by being tested into 1k ohms.
See for example, fig.4 at the review linked below.
And as this was 21 years ago, I fail to comprehend why you are publicly
raising this issue now.
John Atkinson
Technical Editor, Stereophile
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Follow Ups
- RE: The dialogue started privately with JA.... - John Atkinson 11:00:49 02/14/18 (0)