"Goofball_star_dot_etal" wrote in message
...
On Sat, 03 Jan 2004 18:13:50 GMT, "cwvalle"
wrote:

You can't tell rotational accuracy if the test record has more w/f than
the
table under test.

True. However the measurements I just mentioned show a peak to peak
speed variation of 1.2 Hz in 303.8 =0.004 This mainly at the
rotational frequency and could be accouted for by the LP off-centre 2
thou/ inch of radius say 10 thou at radius of 5 inches. The rest of
the w/f above the second harmonic of this are down in the region of
1/10th to 1/100th of this, say +/- 0.0002. This test record is not
that bad. . .


I think that this may well be the case, we are talking about very small
values here. The strobe may also not be accurate enough.
The only way to do this would be to set up some kind detector on the
platter
itself and this could measure the accuracy of rotation.

There is more than one way to skin a cat.

The effects of the
tone arm, and cartridge however cannot be determined this way.

In the example I showed (300_1-fmfft.jpg) there is very little FM to
be seen at the tone arm resonant frequency of around 10 Hz

The crux of the problem is that turntable performance can only be
measured
in a partial way. Even if the exact same test record were used to compare
tables, the combination of effects could mask defects, or exaggerate
them.
The net result however is as you say, a lot better than a kick anywhere


I would be delighted to process your test tone with my polar plotted
FM detector(tm). I expect to see a flower shape with petals
corresponding to the number of poles but we may never know. You might
not like what you would see but at least it would test your and
other's beliefs mentioned in Message-ID:

If I were you I would chicken out. . . On the other hand the width of
the plot published in Stereophile might just be due to a hole in a
record being off-centre.


I do not have the WAV file that I sent to JA and he used to produce that
graph.
I can make another one if you want.

I have several test records

Command Stereo Check Out - CSC 100
Telarc Digital Omnidisc - DG-10073, '74

The Telarc is the one I use as a standard, and is the one i used to make the
WAV file I sent to JA

I have a CBS STR 100, 102 but I dont know where it is right now

There is no way I chicken out. Not now not ever
Specify your email and you will get a tone

my email is