Australian Hi-Fi 27
Mag-Lev Audio ML1 Turntable
20 Hz 50 100 200 500 1K 2K 5K 10K 20KdBm-40-35-30-25-20-15-10-505Graph 1. Ortofon^10 NewportTestLabs
OM10 Frequency
Response and Channel
Separation as installed
in the Mag-Lev Audio
ML1 turntable.Newport Test Labs first measured the fre-
quency response, channel separation and
output voltage of the Ortofon OM10 phono
cartridge in order to see whether the powerful
magnetic fields affected these aspects of
its performance by changing the flux lines
of the magnets inside or saturating the
coils. The frequency response and channel
separation are shown in Graph 1. You can
see that the frequency response of the OM10
(black trace) is very flat between 30Hz and
20kHz, varying no more than ±1dB across
this frequency range. This is an excellent
result. Below 30Hz, the response rolls off to
be 8dB down at 20Hz. Channel separation,
as measured by Newport Test Labs, is shown
as the red track on Graph 1, and you can see
that at 1kHz, it was 17dB. This is 5dB less
than Ortofon’s specification of 22dB. It may
be that this particular (well-used) sample was
out of specification, but may also be that the
channel separation was adversely affected by
the strong magnetic field... or not.
Newport Test Labs found the speed accuracy
of the Mag-Lev Audio ML1 was exact at both
33.33rpm and 45rpm, with the turntable
replaying a 3kHz sine wave recording at
exactly 3kHz at 33.33rpm, and a 3.15kHz
sine wave at exactly 3.15kHz at 45rpm. The
lab found that measuring the wow and flutter
of the Mag-Lev Audio ML1 was complicated
by the fact that any air movement in the
laboratory would cause the platter to ‘wobble’
slightly, which always increased the levels
Laboratory
test
report
of wow and flutter that were measured. At
33.33rpm, Newport Test Labs measured wow
and flutter at 0.13% unweighted RMS, and at
45rpm, it measured 0.12% unweighted RMS.
Although these results are higher than those
returned by most high-quality turntables
(for which the lab usually measures figures
of between 0.04 and 0.09%) they’re still low
enough to ensure wow and flutter would not
be audible. The lab noted that the platter was
moving very slowly up and down at the time
the measurement was obtained so you can
achieve low levels of wow and flutter even if
the platter is wobbling slightly.
Newport Test Labs also experienced techni-
cal difficulties measuring the rumble (aka sig-
nal-to-noise ratio) of the Mag-Lev Audio ML1,
because the lab’s standard test technique
involves using a mechanical device made in
Germany known as a ‘Rumpel-Messkoppler.’
In this case, because the Rumpel-messkop-
pler was too heavy for the platter and also
made of ferrous metal, plus using it requires
making an alignment that can only be done
whilst a platter is revolving, it could not be
used at all. The lab instead resorted to usinga far older measurement technique that
required acquiring an acetate master specially
cut with a ‘no signal’ groove. Using this test
technique, Newport Test Labs measured the
signal-to-noise ratio of the Mag-Lev Audio
ML1 as being 75dB unweighted below refer-
ence level, that level being a 1kHz signal cut
at a recorded velocity of 3.54cm/sec. This is
the best result the lab has ever measured for
any turntable and 2dB better than claimed by
Mag-Lev Audio.
Putting the matter of the reduced channel
separation of the OM10 cartridge aside as an
issue requiring further investigation, there’s
no doubt that—under ideal conditions—the
levels of wow and flutter contributed by the
Mag-Lev Audio ML1 are imperceptibly low,
its speed accuracy is perfect, and the level of
rumble is not only also imperceptibly low
but also the lowest that Newport Test Labs has
ever measured. That’s impressive... very, very
impressive.
Overall, given the design principle, I can
only say that the overall performance of the
Mag-Lev Audio ML1 is amonumentaltech-
nological achievement. Steve Holding