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Audio Technica AT-OC9 MLIII
Measured Performance
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Frequency response of the popular AT OC9 MLII peaked above 8kHz, giving bright treble. Audio Technica have cured this in the MLIII, it now measures almost ruler flat. It still isn’t quite as flat as rivals but it gets close enough, having a frequency response that stays unerringly close to the 0dB datum right up to 20kHz. Inner groove tracing loss introduced a small amount of treble fall above 10kHz.
   At a tracking force of 1.7gms tracking was excellent, even torture tracks were cleared at 300Hz and 1kHz. The new MLIII is a great tracker if used close to its upper VTF limit. 
   Output was fair, measuring  0.57mV at 5cms/sec rms and this will suit most moving coil phono stages.
Vertical tracking angle was almost correct, measuring 24 degrees. As a result distortion was very low at 1.5% on vertical modulation. Lateral distortion was also very low, measuring just 0.5%.
    The updated AT OC9 in MLIII guise measures very well all round and is a highly developed design. NK


Tracking force    1.25-1.75gms
Weight    8gms
Vertical tracking angle    24degrees
Frequency response    20Hz - 20kHz
Channel separation    26dB
Tracking ability (300Hz)
lateral    90µm
vertical    45µm
lateral (1kHz)    25cms/sec.
Distortion (45µm)
lateral    0.5%
vertical    1.5%
Output (5cms/sec rms)    0.57mV




Red - inner grooves



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