Luxman PD-191A Turntable Lab Report

Lab Report

There are close parallels between this new PD-191A, its predecessor PD-171, and the earlier PD-151 [HFN Oct '19] which was one of the first Luxman decks to employ a new 'high torque' brushless DC motor. The motor is retained here and mounted directly onto a heavy, rubber-damped bottom plate, bringing the 5.2kg platter up to speed within 5 seconds via a substantial EPDM rubber belt. It's not uncommon to see a sub-1Hz drift with decks that employ a DC motor solution, but Luxman's PWM/PID speed controller clearly provides 'direct-drive standard' low-rate speed stability, seen in the sharpness of the main W&F peak [see Graph 1, below]. However, this same plot also reveals a ±8-9Hz high-rate wow amounting to a peak-wtd 0.06% which is unfortunate but not subjectively problematic. Speed adjustment of ±6% allows precise pitch stability to be achieved.

Luxman's sealed stainless/brass bearing assembly, with PEEK thrust pad and molybdenum oil, is familiar and achieves a direct rumble figure of –68.8dB (DIN B-wtd). The heavy rubber mat provides significant damping, reducing the through-groove rumble and noise to just –72.6dB. Meanwhile the partnering 'not quite S-shaped' LTA-710 tonearm offers an effective 256mm (10in) length, a 15g effective mass and exhibits a clearly defined main tube mode at 140Hz with harmonic/secondary resonances at 290Hz and 375Hz [see CSD waterfall, Graph 2]. Friction from the vertical knife-edge bearing is <15mg while the 'dial up' counterweight is precisely calibrated, under-reading by just 4% at 1g (1.04g) and 1% at 2g (2.02g). Just make sure you take time to dynamically balance and settle the arm before gently turning the circular indicator to read '0' at the 12 o'clock position. PM

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Wow and flutter re. 3150Hz tone at 5cm/sec (plotted ±150Hz, 5Hz per minor division)

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Cumulative tonearm resonant decay spectrum, illustrating various bearing, pillar and 'tube' vibration modes spanning 100Hz-10kHz over 40msec

Turntable speed error at 33.33rpm 33.34rpm (+0.03%)
Time to audible stabilisation 5 seconds
Peak Wow/Flutter 0.06% / 0.02%
Rumble (silent groove, DIN B wtd) –72.6dB
Rumble (through bearing, DIN B wtd) –68.8dB
Hum & Noise (unwtd, rel. to 5cm/sec) –62.6dB
Power Consumption 4W (4W idle)
Dimensions (WHD, inc. lid) / Weight 491x186x393mm / 26.4kg
Price £11,000 (+£1500 with LMC-5 cartridge)

COMPANY INFO
Luxman Corp.
Japan
Supplied by: IAG (International Audio Group), UK
01480 447700
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