Technics SL-10 turntable Lab Report

Lab Report

Because the SL-10's four-pivot, gimbal-suspended linear-tracking arm is servo-driven in response to the lateral force exerted upon it by the cartridge, the scope of each incremental adjustment is very largely influenced by the eccentricity of the LP in play. Spectrum analysis reveals the so-called 'bump/thump' as a momentary increase in the noise floor from ~20-80Hz although its subjective impact is arguably less obvious than the mid/high frequency clicks, scratches and pops from a less-than-silent LP surface. Residual hum and noise is determined by both the integral preamp and susceptibility of the pick-up (an A-T AT85EP in this instance), and amounts to –85dBV, or –60dB relative to 1kHz/5cm/sec [black spectrum, Graph 2 below]. The through-groove rumble of –70dB (DIN-B wtd) is a very fine result and up with the very best decks of today.


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


Unweighted rumble and hum over 0-500Hz range (black, arm lifted; blue, arm in silent groove)

It is impossible to provide our traditional through-spindle/motor rumble measurement because of the deck's 'closed format' and integral clamp. However, the unweighted through-groove rumble [blue trace, Graph 2] is dominated by a low frequency mode at 13-15Hz (–57dB re. 1kHz/5cm/sec) and this same resonance can be seen as complex ±14Hz sidebands on the wow and flutter spectrum [Graph 1, above]. This contributes to an aggregated, peak-wtd flutter of just 0.04%.

Technics' quartz-locked brushless DC motor brings the alloy platter up to 33.3rpm within 1.5secs and holds it to an absolute speed accuracy of –0.09%. Peak wow is very low at 0.02% [main signal, Graph 1] and while there's some slight broadening of the 3150Hz signal it's gratifying to see none of the sub-1Hz drift that still afflicts so many belt-driven decks utilising DC motor solutions to this day [HFN Feb '19]. PM

Turntable speed error at 33.33rpm 33.30rpm (–0.095%)
Time to audible stabilisation 1.5sec
Peak Wow/Flutter 0.02% / 0.04%
Rumble (silent groove, DIN B wtd) –69.7dB
Rumble (silent groove, unwtd) –57.0dB
Hum & Noise (unwtd, rel. to 5cm/sec) –59.7dB
Power Consumption 10W
Dimensions (WHD) / Weight 315x88x315mm / 6.5kg