Sony PS-P7X turntable Lab Report

Lab Report

While this compact Sony direct-drive lacks the stature of its bigger brothers, the PS-X9 [HFN Mar '17] and PS-X4 [HFN Sep '17], it is still both extremely capable and competitive with today's budget designs. Its 31cm diecast alloy platter is brought up to speed within two seconds by a crystal-locked brushless/slotless motor that holds to a fine absolute speed accuracy of ±0.07% . Wow and flutter is low enough with peak figures of 0.03% and 0.04%, respectively, although the low-rate ±3Hz/±6Hz/±9Hz sidebands [see Graph 1] are also visible on the rumble spectrum (not shown here). Nevertheless, the DIN-B wtd through-bearing rumble remains low at –72.1dB (re. 1kHz/5cm/sec) although the through-groove measurement of –68.5dB will be influenced by your choice of pick-up stylus and whether your phono stage has a LF filter option.


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


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

The partnering J-shaped alloy tonearm is some 8.5in in effective length and 11g in effective mass, and though the latter will be influenced by your choice of headshell it will surely be compatible with a wide range of MMs and MCs. J-shaped arm tubes do not bend or twist in quite the predictable fashion of 'straight' tubes and this is reflected in a series of resonances visible in the waterfall [see Graph 2]. In practice there is a broad bending mode around 50Hz with higher-Q, but rapidly damped modes at 100Hz, 170Hz and 440Hz, the latter pair probably harmonics and/or torsional modes. Our sample was in fair condition with the gimbal bearing exhibiting a little free play but offering a mere ~15mg of friction/stiction in both planes. The static downforce calibration was good to +5%, which is better than the arms fitted to many contemporary decks. PM

Turntable speed error at 33.33rpm: 33.31rpm (–0.07%)
Time to audible stabilisation: 2sec
Peak Wow/Flutter: 0.03% / 0.04%
Rumble (silent groove, DIN B wtd): –68.5dB
Rumble (through bearing, DIN B wtd): –72.1dB
Hum & Noise (unwtd, rel. to 5cm/sec): –56.3dB
Power Consumption: 9W
Dimensions (WHD) / Weight: 430x110x350mm / 10kg