Vintage

Judging by the results of my lab tests, the convenience achieved by Sony's small form-factor 78mm 'platter' and offset, semi-auto arm mechanism comes at a cost. Rumble, for example, is high at –63dB (DIN-B wtd, re 1kHz/5cm/sec) directly from the servo-controlled 'linear torque' BSL motor/bearing and is higher still at –62dB (DIN-B wtd, silent groove) via an unsupported, spinning LP disc. Absolute speed was some –0.4% slow in our 30-year-old sample but it's the levels of wow and flutter that would be more debilitating, subjectively [see Graph 1, below]. The combined, peak-wtd figure of 0.45% is about 10x higher than anticipated from an 'audiophile' deck of today.

The fitted tonearm is more complex than it looks as the pivot point is offset by an L-shaped linkage to the main, square-section alloy tube. The resonant behaviour of this structure is necessarily complex with a main mode at 110Hz followed by twisting and possible harmonics at 170Hz and 270Hz [see Graph 2, below]. The sequence of higher frequency modes will be related to the cartridge mounting, arm 'bearing' and auto-lift/lower mechanism, but despite their number these are relatively low in amplitude. Also, while the tube is a mere 150mm in length, the effective length is closer to 165mm and the effective mass very low at ~6g. As described by Tim the downforce is preset at 2g although, with Sony erring on the side of caution, in practice this was about 10% higher at 2.17g. This, the high MM compliance and 0.6mm spherical stylus profile combine to yield an adequate tracking limit of ~70µm via the left/right channels and just letting go at the penultimate +15dB groove modulation (re. 315Hz/5cm/sec) at ~1% THD. PM