Vintage

Aiwa’s direct-drive 4-phase/8-pole ‘linear torque’ Hall effect motor gets the 1.3kg die-cast alloy platter up to speed within 4secs and, even after 40-odd years, this sample was still running to within –0.08% of 33.33rpm without adjustment. Pitch stability is good, this deck showing little or no low-rate drift, while peak-wtd wow is an acceptable 0.04% with discrete sidebands at ±6Hz and ±9Hz [see Graph 1, below]. Rumble is complex... Tested via the spindle and motor core it amounts to a vanishingly low –74.3dB (20Hz-20kHz, DIN-B wtd, re. 1kHz/5cm/sec) but it’s the unweighted spectrum [not shown here] that reveals significant resonances between 19-32Hz (–56.8dB re. 1kHz/5cm/sec) and 45-60Hz (–68.5dB re. 1kHz/5cm/sec). These are multiple and complex modes that cannot simply be laid at the feet of motor ‘cogging noise’. The two-part platter brings an added variable and despite the ‘loading platter’ being made of a fairly dense mineral-loaded plastic, the DIN-B wtd through-groove rumble is still higher – though not especially ‘high’ – at –70.8dB.

The partnering S-shaped tonearm has an effective length of just 8.5in (215mm) and an effective mass of ~14g with the supplied detachable headshell. Anything other than a straight armtube will typically show a complex series of resonances and so it is here with a low-level primary bending mode around 130Hz and other twisting or harmonic modes seen on the CSD waterfall at 185Hz, 220Hz and 270Hz [Graph 2, below]. However, these resonances are closely coupled and the higher modes at 440Hz, 510Hz, 560Hz and 590Hz are very swiftly quelled. Finally, there is some play in the automated arm bearing assembly while the counterweight calibration over-reads very slightly (so a 2g setting yields a 1.9g downforce). PM