Vintage

Built in 1979, well before the advent of rare-earth magnets and other technologies, Hitachi’s ‘brushless, slotless and coreless’ DC servo motor drives the HT-660’s die-cast platter with a stability that still eludes all but a very few of today’s belt-driven turntables. The requested speed is achieved in under two seconds and absolute speed was just –0.06% slow in our sample. Peak wow is a very low 0.015%, illustrated by the sharp 3150Hz tone [see Graph 1, below], while peak flutter is an equally innocuous 0.035%. Neither was Hitachi’s ‘Unitorque’ motor inclined to suffer ‘cogging’ noise, as evidenced by the low –68.5dB DIN-B wtd through-bearing rumble. The brand’s choice of thick rubber mat attenuates this still further, so the all-important through-groove rumble is a fabulously low –73.5dB (all 20Hz-20kHz re. 1kHz/5cm/sec). An FFT of the motor/bearing [not shown here] reveals a noise component at ~21Hz that’s also visible as sidebands at the base of Graph 1. Hum and noise is otherwise low at –62.0dB (again, re. 1kHz/5cm/sec).

The partnering 220mm effective length tonearm has a moderate 16g effective mass – the detachable headshell is of deliberately lightweight but still fairly rigid alloy construction – making it suitable for use with medium-compliance MMs of yesteryear and today. Otherwise, the chromed alloy arm tube has a moderate main bending mode at 110Hz [see CSD waterfall, Graph 2] alongside bolder harmonic, twisting and other modes at 185Hz, 260Hz and 333Hz. The latter, and short-lived resonances beyond, are likely associated with the headshell. The bearings, meanwhile, offer a low <20mg stiction/friction but show some slight signs of play, while the rear counterweight is accurately calibrated (1g = 1.04g; 2g = 2.07g). PM