Vintage

Technics’ ‘New Class A’ refers to a sliding/dynamic bias regime that aims to keep the complementary output stage free of crossover distortion without the wasteful constant current dissipation of a traditional Class A circuit. We would expect to see distortion reduced at very low signal levels but, in practice, while this seems to be the case under dynamic conditions [black trace, Graph 1], it’s less obvious with steady-state signals. Here distortion is already a very low 0.001-0.005% at 1W but falls still further to 0.0008-0.003% at 10W [all re. 20Hz-20kHz into 8ohm; see Graph 2]. These figures are all lower than Technics’ specification at the time, just as its 65W/1kHz/8ohm power rating was demolished at 2x90W (and 1x105W) on test in 2026.

Into 4ohm, the SU-V5 produced 2x130W (1x160W) and enjoyed sufficient headroom to accommodate 130W, 215W, 320W and 361W into 8, 4, 2 and 1ohm loads, respectively, under dynamic conditions [Graph 1]. So the SU-V5 was a very capable integrated indeed, even though the power meters – on this sample at least – were only accurate to 1W/8ohm, drifting thereafter so that a 10W/8ohm output appears as 3W on the scale and 20W as 5W...

The response shows a gentle HF roll-off, amounting to –0.23dB/20kHz and –3.3dB/100kHz, but is actually ‘flatter’ with the DC servo omitted in ‘tone mode’, reaching –0.0dB/20kHz and falling more steeply beyond 85kHz (–1dB) to –2dB/100kHz. As expected, with DC coupling fully engaged, the ‘bass’ extends down to +0.45dB/1Hz. Otherwise, the A-wtd S/N is not out of the ordinary at 83.5dB (re. 0dBW), bearing in mind that the overall amplifier gain is high at +43.8dB, requiring just ~150mV to reach the rated 65W output. PM