Integrated Amplifiers

Unlike Marantz's Model 30 [HFN Jan '21], which employs the same Ncore NC500 Class D power amp module we saw in the PM-KI Ruby [HFN Jan '19] and PM-12SE [HFN Nov '20], the Model 40n sees its Class A/B output stage derived from that used in the PM8006 [HFN Sep '18]. The '40n is a considerably more evolved design, however, for while the PM8006 and '40n are both rated at 70W/8ohm and deliver a very similar 2x95W/8ohm and 2x155W/4ohm, the newcomer – with its paralleled output devices and beefier PSU – steps up with 383W/2ohm and 337W/1ohm under dynamic conditions [Graph 1]. The PM8006 was capped at just 260W/2ohm and 78W/1ohm. Overall gain, too, is similar at +42dB but the '40n enjoys a significantly wider 93.4dB A-wtd S/N ratio (re. 0dBW, vs. 85.6dB for the PM8006) just as distortion is uniformly lower at 0.0004-0.003% (20Hz-20kHz, 10W). The Model 40n's output impedance is fractionally higher at 0.05-0.06ohm (20Hz-20kHz) but its response is just that bit more extended, out to –0.1dB/20kHz and –0.9dB/100kHz.

The performance of the '40n's digital stage is determined, in part, by the choice of ESS's tried-and-tested ES9016K2M DAC implemented here with Marantz's own HDAM op-amps – jitter is fabulously low at <5psec ('Wide' or 'Narrow' lock mode), the A-wtd S/N is an impressive 109dB (via line/record outs) and THD very low at a minimum of 0.00015-0.0004% (20Hz-20kHz) over the top 20dB of its dynamic range [Graph 2]. Two digital filters are offered, with Filter 2 the more broadly 'compatible'. This is a hybrid type with asymmetric pre/post ripples, a 46dB stopband rejection and –0.9dB/20kHz, –3.3dB/45kHz and –6.8dB/90kHz responses with 48kHz, 96kHz and 192kHz media. PM