Pre/Power Amplifiers

The beefier of Micromega's two M-One amplifiers is reinforced by a PFC (Power Factor Correction) version of its RPS power supply. Rated at 150W/8ohm, the M-150 delivers 2x167W/8ohm and 2x315W/4ohm with 175W, 335W, 565W and 690W available under dynamic conditions into 8, 4, 2 and 1ohm loads [see Graph 1]. These are impressive, load-tolerant figures for such a slimline amplifier with a Class A/B, rather than Class D, output stage. Distortion is very well controlled too, holding true to a mere 0.0009-0.0014% across its rated 150W power bandwidth from 20Hz-1kHz. Distortion increases at HF, but not excessively – reaching 0.01%/10kHz, 0.017%/20kHz and 0.035%/40kHz. The response of the amplifier is limited by internal sample rate conversion to –0.55dB/20kHz, –2.0dB/40kHz (–35dB/48kHz) via the analogue inputs and –0.4dB/20kHz to –2.6dB/45kHz via its digital inputs but the output impedance is low and 'flat' at 0.04-0.05ohm from 20Hz-10kHz so there's little variation in response between 8, 4 and 2ohm loads. The A-wtd S/N ratio is 'average' at 83dB (re. 0dBW).

The digital board, based on AKM's AK4490 'Velvet Sound' DAC, is configured with its linear phase/steep roll-off filter and offers 94dB of stopband rejection, delivers a resolution good to ±0.3dB over a full 110dB dynamic range and offers a 107dB A-wtd S/N ratio (balanced line output). Distortion is 0.0002-0.002% (20Hz-20kHz, 0dBFs) and falls to a minimum of 0.0001-0.0005% between –10dBFs and –30dBFs over the same frequency range [see Graph 2]. Jitter is impressively low at <40psec for all sample rates, though any files at 176.4kHz and higher are downsampled to 96kHz/32-bit. PM

Continuous power (<1% THD, 8/4ohm): 167W / 315W
Dynamic power (<1% THD, 8/4/2/1ohm): 175W / 335W / 565W / 690W
Output impedance (20Hz–20kHz): 0.043–0.095ohm (315ohm, pre)
Freq. resp. (20Hz–20kHz/40kHz): +0.0 to –0.55dB/–2.0dB (Analogue)
Distortion (20Hz-20kHz, 0dBFs/0dBW): 0.0002–0.002%/0.0006–0.017%
A-wtd S/N ratio (re. 0dBFs/0dBW): 107.1dB (Dig) / 83.1dB (Analogue)
Digital Jitter (48kHz/96kHz): 40psec / 25psec
Power consumption (idle/rated o/p): 40W / 480W (3W, standby)
Dimensions (WHD / Weight): 430x56x350mm / 9.3kg
Price: £5390-£6190