The new M6si integrated amplifier improves on the outgoing M6i model with more inputs and completely new internals to give greatly improved technical and sonic performance. The M6si has real high-end sound quality. Because of its power it is effortless and unstressed. Its stability margins are huge so it will drive any loudspeaker easily. These are only the bedrock for what the M6si really does: sounding fantastically musical. Because of its pre amp/power amp configuration it produces wide stable images with an effortless, clear, ungrainy sound quality. Bottom end is delivered with a vast punch and speed of attack. All in all the M6si offers true high-end sound quality, an extensive range of useful inputs, a compact package, reliability and a fair price.
M6si – Design and Build
We felt that the original M6i’s package size, power and price were spot on. What was needed was the addition of extra input facilities and, if possible, an all round improvement of technical performance. By the way, despite endless component price rises during the M6i’s life, we didn’t alter its selling price. This made our final requirement even harder; the M6si should not be significantly more expensive than the outgoing model.
First we determined to use Musical Fidelity’s exclusive SMD layout techniques. This reduced the size of the circuit’s footprint and gave us greatly increased flexibility with internal layout. Consequently the new M6si is configured as a pre amp with two completely separate and independent monobloc power amps. The M6si is a proper pre amp with its own separate regulated power supply and discrete monobloc power amps, sharing same casework. This is a big change from the outgoing M6i. The M6si’s technical performance is a significant advance on the old model.
The M6si performs immaculately. Because of its pre amp with two monobloc power amp configuration both channels perform virtually identically, just what you would expect from a pre amp with separate power amps and not what you would expect from a normal integrated amplifier. The M6si is a cut above everything else. Distortion is very low at less than 0.005%. More tellingly, HF distortion is incredibly low. At 10 kHz about 0.006% and at 20 kHz an astonishing 0.007%.
The vast majority of amplifiers suffer huge increases in distortion as you go up in frequency. The M6si’s meticulous PCB and circuit design means that HF performance is virtually identical to the LF performance. This is significant for sound quality. Channel separation is remarkable, and remarkably consistent. Most amplifiers (integrated or pre/power) have dramatically worsening cross talk with increasing frequency. The M6si cross talk is outstanding and even at 20 kHz it is better than 82dB. The phono stage is also special. It has very accurate RIAA, within ± 0.5dB from 20 Hz to 20 kHz. Also it maintains its accuracy right out to 50 kHz. The MM noise ratio is an outstanding 93dB down whilst the MC stage is, perhaps even more amazingly, about 87dB down. The phono stage distortion is a very low 0.01%. All in all the M6si’s phono stage is exceptional.
The 24 bit 96 kHz asynchronous USB input uses exactly the same circuitry and technology as our highly regarded V-Links and other top quality computer interfaces. Jitter is virtually eliminated. Noise is incredibly low and distortion virtually non-existent. The M6si’s USB input is capable of dredging the finest details from the computer source.