Musical Fidelity M6si

M6si - Overview

The new M6si integrated amplifier is much more than just an upgraded predecessor model. It has several additional inputs and a completely new inner workings, which have greatly improved both technology and sound quality. Its power makes it effortless and unaffected by low impedances, and its stability reserves are so large that it can drive virtually any speaker. All this is the basis for what the M6si is designed to do above all: deliver fantastic sounding music. Because of its elaborate preamp / power amp configuration, it produces big stable sound images with effortless, clear, very fine resolution. Its bass has tremendous punch and punch with high-speed attitude.

All in all, the M6si offers true high-end sound quality with a large selection of useful inputs - a compact package, reliable and at a fair price. Stereoplay summed it up in its 9/2014 issue: "High-quality processed, ultra-solid integrated amplifier - powerful and very connection-friendly with phono section and USB input. Colourful, powerful bass, stringent, yet lively sound - also via phono and USB."

M6si - Technical background

We felt that the original M6i package size, performance and price were right on the money. What was needed, however, was expansion with additional input options and - if at all possible - an all-round improvement in technical performance. A small side note: Despite endless price increases for the individual components of the M6i, we never changed its retail price. This made meeting our latest demands even harder; the M6si should not be significantly more expensive than the outgoing model. First, we decided to use our exclusive surface mount technology here as well. This reduced the size of the PCB footprint and significantly increased our flexibility in terms of schematics. Subsequently, we designed the new M6si as a preamplifier with two completely separate and independent monoblock power amplifiers. So we are dealing with a real preamplifier with separately regulated power supply plus discrete monoblock power amplifiers that only share one cabinet. This drastic change is the reason for the significant improvement over the outgoing M6i. The technical performance of the M6si is also significantly better than that of the old model.

Power

Because of its configuration of preamplifier with two monoblock power amplifiers, both channels work almost completely independent of each other - what you would actually expect from a preamplifier with separate power amplifiers, but not from a normal integrated amplifier. The M6si is simply far above average in everything. Distortion is very low at less than 0.005%. More tellingly, HF distortion is incredibly low, around 0.006% at 10 kHz and an astonishing 0.007% at 20 kHz. As soon as the frequency goes up, the vast majority of amplifiers suffer from a huge increase in distortion. It is our opinion that the HF power must be practically identical to the LF power. This is of great importance for the sound quality. The channel separation of the M6si is remarkable and particularly consistent. With most amplifiers (integrated or preamp + power amp), crosstalk deteriorates dramatically with increasing frequency. The M6si's crosstalk, on the other hand, is excellent and still better than 82dB even at 20 kHz.

The phono stage is also outstanding. It has a very precise RIAA setting that deviates just ± 0.5 dB from 20 Hz to 20 kHz. It retains its precision up to 50 kHz. The MM signal-to-noise ratio is an excellent 93 dB, with the MC stage perhaps even more amazing at over 87 dB. The distortion of the phono stages is a very low 0.01%. As I said: absolutely exceptional.

USB input

The 24-bit 96 kHz asynchronous USB input uses the same technology as other top computer interfaces - not least our highly regarded V-Links. Jitter is virtually eliminated here. Noise is incredibly low and distortion is virtually non-existent. The M6si's USB input is capable of extracting the finest details from the computer source.

M6si - Technical data

• Output power: 220 watts per channel into 8 ohms
• Distortion values: <0.007 % 20Hz - 20 kHz
• Signal-to-noise ratio: >107dB 'A'-rated
• Frequency response: +0, -0.1dB, 10Hz to 20 kHz

Inputs

• 4x high level RCA
• 1x high level XLR (balanced)
• USB input type B up to 24 bit 96kHz USB audio stream

Phono input

• Sensitivity: 3mV nominal (MM), 0.4mV nominal (MC)
• Signal to noise ratio: >84dB 'A'-weighted
• Input impedance: 47 k Ohm (MM and MC)
• Frequency response: RIAA/IEC ±0.5dB 20Hz-20kHz

General

• Dimensions - W x H x D (mm): 440 x 125 x 400
• Weight (unpacked / packed): 16.6 kg / 21.3 kg