Musical Fidelity M6 Vinyl Phono Stage Reviewed

My recent system overhaul required me to look for a replacement phono stage. I wanted a flexible preamplifier with both MM and MC compatibility, accurate RIAA correction and adjustable loading with a low moving magnet capacitance setting of 100PF or less. Multiple inputs would be nice too as would balanced operation. I decided to take the Musical Fidelity M6 Vinyl for a spin as it seemed to meet my needs perfectly, measures very well and is an aesthetic and theoretically ideal technical match to my M8sPRE preamplifier and M6sPRX power amplifier.

M6vinyl Front Black

It’s an impressive beast on paper, with MF claiming it to have no practical limits in its input stage or output driving capacity. It adheres closely to the RIAA or the later RIAA/IEC specification (selectable), within 0.2dB on both MM and MC with an additional post RIAA filter in place to retain accuracy to beyond 80kHz. The equipment I have on hand to measure is only accurate up to about 40kHz, at which the M6 Vinyl easily met its specification. Levels of noise and distortion are exceptionally low at -96dB (MM) and -86dB (MC) reference to a 2V RMS output, and just 0.008% THD across the audio band.

It can output 10V RMS (single-ended) and 20V RMS (balanced) with an overload margin of 31dB. This is all powered by a sizeable toroidal power transformer with seven separate PSUs across each channel. Each stage within the M6 Vinyl remains fully balanced with perfect star grounding.

Input loading (MC) is selectable between values of 10Ω, 25Ω, 50Ω, 100Ω, 400Ω, 800Ω and 1k2Ω. MM loading is fixed at 47KΩ. Input capacitance (MM) is selectable between 50PF, 100PF, 150PF, 200PF, 250PF, 300PF, 350PF and 400PF. MC capacitance is fixed at 470PF. An additional +6dB of gain is selectable, as are both RIAA and RIAA / IEC filters.

The M6 Vinyl will store the configuration for each input. All settings are relay switched and accessed via a row of neat controls on the front fascia, with LEDs indicating the value of each setting. A muting function prevents unwanted pops and thumps in the speakers, allowing the circuitry a few seconds to settle on power-up and after each setting or input change.

Also on the front are controls for power and input selection, with Musical Fidelity’s distinctive bevelled design and machined name badge.

M6 Vinyl Rear Black

Around back are chunky input and output terminals, the latter balanced but the inputs single-ended only. This seems an odd omission given the balanced typology, but with most tonearms being wired for unbalanced operation as standard isn’t a major drawback. The terminals are of the type usually found in pro audio gear and are a great deal better than you’d normally find on a consumer hi-fi component, especially at this price. Power is via a standard IEC jack, and there’s a single ground terminal to be shared between the three inputs.

The casework is well put together with a smart aesthetic in black or silver. It comes double-boxed with generous foam supports, wrapped in a cotton cloth drawstring bag with a spiral-bound instruction manual and cotton gloves for handling. It’s a nice unboxing experience and a pleasing first impression.

I’ve used the phono stage with a range of cartridges. These include the entirety of Audio-Technica’s VM95, VM500 and VM700 moving magnet lines, along with the classic AT95 (moving magnet) both with its original stylus and an upgrade aftermarket Shibata. I’ve also used my own AT33PTG / II (moving coil). A Sumiko Moonstone (moving magnet) stopped here on review briefly and was also used, as was an Ortofon 2M Black (moving magnet) and Rega’s Apheta2 and Aphelion (both moving coil). Most cartridges were installed on my Technics SL-1200G, though a couple found their way onto my Thorens TD-150, now fitted with static isolation rubber mounts as opposed to the suspension springs.

At the heart of a phono stage is amplification. That is to take the tiny input signal from a phono cartridge and bring it up to line-level. Average output from a moving magnet cartridge is 5 millivolts or so, where a line level input typically has a minimum sensitivity of at least 150 – 200 millivolts. Moving coil cartridges require considerably more gain as their output is measured in microvolts. Such a level of Tain brings with it the risk of excessive noise obtruding into the signal from the amplifiers and also the cables which can act as antennas and pick up unwanted airborne interference.

The phono stage must also apply equalisation to the signal following the RIAA standard, reversing the equalisation applied during the cutting process without which a stylus would be unable to track a record properly if at all. This equalisation and any other filtering (subsonic filtering for example) must be carried out with considerable accuracy to avoid colouring the output from the cartridge. And of course, a phono stage must be capable of matching well to the cartridge, providing optimal load characteristics as improperly loading can further colour the cartridge’s output.

So while a phono stage may appear a simple device, executing a design that can perform all of the above to a high standard is not a trivial task. It’s fortunate then that Musical Fidelity’s engineering team know a thing or two about amplification, and applied all of this knowledge to the design of the M6 Vinyl. The result is a neutral phono preamplifier with impeccable performance, a neutral character and vanishingly low levels of noise.

With such extensive headroom, the M6 Vinyl remains free of distortion or overload when fed a cartridge with a healthy output, yet is quiet enough that it performs equally well when the cartridges output level is significantly below average, such might be something like a high output moving coil fed into a moving magnet gain stage. It just sounds ‘right’, in the way that the partnering M6sDAC does for digital audio. Nothing is added, nothing is taken away, the character of each cartridge allowed to flourish with a background blacker than black, a tremendous sound stage and endless dynamics.

Thanks to the adjustable loading, the M6 Vinyl proved more than a match for every cartridge I had to hand. Audio-Technica’s moving magnet cartridges are especially sensitive to a high capacitance, becoming brutal at the top end if you go much about 250PF or so, and becoming harsh and rather unpleasant when you go above 300PF or so. Dropping the M6 Vinyl to the 50PF setting, in conjunction with a total cable capacitance also of around 50PF brought the best out of these carts

M6 Vinyl Front Silver

The M6 Vinyl is a terrific phono stage. With the convenience of switchable inputs, plenty of adjustment, accurate RIAA equalisation and a neutral sound, it’s an ideal phono preamplifier. Highly recommended.

By Ashley

I founded Audio Appraisal a few years ago and continue to regularly update it with fresh content. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. A musician, occasional producer and sound engineer, other hobbies include software programming, web development, long walks and occasional DIY. Follow @ashleycox2

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