MUSICAL FIDELITY M6x 250.7 Review: Muscular Fidelity

Mark Craven wrestles this beefy multichannel amplifier into place, and then gets drunk on power. Read our MUSICAL FIDELITY M6x 250.7 Review.

Here’s something I wasn’t expecting. Musical Fidelity, the audio brand known for its high-end hi-fi products, and association with turntable maker Pro-Ject, which acquired the company in 2018, has launched a seven-channel power amplifier. And it’s a big old beast of an amp too.


1. Front-panel LEDs for each channel denote power status

Available now via UK distributor Henley Audio, the M6x 250.7 is the first of three multichannel amplifiers incoming from Musical Fidelity – apparently there are five-channel and 11-channel models, based around the same technology, due to launch. This begs the question of whether the manufacturer will also unleash a multichannel processor, but there’s no word on such a thing yet. Still, as I wrote in my recent review of the seven-channel Emotiva BasX A5 (HCC #335), multichannel power amps aren’t exactly common, so even if Musical Fidelity doesn’t add a partnering processor, I’m not going to grumble.

Backside story

If any processor does arrive, it will no doubt offer a balanced output to match the M6x 250.7’s seven balanced inputs, on XLR connections, found on the rear panel. There’s also the option of an unbalanced connection via RCA. Musical Fidelity doesn’t, however, provide the usual switch to select between the two. Don’t connect both types at once, then…

Other back panel features include something else a little unusual – seven further RCA output terminals. These enable the input signal to be fed to the adjacent amplifier output, for bi-amping. There are also in/out triggers for system integration (with on/off switch), IEC socket and power button, and a bank of well-spaced gold-plated multi-way speaker terminals.

The front panel is, as expected, uncluttered. Musical Fidelity says it ‘gives you a clear understanding of what is going on with the amplifier,’ which basically means there are small LED status lights for each channel, and a standby button.

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Those who believe the principle espoused in Jurassic Park of ‘if it’s heavy, it’s expensive’ might imagine the M6x 250.7 sells for more than £, because it tips the scales at an impressive 32.5kg. Consideration should be given to this when deciding where to place it, as should its dimensions – this amplifier is slightly wider than standard at 45cm, as well as 43cm deep and nearly 20cm high. It sits on four chunky chrome-finish feet.

Because of its size, its presence will be felt unless you rack it away out of sight, but the all-metal chassis (available in either black or silver), with bevelled milled aluminium fascia, does at least look quite smart.

Quiet please!

The amp’s weight is explained by Musical Fidelity’s use of Class A/B amplifier technology, and the presence of not one but two toroidal transformers. These are in-house ‘audiophile-grade’ Super Silent designs, also seen in the company’s stereo hardware including its M6x DAC (HCC #334), and, says Musical Fidelity, are a key part of the amp’s ‘high dynamic range and detailed soundstage’.

Beneath the pressed steel lid, the M6x 250.7 features a neat modular construction, with the seven individual power modules lurking behind the twin transformers. The audio circuit design follows the ‘same principles’ as other models in the brand’s upper-tier M6 series.


PRODUCT:Seven-channel Class A/B power amplifier with balanced input
POSITION:First of three new multichannel amps from Musical Fidelity
PEERS:NAD Masters M28; Emotiva XPA-DR3; Primare A35.8

Each amp module gets it own side-mounted heat-sink, allowing Musical Fidelity to eschew any internal cooling fans that might whirr into action and spoil your enjoyment of a movie.

The two proprietary toroidal transformers are split between the amps, so one feeds four channels and the other feeds three. I suppose this means that the M6x 250.7 could have easily been an eight-channel design if the manufacturer desired – but, of course, seven channels makes perfect sense in an AV environment, and adding another Class A/B module would have made the amp even wider…

The quoted output is 250W per channel (with a 400W ‘peak’) although this is into a 4ohm load – Musical Fidelity doesn’t give an 8ohm figure, but you could expect it to be around half of the 4ohm rating. And, yes, this amp promises the same power whether you are using the ‘AMP1’ or ‘AMP7’ speaker terminals, meaning your surround channels will benefit from just as much grunt as your LCR stage.

Juice me up

Big amp, big sound. That would be my ‘in a nutshell’ verdict of the M6x 250.7. There’s a scale and weight to its delivery of multichannel mixes that mirrors its physical presence. It sounds deliriously powerful, and able to give any likely partnering loudspeaker the juice it requires to perform at its best. If you need more grunt than what’s on offer here, it’s probably because you’re running wilfully inefficient high-end speakers in a cavernous listening room, and can therefore afford suitable monoblocks.

For everyone else, Musical Fidelity’s seven-channel machine will more than do.

The barrage of ballistic effects that accompanies the opening credits/battle sequence in Terminator Genisys (4K Blu-ray) was presented by the M6x 250.7 with serious slam, poise and low-end menace. As Skynet hardware flies overhead, and Resistance weaponry is discharged, the soundfield feels alive with energy.

Using GoldenEar’s BRX models (see p54), this amp proved a dab hand at making ‘small’ speakers sound absolutely huge. Bass details, whether in the film’s portentous musical score (especially the dramatic notes that accompany the title reveal), or the chunky metallic sounds of the future war scenes, came across with an extra layer of weight. And stepping up to a Polk Monitor XT 5.1.2 Dolby Atmos array (HCC #330), the helicopter escape sequence in the film’s final act (‘you can fly, right?’) was a showcase of brutal surround effects: machine gunfire, whirring chopper blades, the swoop of the helicopter as it ducks between buildings.


2. Two proprietary transformers feed the seven individual amp modules

‘There’s a scale and weight to the M6x 250.7’s delivery of multichannel mixes that mirrors its physical presence’

Magic act

This is a lively amp, too, despite its appearance perhaps suggesting otherwise. Yes, you might find more of a sense of sheer finger-snap attack on a rival Class D design, but the M6x 250.7 is no slouch. Far from it: the action of Terminator Genisys comes across with speed and dynamics. Meanwhile, having matched amps for all channels gives the soundfield a massive feeling of uniform scale, even though it’s the LCR stage that most showcases the power on tap.

Musical Fidelity rates its new amp’s total harmonic distortion at an ultra-low 0.003% (at 100W). In use, its output sounds impressively pure and clean. Details and nuances across the audio band aren’t air-brushed. Switch to film material where the mix is more subtle, such as Harry Potter and the Prisoner of Azkaban (4K BD), and the M6x 250.7’s focus becomes less about brute force and more about picking out the ambience of the varied locations. The gentle early morning suburban sounds as the young wizard flees 4, Privet Drive are presented with a deft touch, as are the outside-the-carriage rattling sounds of the Hogwarts Express. Then when the Dementor boards the train, the amp nails the variety of details in the layered soundmix, presenting the freezing water on the window pane with a spine-tingling clarity, before unleashing a dynamic thump as the carriage rocks and rumbles.

There’s also a musical side to the M6x 250.7 that brand loyalists will be expecting. Fed stereo tracks, the soundstage it creates is miles wide, and deep too, so that I was easily able to ‘place’ the instruments on the stage in Ali Farka Toure and Ry Cooder’s Talking Timbuktu album. The tonality is gorgeous here too, with the acoustic bass and shimmering slide guitar on closing track Diaraby having a rich, lush quality. The varied percussion, all delicate patted drums and ticks and tocks, had a crisp impact, but all the while sounded perfectly in balance.


3. Generous chassis dimensions result in a well-spaced rear panel with XLR/RCA in and gold-plated speaker terminals

Beating heart

The styling of Musical Fidelity’s M6x 250.7 might be nothing to write home about, but its sound performance certainly is. This is a gloriously powerful, deep-diving multichannel amplifier, but one with exemplary tonality and control too. For anyone looking to upgrade the beating heart of their cinema, it has to be considered.


10 Total Score
Recommended MUSICAL FIDELITY M6x 250.7 Review

Nothing to complain about here - behind maybe the size and weight. This seven-channel power-pusher is a superb

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POWER OUTPUT (CLAIMED):7 x 250W (4ohm, all-channels driven, 0.003% THD)
CONNECTIONS:7 x phono inputs; 7 x balanced XLR inputs; 7 x speaker terminals; 7 x phono through outputs; trigger in/out
DIMENSIONS:450(w) x 195(h) x 435mm(d)mm
FEATURES:Class A/B amplifier technology; multiple internal heatsinks; 7 x frontpanel channel status LEDs (blue = on, red = fault condition); 2 x Musical Fidelity ‘audiophile-grade’ Super Silent toroidal transformers; milled aluminium fascia; bi-amping; auto switch on


TERMINATOR GENISYS: Like every Terminator sequel outside of Judgment Day, this 2015 film has been much maligned – but that doesn’t stop it being an enjoyable popcorn ride, and one with an expansive, full-on Dolby Atmos mix on its Blu-ray and 4K releases that should be played loud and proud.

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