There are no two ways about it: Musical Fidelity’s M8xi is a beast. The integrated amplifier dwarfs most competitors in terms of size, weighing a vertebrae-crushing 46kg. Perhaps the most astonishing fact is that it has a massive claimed power output of 550 watts per channel in 8 ohms, which then jumps to a dizzying 870 watts as the speaker impedance is cut in half.

The M8xi is a slap in the face to everyone who thinks an integrated amp is a poor substitute for a pre/power combo. Inside the massive frame of the Musical Fidelity – 16 x 44 x 40cm (hwd), in case you were wondering – is a very modular design, with the DAC, preamp, and two monobloc power amplifiers isolated as much as possible by the casework.

Musical Fidelity M8xi:Specs

  • Power Output 550W per-channel (8Ω), 870W (4Ω), Peak 1.6kW (2Ω)
  • THD (+noise) <0.004% typical, 20Hz to 20 kHz (XLR)
  • Signal to Noise Ratio > 86dB ‘A’-weighted (XLR)
  • Frequency Response +0 , -1dB, 10Hz to 100 kHz
  • Inputs 4x RCA, 2x XLR, 2x coax S/PDIF, 2x optical S/PDIF, USB type-B Asynchronous
  • Outputs 1x RCA fixed, 1x pre-out RCA variable, 1x XLR variable, 1x coax S/PDIF, 1x optical S/PDIF
  • Dimensions (hwd) 184 x 483 x 510mm
  • Weight 46kg

Musical Fidelity M8xi Build

This Musical Fidelity is a well-made unit with a high level of quality. We like how simple its main controls are, albeit the display could be a touch bigger to make it easier to read from a distance or at an angle. Inside, you’ll discover two large toroidal mains transformers, and clear care has been made to avoid interactions between the product’s numerous analogue and digital circuitry. It’s not as well-organized or physically appealing as the interiors of high-end devices, but that’s not a concern as long as it works properly and reliably. The M8xi also runs hot, thus ventilation becomes an issue if overheating isn’t a concern.

There’s a lot of interconnection here. The digital-to-analogue component is built around the Texas Instruments PCM5242 DAC chip and features five inputs (USB type-B, two coaxes, and two optical) as well as two digital outputs (optical and coax).

Those who value specifications are unlikely to be impressed by the Musical Fidelity’s rather limited 24-bit/192kHz resolution limit through USB and coax. The optical input, as is customary, reduces that to 24-bit/96kHz. It’s not difficult to find low-cost outboard DACs that easily outperform the M8xi’s resolution restrictions while also supporting DSD. Having said that, we don’t believe this will be a deal-breaker for most consumers; this system will still play the vast majority of music files accessible.

There are two sets of balanced XLR line-level inputs, as well as four single-ended RCA inputs for analogue fans. There are both balanced and single-ended preamp-out options, though we’re not sure why anyone would feel the need for additional power. A single-ended line-out and a switchable ‘AUX 2’ input that can be programmed to bypass the M8xi’s preamp section and feed directly into its muscular power amp circuitry round out the list.

It’s surprising that Musical Fidelity didn’t include a phono stage in this design, given such a circuit has become increasingly popular in recent high-end integrated we’ve evaluated. There is also no headphone jack.

Of course, outboard components can be used to provide a phono stage as well as headphone driving capability, but that’s not the idea. After all, one of the benefits of integrated amplifiers is that they contain everything in a single package, thus removing such capabilities makes less sense in this context.

Musical Fidelity M8xi Sound

Any amplifier at this level requires a high-end system to shine. As sources, we use our standard Naim ND555/555 PS DR music steamer and Technics SL-1000R record player. Because the M8xi lacks a phono stage, Vertere’s award-winning Phono-1 is used. On the other end of the signal chain, we have our standard ATC SCM50 speakers, as well as a set of Dynaudio Confidence 20 and a pair of ProAc Response D2R, to see how the M8xi performs with other speakers.

Given the amplifier’s massive power output, it’s no wonder that it drives all three speaker options with ease and achieves massive volume levels with remarkable restraint. We rarely hear an integrated sounding so controlled and unstressed at this level.

We’re also excited about what all that power implies for the bass. Listening to Massive Attack’s underappreciated Heligoland set, we’re struck by the M8xi’s low-frequency grip and authority. When the music demands it, it kicks powerfully, but it also delivers the notes with quickness rather than droning on. Normally, such a powerful amplifier would lack rhythmic force, but not here – the Musical Fidelity delivers Atlas Air with both determination and energy.

It also has a solid midrange. This area is clean, crisp, and well-rendered with a lot of detail. Even when the music is loud, the voices are clear and easy to follow. This isn’t the amplifier to buy if you’re looking for the ultimate in texture and finesse – there isn’t quite the dexterity for that – but we believe the M8xi will satisfy all but the most critical listeners in these areas.

When we switch to Mahler’s Symphony No.2, this sonic beast seems totally at home. It has a huge soundstage that is both spacious and well-focused. It’s an open and stable presentation, with instruments held in place and never swaying, even when the song becomes demanding.

Given the Musical Fidelity’s power reserves, it’s odd that dynamics aren’t superb. They are, indeed. This amplifier hammers out large-scale dynamic swings with elegance while simultaneously communicating nuances with finesse.

There’s a lot of information here, as well as the capacity to hunt down low-level musical strands without losing sight of the big picture. The M8xi is an exciting listen with appropriate music that delivers all of the drama contained within the original performance.

Tonally, things are even enough to produce convincing results on a variety of instruments. If an M8xi sounds bright and harsh in the higher frequencies, it hasn’t had enough time to warm up properly or is mismatched with the speakers. After a few days of use, our sample appears to be fairly balanced.

We experiment with the amplifier’s digital inputs and are satisfied with the results. Despite the subpar specifications, this is a good-sounding digital module that’s on pace with some of the top three-figure outboard DACs on the market. We utilise a MacBook (equipped with Audirvana playing software and tonnes of high-resolution music) and a Cyrus CDi CD player as digital sources and find the M8xi to be delightfully consistent across inputs, despite the varying quality of the sources.

The sound of the amplifier retains the vibrant and exciting nature of the analogue line stages, which is more than can be said for many of the built-in DACs we typically encounter. We listen to a wide range of music, from Bruce Springsteen and Miles Davis to Eminem, and the M8xi never disappoints, reproducing the sound with energy, understanding, and a physicality that is quite appealing.


  • Entertaining presentation combining muscularity and clarity
  • Huge power output
  • Good onboard DAC


  • Huge and heavy
  • Runs warm
  • No phono stage or headphone output

Musical Fidelity M8xi Conclusion

The M8xi has a lot of power, and it shows in its strong and powerful demeanour. Throw pretty much anything at this amp and it will never appear out of its depth, but beneath all that muscle is a product with enough emotional reach to gratify across a wide range of musical genres. The Musical Fidelity M8xi is unquestionably on the shortlist.