Review: Musical Fidelity M6x DAC – Traditional DAC

Review: Musical Fidelity M6x DAC. may seem very old-school in concept, but in reality that is not the case. It will upgrade your music system.
3.8/5 - (32 votes)

Review: Musical Fidelity M6x DACAt Musical Fidelity, after the takeover by Audio Tuning from Project owner Heinz Lichtenegger, the entire range is being renewed step by step. With respect for the past, as evidenced by the brand new M6x DAC that arrived in our test room.

The M6x DAC is the latest addition to the latest M6 generation at Musical Fidelity. It is a line that is systematically renewed, including recently with an M6 Vinyl preamplifier. The wider range of the British brand has also received many updates lately. For example, a year ago we looked at the spectacular integrated stereo amplifier M8xi of 2 x 550 Watt and 46 kg in weight. At the High End Munich Fair we also attended the announcement about the thorough refurbishment that awaits the Nu-Vista top line. In short, things are moving at British Musical Fidelity. The influence of Lichtenegger is clearly noticeable. It is striking that the acquired Musical Fidelity does not suddenly sail a radically new course. The new generation of devices neatly follows in the footsteps of previous products.

The M6x DAC that we are looking at here is really a logical successor to the M6s and the later M6sR DAC and has a price of approximately 2500 euros. In terms of technology, a big step has been taken, because the new device is a Dual Mono DAC based on DAC chips from ESS. A striking feature of this DAC is that it puts upsampling and filter selection very central. Most rivals offer similar things, but here these features have been stepped up. That gives musical connoisseurs the tools to really look for that last percent gain in terms of playback quality.

Musical Fidelity M6x

What Stereo DAC
Inputs 2 x Optical, Coaxial, USB Class B, AES/EBU
outputs cinch, XLR, 6.3 mm (headphone output)
Extras Seven digital filter, upsampling mode to 352.8 / 384 kHz
Dimensions 44 x 10 x 39 cm
Weight 6.9kg

Conservative view

Somehow we are surprised by the M6x. If you look for a traditional DAC to include in your hi-fi system, you quickly notice that the choice is relatively limited. You will find much more compact products that target the headfi market. But full-sized devices? There aren’t that many. In addition, most devices have combined DACs with streaming built in. Standalone DA converters are very rare, unless you look at expensive high-end options like MSB or dCS. Perhaps that is because you still have to provide a standalone DAC with a separate control in the form of a computer, network transport or CD transport. That only makes a bulky music system even bigger. Another box!

Yet that is exactly the path that Musical Fidelity is taking with the M6x. Like the previous M6s, this is a traditional hi-fi format device. Not only does it lack built-in streaming, it doesn’t really seem like the intention to use the M6x as a preamplifier at a power stage. Awake minds may well notice a volume control on the right side of the front panel. This is especially useful if you’re using the headphone output. Because the Musical Fidelity-DAC does have that: a better, built-in headphone amplifier. That being said, you can opt for a variable output via the XLR or cinch outputs.

So the designers of the M6x do make idiosyncratic choices. But that results in a device with specific strengths. For example, the fact that you cannot operate it with an app is something that some music lovers will not lose sleep over. There isn’t even a display. In true Musical Fidelity style, everything is indicated by means of a huge array of blue LEDs and eight buttons on the front panel. A disadvantage of this is that it is difficult to decipher that information from a few meters away. Of course it remains a DAC, not a streamer. The message conveyed by the LEDs does not change continuously.

In any case, the supplied remote lets you control everything from the listening position. It’s a big thing, by the way, with buttons with which you can also operate other MF devices. Just like with the M8xi , we found the remote control just too cheap. Certainly if we compare with the beautiful metal finish of the DAC itself. The M6x DAC is available in matte black or silver as usual. That makes it easy to match with a hi-fi amplifier from many other brands.

Also a headphone amplifier

Of course you have to combine the M6x with a digital source. As mentioned, that might be a network player or transport, so you can stream. There are many options in that area, including with sister brand Pro-ject (the Stream Box S2 Ultra, for example). Or the Primare NP5 MKII that we recently looked at or the Aries G1 from Auralic, just to give a few examples. A CD transport is another possibility. But other digital sources are also possible, such as a television.

To accommodate different scenarios, the DAC comes with different types of inputs. You can connect a computer or transport to the USB class B port. The two optical inputs and the coaxial input are useful for things like CD players. The last connection option is a digital AES/EBU port. Musical Fidelity is aiming for high-end devices with this. In turn, you can connect the DAC to an amplifier via cinch or balanced XLR cables.

Musical Fidelity M6x

More unusual for a DAC of this class is that you can also use it for your headphones. This is possible via a 6.3 mm jack at the front, with a volume control next to it. The relatively low output impedance of less than 5 Ohms gives the impression that the designers really tried to build a good headphone hatch. Even lower would be better to make it truly universal, but this will allow you to drive most hi-fi headphones appropriately. We listened for a while with a Beyerdynamic DT1990 Pro and a Sennheiser HD 650, and thought it sounded surprisingly good. Of course you don’t buy the M6x DAC for this. It is an extra, where the volume control via the remote is a nice bonus.

Musical Fidelity M6x DAC

deep roots

The most important thing with a DAC is of course what happens on the inside. Musical Fidelity does have a certain reputation in that area. And that for a long time, because already in 1987 it launched one of the first standalone DACs in the world. That Digilog was aimed at people who were looking for something better than the built-in DA converter of their CD player – a new invention at the time.

Technically, with the M6x, the manufacturer places a strong emphasis on the toroidal transformer and the output stages (the part that amplifies the analog signal coming out of the DAC). According to Musical Fidelity, a lot of work was done on the internal filtering of the power supply and a transformer was chosen that generates a small electromagnetic field. All this should ensure that the digital conversion process is not negatively affected. Internally, the M6x looks very sleek and to-the-point. There is relatively little in the housing, but that is not surprising with a DAC that is built to keep the signal lines as short as possible. The different functional areas are well separated from each other, which is very important.

Dual differential mode

As mentioned, the M6x is the successor to the M6s, one of the first DACs to implement ESS’s ESS Hyperstream II platform. The M6sR that appeared a little later was an update that brought several important tweaks. Better support for DSD, Roon support, and a different mix of inputs and outputs, among others. The M6x that we are looking at here has been technically reworked more vigorously. Musical Fidelity continues to swear by ESS, but provides the new DAC with two ES9038Q2M chips. As the ‘M’ at the end indicates, these are the mobile versions of the well-known 9038 chips. But that is not so important, because in terms of performance, the mobile editions are not hugely inferior to the desktop versions. More importantly, those two ESS-DACs are applied in a differential mode, further reducing the already modest distortion and noise. As a result, the M6x operates as a dual mono-DA converter with the two channels perfectly separated. If you connect the M6x to your (hopefully well-designed) amplifier with balanced cables, then you have a long chain that prevents interaction between the stereo channels.

We already noticed: Musical Fidelity has done its best to make it easy to experiment with the seven digital filters that the ESS-DACs are equipped with. You can quickly change filters via the remote and discover which one suits you the most while listening. At all times you can upsample the signal to the maximum. The eighth option combines upsampling to 352.8 or 384 kHz (depending on whether the source’s sampling rate is a multiple of 44.1 or 48 kHz). The difference with the general upsampling option is that option 8 bypasses the FIR filter.

Musical Fidelity M6x DAC

happy listening with Musical Fidelity M6x

After a few weeks of trying out different speakers and amplifiers, we combined the Musical Fidelity M6x with our Hegel H590 amplifier. In this case, we skip the built-in digital hatch of the Hegel and connect the Musical Fidelity DAC via XLR cables analogously. We provide a music stream to the Musical Fidelity in two ways. We connect a Zen Stream from iFi Audio to the DAC via a USB cable and we connect an AURALiC Aries LE via AES/EBU. We’re a little curious about the possible sonic difference between those two input technologies. Our curiosity does not result in a huge aha moment, but it does give the impression that the AES/EBU connection may sound a bit more pleasant. The speakers we ultimately choose are the DALI Rubicon 2’s, nice compact speakers that we like to listen to.

The Hegel H590 has a DAC part based on AKM chips. Good, but it could be even better. We have already noticed this in previous tests. We immediately get the same impression with this M6x. A very smooth, slightly soft reproduction comes in very pleasantly, with a bit of refinement extra compared to the built-in DA converter. We get an impression of more detail and insight, but not at the expense of the overall picture. There is nothing clinical about it, which only increases the pleasure of listening.

Which filter of the seven should you choose? That depends a bit on your own tastes and other parts of your music system. Also don’t expect immense differences that will suddenly provide a completely different sound. The filters provide subtle changes that we think you will notice especially in the character of the basses and very fine, high detail. We listened for a long time with filter 2 (Linear Phase Sol), but we also really liked that upsampling mode under the number 8.

We often refer to the work of Ólafur Arnalds. Perhaps because the Icelander, just like Max Richter, releases music at a furious pace that often fascinates. But also because it is also really well recorded. ‘Saman’ on ‘Sunrise Session II’ for example, is not just a tune that will make you silent. The piano is perfectly registered, and thanks to the Musical Fidelity DAC (filter 8) we have tremendous insight. It is as if we are in the Harpa Concert Hall with Arnalds, through which we also hear the many incidental sounds of his instrument, such as the hammers moving. You would hardly notice them on many systems, but here they have their own place in the whole. And that’s what makes it real. The next song, with Josin’s vocals and full-sounding strings, also comes across as particularly catchy and realistic. Here we especially note that the DAC handles source material in a very natural way. It paints a very honest picture, without emphasizing things too much.

The absolutely silent background on which the astonishing sound effects of electro pioneer Mira Calix take place during ‘a mark of resistance’ (FLAC CD quality) immediately draws our attention. The many samples and the electronic taps and beeps that are getting more and more intense and busier put the Musical Fidelity down in a very sophisticated way. It’s very easy to think of experimental music like this: “What a sound mash.” This will certainly be the case on some systems, but thanks to the good timing and detail reproduction, we do appreciate the composition. It is not chaos, but just very cleverly constructed. This ability to present music correctly and with insight is not only interesting for lovers of exotic compositions. Also ‘Halo’ by Finnish death metal stirrers Amorphis (FLAC 48/24) gets a fresh and transparent treatment. One of the positive things that comes out of this is that you better appreciate how complex and clever some metal compositions can be. In the chorus of ‘On the Dark Waters’ you can hear the contrast between the two vocal styles on every system, but thanks to that DAC (and the tight approach of De Hegel) the finesse of the fast guitar line does not disappear into the background during the chorus. . The fact that classical music has been influencing metal genres for some time is an open door – actually one is an extension of the other. So it’s not surprising that the qualities of a better DAC like this Musical Fidelity also make a bombastic crossover track like ‘My Name is Night’, with Petronella Netterhalm, come across as powerful and live. Surprising again how a component like a DA converter can do so much.

Conclusion Musical Fidelity M6x DAC

The Musical Fidelity M6x DAC may seem very old-school in concept, but that’s not to say it’s irrelevant. Are you looking for a way to upgrade your hi-fi system with a well-built DA converter that also offers you interesting filtering and upsampling possibilities? Then the Musical Fidelity M6x is one to investigate. Its no-nonsense design marries well with most audio devices. But the step it offers in terms of audio quality and commitment is certainly no nonsense, on the contrary.


  • Transparent and insightful
  • Quick access to filters and upsampling
  • many entrances
  • Headphone Amplifier

  • Leds are really very small
  • Remote could radiate a little more luxury