REVIEW: Mutec MC-3+ USB: clocking the best way to improve your digital audio

German pro-audio company proves that, for the best possible sound, timing is everything

That’s the problem with being interested in audio: just when you think you have your system completely sorted, along comes something to challenge your assumptions and show you there’s still room for improvement. The problem is doubled (at least) when you make a substantial part of your living reviewing hi-fi equipment: not only is one’s system less like the much-vaunted open window into recordings, and more like a revolving door, but it’s also necessary to confront the ‘different, but is it better?’ question on an almost-daily basis.

(Actually, trying to make a living reviewing hi-fi equipment is a problem in itself, but that’s a horse of a different colour.)

Mutec MC-3+ USB

Just occasionally, however, something comes along to change one’s parameters by causing a re-think of assumptions, and that’s the case with the Mutec MC-3+ USB, a little black (or silver) box with a battery of lights, made by a German company specialising in pro-audio equipment but just beginning to find itself a niche in the wider audio market.

I’d been hearing good things about the Mutec from several sources I tend to trust simply because their listening tastes and experience tend to accord with mine, so I was interested to take a listen and find out for myself what all the fuss was about. I have to admit to a certain cynicism, not to mention a feeling of ‘do I really need another black box in my system? I thought this digital audio stuff was meant to make life simple’, but the plainish-looking white shipping box sat around in my listening room while the non-stop procession of products for review came and went, daring me to give its contents a try. Eventually I could ignore it no longer, and into my system it went.

You might by now have got that there wasn’t a whole lot of feverish anticipation going on – after all, how much difference could yet another tweak make? I’d already bought a dedicated computer to play audio files, configured it with almost everything not sound-related turned off and plugged in a couple of Audioquest Jitterbugs – was it worth doing anything else?

Indeed, was it worth introducing another component, at around £800 costing more than many a high-quality DAC, into the system, especially when I’ve always been quite an advocate of ‘less is more’, keeping signal paths as short as possible, and so on?

And anyway, what’s this Mutec thing supposed to do, when it’s at home?

Time for an explanation
Well, the MC-3+ USB is the latest in a range of products from a company for which timing is almost everything: based in Berlin, Mutec makes a range of clock generation and distribution devices, plus sample rate and format converters, used in professional audio and video applications.

Put simply, all digital signals need to be referenced against a master clock – a kind of ultra-high-speed electronic metronome use to keep things in order – and if the master clock in your digital source is singing from a different hymn-sheet to that being used by your digital to analogue converter, problems can arise in the way digits get crunched into audio. Well, I did say ‘put simply’…

The result is jitter, perhaps most apparent in video systems, where it can sometimes be seen as a slight flicker in the monitored image, but also capable of subtle effects on audio, such as a loss of definition, or in extreme cases clicks and pops.

Mutec MC-3_plus_USB_alu_Closeup_B_RGB

For that reason, the optimal solution is to get all the devices in a digital chain taking their timing from the same master clock, which is what Mutec’s reference clock generators and distributors do. And what the MC-3+ USB does, in a mains-powered box just under 20cm wide and a little over 4cm tall, is ‘reclock’ an incoming digital using a high-precision clock signal and then output it to whichever DAC you choose to use with it.

Actually, it does rather more than that: the Mutec doesn’t just tidy up the digital data, but rather uses what the manufacturer describes as ‘aggressive’ re-clocking, stripping all the clock data from the incoming signal and replacing it with the output from its own high-precision internal clock. Or, in a studio environment, it can share that clock signal with other devices with clock inputs, so everything is kept in sync, or accept an input from an external clock generator.

Mutec MC-3+ USB

Of more interest to the audio enthusiast will probably be the ability of the Mutec to take a variety of digital input connections – USB, optical and coaxial S/PDIF and AES/EBU – and output them via almost as wide a range of connections, after doing its reclocking stuff.

Conversion, too
It also offers format conversion, being able to accept inputs all the way up to DSD256 – which uses a sample rate of 11.2MHz – and output at up to 176.4kHz, doing the DSD-to-PCM conversion on the way. Mutec points out that what’s happening here isn’t a sampling rate conversion – avoiding that was a major element of the design – but rather ‘a direct down-dividing out of the DSD stream, respective to its embedded sampling rate’.

In other words, it will convert from DSD down to 176.4kHz, 88.2kHz or even 44.1 kHz (if you must), but not to 192kHz, 86kHz or 48kHz as these wouldn’t be a direct step down in sampling rate.

Meanwhile the USB-B input has full galvanic isolation, meaning no electrical noise from a connected computer can get through it to the connected DAC.

Mutec MC-3+ USB

Not surprisingly, this comprehensive capability, and the pro-audio origins of the unit, means that – although it only has two buttons to control it, a third being no more than a power switch – the Mutec can initially look baffling. That’s in no small part due to the 33 LED indicators crammed into that compact front panel, along with a lot of tiny labelling. But then the specification means there’s a lot to cover on a product with very little frontage and a job title like ‘Synchronizable Digital Audio Master Clock and Audio Re-Clocker and USB Interface’!

However, once you get the hang of the operation – there’s a menu selector and a button to scroll through the options – it doesn’t take long to set up the MC3+ USB, and once chosen you can clock in your settings against prying fingers attracted by all those glowing lights. Or indeed you can turn off all the lights should you find them distracting, allowing the Mutec to be used in what’s effectively ‘stealth mode’. Believe you me, you will find them distracting.

So (deep breath), does it work? The simple answer is yes, and with every single device with which I’ve tested it. In the past few months I’ve had through my room a bewildering variety of DACs, from those built into a number of integrated amplifiers all the way up to big-ticket non-oversampling audiophile models, and in every case the Mutec has brought sonic gains which are immediately apparent, from cleaner detail in even the subtlest nuances of recordings through to a tighter sense of rhythm and timing, and – my personal favourite – enhanced presence.

In other words, recordings played from the MacMini using Audirvana+, which is my go-to set-up for DAC testing and increasing amounts of my listening, simply sound more real. It’s not a subtle improvement, even with relatively inexpensive DACs such as those built into some sensibly-priced amplifiers, it appears to be consistent across a wide range of recordings, and I’m yet to find a DAC whose performance doesn’t benefit from the inclusion of the Mutec in the chain.

And of course it also has the not inconsiderable benefit of enabling you to use your computer’s USB output with DACs only providing conventional S/PDIF inputs. Used with the Naim DAC, for example, it turns an already very fine digital-to-analogue converter into what is, by any standards, an exceptional USB DAC.

In fact, I’d go so far as to say that, with most DACs offering direct USB input of DSD data – usually in the form of DSD over PCM frames, or DoP – the sound of the same files via the Mutec’s onboard conversion, output to the DAC as 176.4kHz/24-bit over coaxial digital, has greater impact and vibrancy, along with an improved sense of ‘rightness’.

UPDATE 29.07.16: With the latest firmware, v1.10, which was launched by Mutec on July 28th – I’ve had an early copy for a little while now – the MC3+ USB makes an even more confident contribution to the sound of a system. There’s better detail resolution, crisper timing and more punch than with the previous iteration – and the effect is especially noticeable when playing DSD files, for which there’s now auto-detection to make the MC-3+ USB even simpler to use. Existing owners can download the new firmware here.

Mutec MC-3+ USB

Of course as a reviewing tool the MC-3+ USB is slightly problematic, as it can mask some of the deficiencies of a DAC under test running ‘under its own steam’. But as a way of revealing what else is happening in the audio chain it’s proving invaluable: it forms a very potent digital audio combination with an inexpensive MacMini and the Naim DAC in particular and, as I discovered in some recent listening sessions, starts to throw some new light on the effect of even small changes in the components used to feed it with digital data.

But perhaps that’s a story for another time…

The Mutec MC-3+ USB is available through UK distributor Affinity Audio.

Written by Andrew Everard


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