Naim Mu-so Second-Generation Compact Stereo System

High End Made Simple

Equipment report
Digital-to-analog converters,
Music servers and computer audio
Naim Mu-so Second-Generation Compact Stereo System

almost owned a Naim CDI player as my main source component back in the early 90s. That is more of a positive recommendation than it sounds. I did not change equipment very often, and my choice had been narrowed down to just the Naim and one other. It ended up being fortunate later that I chose the Kinergetics, as it was a more flexible platform for modifications and tweaking. However, I did feel the Naim sounded better, justifying its higher price. There was a special “Naim look” that lasted for many years, ultra-simple and clean layout and controls, with bright green display and logo. Was there also a “Naim sound”?  I can’t say definitively as the CDI was the only component I became intimately familiar with. I do remember it sounded luxurious and engaging, among other things. 

Judging from the new second generation of Naim’s extremely popular Mu-so all-in-one compact system ($1690), the new “Naim look” seems to include clean lines and an overall black/grey color scheme, as before. However, the bright green displays have been replaced by less-fun white lighting. I suppose the displays will fit into a wider variety of home décors that way. The Mu-so’s speaker grilles can be ordered in different colors: black, peacock, terracotta, or olive. As for simplicity of controls, is that even possible in an advanced, streaming all-in-one system? Yes, why not? Naim’s solution is to leave the more complex controls hidden until you choose to access them. In normal operation all you may notice is the Naim logo along the bottom front, and the large glowing circular volume control on the top. Apart from a tiny status-indicator light and a USB input on the side, the other inputs are hidden on the bottom. 

But let’s get back to what exactly this unit is: a complete all-in-one streaming compact system. From the Android or iOS apps you can stream most popular services, including Spotify and Tidal, controlled natively. You can also connect network resources and digital and analog sources directly. The Mu-so includes wireless networking, DSP, D/A converter, preamp, power amps, and stereo speakers all in one chassis. Simple, yes?

Particular Muons
Is the Mu-so 2 as small as a subatomic particle? No, it carries some heft. The ample heatsinks at the rear inspire confidence in a mountain-dweller, who has only thin air to flow over them at high altitude. Even playing at medium-loud levels for extended periods never got the heatsinks more than slightly warm. The chassis is more rigid than the original, and has 13% greater internal volume for improved bass performance. The 150MIPs of DSP power in the original Mu-so has been increased to 2000MIPs. The Class D amps have a cumulative power rating of 450W. Even the touch-wheel control interface has been redesigned, with 15 touch-sensitive points on the illuminated dial, along with a proximity sensor that wakes up the unit when you bring your hand near it. The Mu-so 2 comes with a wireless remote, and a two-year warranty, which is important since a component of such complexity would be challenging to repair, even for a professional. It would be nice to have an even longer warranty on a whole system such as this. 

Starting with the inputs, there is native support in the Naim app for Chromecast, AirPlay 2, Spotify Connect, Tidal, Internet Radio, and Roon. Of course, anything else you have on a mobile device you can send to the Mu-so 2 via Bluetooth, UPnP streaming, or USB. It also has an optical digital input, a 3.5mm analog stereo jack, an Ethernet LAN jack, and HDMI. It is multiroom-ready for use with other Naim streaming systems. I mostly listened to Tidal streaming through the Naim app (via an Android tablet) over my WLAN, though I did test the functionality of some other inputs. The others worked fine, but were not quite in the same league in sound quality.

The Naim app itself is quite well rounded, providing all the settings and controls you’ll ever need. Though it has a fairly basic look and interface, the Mu-so 2 still aims to keep as much control at your fingertips as possible. It reminded me of the BluOS app, which was a good thing, although I wish the app were available for Windows PC, as BluOS is. To be fair, the affordable Technics Ottava all-in-one units that I reviewed in Issue 300 did not have a Windows app either. Tidal navigation and music selection via a Windows app just seems faster and easier. I suppose, though, a diminutive tablet in hand is preferable to a laptop PC nearby, while you’re parked in your listening chair/sofa. However, quite often I will listen to an entire album, or at least an album side, before I move on to the next thing. (Yes, I still think in terms of album sides from time to time.)

There was a minor hiccup when trying to update the firmware of the main unit. I had paired to my WLAN and started listening to music through the Mu-so 2, when it alerted me that an update was available. I tried a few times to update it over WLAN, and the tiny light on the side changed colors, was blinking, and the volume control display was pulsing and counting-down—very exciting! From these indicators I realized that the download never completed. So I connected a LAN cable to the unit and tried the update again, and it completed successfully. This was true for both major firmware updates during my auditioning. Not a big deal, really. Just don’t waste your time attempting the update via WLAN.