HiFi-Plus 65: NAD M4 Masters Series AM-FM-DAB Tuner

Integrated amplifiers,
Digital-to-analog converters
NAD Master Series M4
HiFi-Plus 65: NAD M4 Masters Series AM-FM-DAB Tuner

High-end tuners are thin on the ground. I suspect it’s the influence of DAB, because it didn’t used to be like this. Not so very long ago, Accuphase, Linn, Naim, Day Sequerra and Magnum Dynalab all had seriously no-compromise tuners on sale. Until recently, that list dropped to just Accuphase and Magnum Dynalab, but surprisingly NAD has changed all that.

The company’s new £1,438 M4 arguably completes the brand’s Masters Series – its top end, built like a tank range of audio and home cinema electronics. The M4 is a combination DAB and AM/FM affair, designed to fit snugly into a system comprising M3 dual mono integrated amp and M5 stereo CD/SACD player. As a consequence, with its grey on silver livery and steel case, the tuner is one of the biggest, most hard-looking tuners around – only the aforementioned Magnum Dynalab from Canada does ‘butch’ better.

The controls are exactly as you might expect from a NAD Masters. Simple, to the point, with a multi-way controller (think the controller on the back of a Canon camera) an array of seven buttons beneath the blue scrolling dot-matrix display, and one solitary power buttons on the opposite panel. The rear panel shows just how flexible this tuner is; no combi aerial connector here – there’s a separate connection for AM (two spring clips), FM and DAB (75-ohm coax connectors). There’s also digital coaxial and optical outputs for those who want to hook the M4 to a DAC, a pair of gold phono connectors and an array of trigger and RS232 hook-ups for custom installers. And yes, you can beef up the mains lead if you want, because it has a two-pin IEC connector. Okay, no balanced outputs (both the M3 and M5 sport XLR links), but this represents about as good as it gets in the crazy, wacky world of audiophile tuners today, from a connectivity standing at least.

This is matched by a M4 remote, which neatly clones the features and functionality of the front panel, with the added bonus of glowy buttons for late night listening. And, like the rest of the tuner behaves, it itself extremely well. No hiccoughs in moving from band to band, storing presets is easy and quick and the display can easily turn its hand to the usual variety of informational activities (except some of the more traffic-oriented subroutines of RDS). This sounds like a natural function of any good tuner, but experience shows that as you go up the price band so occasionally the tuner gets quirky. None of that here; no three finger power chord to switch from FM to DAB, no defaulting to Latvian in the set-up routine, no turning the power on and off just to get into ‘preset’ mode. It is even undemanding of FM signal feed – so many posh FM tuners demand the best possible signal, but here the FM sound hits stereo and is quiet with even the humble copper Model T supplied with the majority of tuners. In other words, this is as easy to operate as any good budget tuner, and is all the better for that.

NAD has been canny with this tuner. In many respects, it’s similar to more budget models in the range (like the C445) sharing as it does tuner front ends, which takes advantage of the common functionality and operational control. This is because there’s no need to reinvent the wheel… You just make a better class of wheel. So, higher spec chips and a IF stage with three ceramic filters have been specified in the FM tuner stage, while the DAB section has a higher grade of shielding and a very acceptable Burr Brown DAC (coupled with op-amps from the same chip fabber) that wouldn’t look out of place in a CD player in the signal path. Speaking of clever, the same chassis is used in the US as well, this time replacing the DB-1 DAB module with an XM satellite radio head. Common once again to all the NAD Masters range, the tuner has a seriously beefy power supply in the box; overkill in a tuner, but falls under the ‘if a job’s worth doing…’ remit deployed throughout high-end audio.

In the interest of completeness, AM radio through the M4 is, well, pretty dreadful, just like AM radio routinely sounds when mistakenly amplified through a stereo system. The M4 tries to make the best of a (very) bad job, by seeming to eliminate some of the worst hiss, but as the only surviving reason for AM replay is cricket coverage and that’s largely solved by DAB, it would have been no great omission. Still, at least it’s good to have it there in times of national emergency.

FM is a much better served. It offers both a useful ‘blend’ mode to knock out some hiss from fringe stations by making a station not-quite-mono at the high frequencies, and it has tighter tuning steps (12.5kHz) than most from its shielded MOSFET RF stage. This is a godsend in a metropolis, as a nasty sideband from a pirate house music station used to butt in over BBC Radio 3 at regular intervals, and TheToday Programme is not improved by having a Soca backbeat.

For stations untrammelled by pirates, the FM sound is remarkably noise free and extremely well-balanced in frequency response, entirely without the plague of multipath adding enharmonic distortion to the treble. Multipath distortion must still be there – no-one’s knocked down all those buildings between my house and the nearest mast – but is effectively suppressed better than many on this tuner.

The rare product that bests the NAD (Magnum Dynalab springs to mind again) does so by taking the next step in tuner thoroughness, rolling its own tuner head. This is a considerably more costly implementation than simply buying an off-the-shelf tuner head as MAD has done. The improvement can be likened to the difference between an Armani Black Label suit and something made for you by a Savile Row tailor; the custom-made route is a better ‘fit’ for the rest of the tuner circuit and makes a big difference to those who notice these things. Specifically, it’s this ‘roll your own’ approach that moves you out of the listening room and into the studio with the Eddie Mair, or knee deep in silage with Eddie Grundy. You don’t get that level of detail on the NAD, but this detail is at the sharp end of the 95% rule, though and unless you gain an awful lot of pleasure listening to radio on a very regular basis with an extremely good aerial, the custom tuner head may not prove the draw it might first seem. Certainly, if the choice came down to either a NAD M4 as it stands, a rudimentary version with a more expensive tuner head or a £5,000 version with the best possible FM stage, most would go with NAD’s current offering.

DAB is somewhat harder to suss out, given the variable quality of bit rate on offer. It is perceptibly louder than FM in this model, and that built-in DAC upgrade did appear to bestow a significant benefit on the M4’s digital radio output. The sound had considerably better separation and a more open midrange on anything at 128kbps and beyond and even 96kbps mono talk radio was mercifully free from the chestiness that seems to trouble male voices on DAB. The sound of the on-board DAC was as good that of the M4 and a separate DAC, so there seems to be no point in aftermarket upgrades; cheaper DAB devices sometimes need a good DAC, so that’s less of a saving in comparison.

It pains me to say this, but I suspect DAB imposes its own price ceiling in audio quality terms, and this was something that doesn’t happen with analogue FM radio. And that price ceiling happened several hundred pounds below the price of the M4. So those expecting a huge jump in DAB sound quality between this and the entry-level DAB tuners will be disappointed. In DAB sound quality alone, the M4 is better than cheaper models, but not as significantly as the price might imply.

This is not NAD’s fault, though and the M4 raises the bar for FM replay on a DAB tuner, which is going to be a major source of quality audio for at least the next decade. And that’s a major feather in the M4’s cap – it represents the perfect transition product, from excellent FM to great DAB. And it’s well-built enough to live out the last years of FM… However long that ends up being.

Technical Specifications

 NAD M4 Masters Series Tuner
Type: AM/FM/DAB tuner

FM Tuner Section
Capture ratio (FM): 3dB
Image Rejection: 85dB
Signal/Noise (mono): 72dB
Signal/Noise (stereo): 66dB
IF Rejection: 78dB
Channel separation @1kHz: 42 dB
Frequency response: ±1.5dB (20Hz-15kHz) ±1.0dB

AM Tuner Section
Usable sensitivity: 30dBµ
Selectivity: 17dB
Image Rejection: 28dB
IF Rejection: 36dB
Signal/Noise Ratio: 38dB
Harmonic Distortion: 3%

DAB Tuner Section
Tuning Range (Band III): 174MHz-240MHz
Tuning Range (L Band): 1452-1492MHz
Sensitivity Range Band III: -100dBm typical
Sensitivity Range L Band:-97dBm typical
Signal/Noise: 100dB
Frequency Response: ±0.3dB

Dimensions (W×H×D): 435x100x300mm
Net Weight: 8.97kg
Price: £1,438


NAD Electronics
Net: www.nadelectronics.com


Armour HE
Tel: +44 (0) 1279 501111

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