John Darko
UPDATE 19th February 2024: the NAD M66 video review can be watched here.
NAD’s M66 pre-amplifier (€5995) is a step apart from most pre-amplifiers. It provides gain, volume control and source selection – as most pre-amplifiers do – but the M66’s ins and outs are so numerous that it can also handle phono pre-amplification (via separated MM and MC inputs), multitudinous streaming protocols thanks to the mainboard’s BluOS module, functional expansion via a pair of MDC 2.0 upgrade card slots, D/A conversion courtesy of ESS Labs’ 9038PRO silicon (with hard-wired access via TOSLINK, coaxial and HDMI ARC), headphone amplification, subwoofer control (up to four of ’em!) and Dirac Live room compensation with Dirac Live Bass Control optionally taking over subwoofer crossover design duties from BluOS. Phew.
But the M66, as it stands right now, is not without a couple of wrinkles. It’s a Future-Fi pre-amplifier whose coin flips two ways: hardware and software. The hardware has been locked down since NAD’s initial tease at Munich High-End in May of last year but the unit’s ongoing software development pushed its shipping date from Q4 2023 to Q1 2024. Only now are proper review units beginning to roll but with a short ‘to-do’ list on the software side.
My NAD contact tells me that Roon Readiness has yet to be certified and that switching from one sample rate to another could cause a small audible pop. I sometimes (but not always) hear that pop when cutting over from Tidal’s CD-quality streaming (44.1kHz) to an HDMI ARC feed from TV (48kHz) but it’s very low-level.
To fully understand the complexity of the M66’s software development timeline, we need to remind ourselves of its key point of difference from the Dirac-loaded products previously served up by NAD.
Inside the M66, an ADC moves analogue signals arriving at its line-level and phono inputs into the digital domain ready for BluOS/Dirac processing, VU meter display virtualisation and, eventually, decoding back to analogue via the ESS DAC circuit. This is how NAD’s M33 and M10 integrateds handle all analogue signals.
However, purists rejoice (!), for the M66’s digital step is bypassable via an ‘analogue direct’ mode that puts a second version of each input inside the source selection menu i.e. Line 2 (which is the DSP-d version) and the Line 2 Analogue Bypass (which I suggest they rename to ‘Line 2 Analogue Direct’). According to NAD, a forthcoming software update will simplify access to analogue direct, which effectively means that all incoming analogue signals will remain in the analogue domain from input to output; no Dirac, no bass management, no VU meters. I already have a PS Audio BHK Signature pre-amplifier waiting in the wings for a price-appropriate all-analogue pre-amplifier comparison.
As always, any side-by-side comparisons will come from a fixed menu derived from the gear I have to hand during the review window. The M66 has already been connected via balanced XLR cables to its stablemate, the Eingentakt-loaded NAD M23 power amplifier (€3999) which in turn drives a pair of KEF R3 Meta standmounts. I have placed a single PSB BP8 subwoofer at either end of my 7m x 4m listening room to see how effectively Dirac Live Bass Control will blend their output with the KEFs.
On that, I asked NAD if the subwoofer outputs on the back of the M66 are independent. Their reply: “Yes, all four subwoofer outputs are independent, so time alignment is catered for by Dirac Live. Not only does it do time alignment but also in-band phase alignment with the other subwoofers and the main speakers. It is this that makes for a seamless integration of subwoofers with main speakers.”
The Rosson RAD-0 and Final D8000 Pro headphones paired with an RME ADI-2 DAC FS will give context to the M66’s DAC and headphone amplifier performance whilst the MC phono stage built into the Cambridge Audio Alva TT2 turntable will go side-by-side against the MC phono stage built into the M66. I’ll then wrap things up with a bow by comparing the M66 + M23 – a €10K pre-power combo – to the €11K Hegel 590 integrated.
The stage is set with the video due to land in 4 – 5 weeks, which will give NAD a little more time to iron out some of the aforementioned software quirks.
Further information: NAD
https://www.instagram.com/p/C2e_6lCtJD9/
