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NAD C 328 Hybrid Digital DAC Amplifier and C 546BEE CD Player

NAD C 328 Hybrid Digital DAC Amplifier and C 546BEE CD Player

Few things in high-end audio give me greater pleasure or tempt me to more pride in our pursuit of the absolute sound than audio equipment that is both sanely priced and high performance. Under review here are two components, economically priced yet boasting excellent, even in one area quite outstanding, performance that should put paid to repeated complaints that TAS cares only about products priced for CEOs, oil barons, and hedge-fund managers. These are a Hybrid digital integrated amp and a compact disc player from NAD, a company that has few equals and no superiors when it comes to value-driven products with minimal compromise.

Ten years ago I reviewed NAD’s C 326BEE integrated amplifier and judged it not only a superb bargain but also a superb amplifier, period. It was a traditional design in the good sense, offering a built-in phonostage, several line-level inputs, balance, bass, and treble controls, a headphone amp, and 50 watts per channel of NAD power, which means that it was capable of rather large short-term voltage swings, which in turn translated into a pretty impressive dynamic range that belied its nominal power. This unit, I am happy to discover, remains in the NAD line, albeit with a V2 designation, and is still retailing for $549.

As its rather lengthy moniker suggests, the C 328, also priced at $549, is primarily addressed to audiophiles who are dedicated to all things digital, especially streaming. Despite its plain-Jane fascia and slim chassis—the C 546BEE CD player (see sidebar) is actually larger than the C 328—it offers a lot of connectivity and sophisticated circuitry with considerable engineering expertise behind them. There are three pairs of analog inputs: one curiously labeled “TV”; another “Streaming,” evidently meant for the analog outputs of a music server, though both will accept any line-level analog signal; and the third for a built-in moving-magnet phonostage. The remaining four inputs are digital: two coaxial and two optical, plus an antenna that offers Bluetooth connectivity for any suitably equipped device, including cellphones, tablets, and personal computers. The Bluetooth connection is not hi-res, but as I currently have no tuner it was nice to be able to pull up All Things Considered, TED Talks, Fresh Air, Film Week, and other NPR shows in the music room. Speaker terminals are five-way binding posts that, while hardly heavy-duty, are far more substantial than what is typical at this price point. There is also an output for a subwoofer.

Most previous NAD integrated amplifiers, including the C 326BEE, allow the amp and preamp sections to be operated independently and have balance, bass, and treble controls. These features are banished from the C 328—the loss of the balance control especially egregious (though to judge from its absence on many control units all up and down the price spectrum, this seems to bother me a lot more than it does many audiophiles). But the C 328 does sport a button called “bass boost.” NAD’s designers figured that most customers for an amplifier of this price would likely be using it with speakers that don’t exactly plumb the depths. Engaging this button boosts bass about 6–7dB at 80Hz, adding some pleasing oomph while rolling off below that frequency so as not to tax either the amplifier or the speakers with really deep bass. Though I have no use for bass boost with my speakers, the feature did provide effective loudness compensation for low-level listening.

Consistent with its digital orientation, the C 328 also contains a built-in DAC that can accept a signal from any digital component with a coaxial or optical port, including televisions, CD players, and music servers. Greg Stidsen, NAD’s Director of Technology and Product Planning, told me that the Cirrus Logic CS42528 DAC constitutes the heart of the DAC section: an eight-channel circuit that NAD implements in a “dual-differential configuration, whereby the extra six-channels are used for noise reduction and improving linearity.” Among other things, claims Stidsen, NAD is able to get approximately 10dB more dynamic range out of the Cirrus than other manufacturers who use it. Although I did most of my evaluations using the analog inputs, if your CD player is a few or more years old and has a digital output, there’s a good chance you’ll get better reproduction running it through the C 328’s DAC (see sidebar for more on this). And if you listen to your television through your stereo, as I do, and if the set has an optical output, play it through the onboard DAC for better sound as well. It should be noted that all the digital inputs are 24/192 capable.

At just under 11 pounds, the C 328 is so compact and lightweight that when I first opened the box I wondered if NAD hadn’t mistakenly sent me something other than an amplifier. The weight alone clues you that this is Class D, but that’s not the whole story. NAD calls it a hybrid amp because it licenses UcD technology from the Dutch company Hypex Electronics in such a way that the performance is claimed to come very close to that of the nCore technology, also licensed from Hypex, in NAD’s flagship amplifier, the Masters Series M22 (see Neil Gader’s review). While the Hypex technology is licensed, the output stage, designed in-house by NAD, uses different FETs and reconstruction filters for higher current levels. Rated at 50 watts per channel, the design does not permit the implementation of NAD’s time-proven soft-clipping circuit, by which its conventional amps could squeeze out somewhat more dynamic range (by in effect relaxing power-supply regulation and allowing the amplifier to distort a bit more), but Stidsen says the power supply can generate 100 watts if needed and will clip gracefully. The circuit is load invariant (hence its identical power output into four or eight ohms), and claimed to be capable of better than Class AB performance (with much lower power consumption) because the eight active discrete devices greatly reduce crossover distortion.

The principal bête noire of Class D amplifiers is the 500kHz switching frequency, which must be eliminated with a reconstruction filter. According to Stidsen, “Much like the output transformer of a tube amplifier, it can limit damping factor and cause uneven frequency response based on interaction with the impedance of the speaker being driven.” NAD locates the filter inside the feedback loop, which “gives a very high damping factor and flat response into different impedances.” More on this anon.

 

Of course, little of this new technology would matter if the performance didn’t justify it. Before I get to that, allow me to point out that I evaluated this unit exclusively in the kind of high-end system it would almost certainly never be used with in the so-called real world. The reference electronics consist of a Pass Labs X150.8 (sliding Class A, 150 watts per channel) and a Quad Stereo current dumper (140 watts per channel), the preamplifier my McIntosh C52, all feeding my reference loudspeakers, Harbeth Monitor 40.2 ($15k/pair) and Quad 2805 ESLs ($12k/pair). While neither is particularly difficult to drive, the Harbeth in fact famously benign, both are still of no more than moderate efficiency yet extremely high in resolution.

That said, I find myself in something of the same quandary as when I recently reviewed the relatively inexpensive AudioTechnica moving-magnet pickups, i.e., wondering whether I should restrain my enthusiasm if only for the sake of my credibility with the boys in the more-expensive-is-always-better club. But the truth must out: The C 328 astonished me the day I first turned it on, and astonished I remained day in, day out during the evaluation period right up to the present moment when I am writing this, not long after being bowled over by Andris Nelsons’ spectacular new recording of Shostakovich’s gigantic Fourth Symphony [DG, CD]. This sliver of an amplifier is super clean, exceptionally transparent, highly detailed, extremely low in perceived distortion and noise, and so disproportionately dynamic and stable under very demanding conditions that its size and power rating, paradoxically, soon disappeared from my mind.

Ten years ago when I reviewed the C 326BEE, one of the biggest challenges I threw at it was the third scene from Act One of Wagner’s Siegfried [Decca, CD]. This act includes the business of Siegfried chasing the dwarf Mime around the soundstage and then singing the “Forging Song” in full-throated heldentenor mode while pounding the sword Nothung into shape. The producer John Culshaw went to the trouble of obtaining an anvil and sledgehammer (as notated in the score), which the percussionist strikes in tempo while the full complement of the Vienna Philharmonic blazes all around. The sheer grip and control that this little shrimp of an amplifier, with its measly 50 watts per channel of Class D power, evinced is almost insolent. On even some really good systems, the loudest anvil strikes can for a split second obliterate the orchestra, but not with the C 328. Some audio reviewers like to make much of a component’s “timing,” that is, its ability to keep everything together. This little amplifier certainly has it. Elsewhere in the scene, the chasing about the soundstage is tracked with exemplary precision. And, no, I made no attempt during this or any of the evaluations to pamper it with levels lower than those I would normally listen at, and very often I pushed them way beyond just to hear how it would react.

As any audiophile knows, a piano is a very demanding instrument to reproduce, and the coda of the “Waldstein,” where Beethoven taxed the limits of the pianofortes of his day to actual destruction, finds the composer at his most heaven-stormingly virtuosic both as to tempo and dynamics. I put the C 328 through its paces with the Richard Goode recording [Nonesuch], and again the grip and control were little short of amazing. I also played a more recent recording of the same piece performed by Valentina Lisitsa [Naxos], hardly known for her restraint, and the C 328 once more rose to the occasion (this recording is really powerful). On the same disc is her hair-raising rendition of Liszt’s Totentanz, which the NAD dispatched with nary a hitch or hiccup.

Now I don’t necessarily evaluate an amplifier only on the strength of what it can do with the big stuff, but let’s face it, that’s typically one of the first things, if not the first thing, we want to know if we’re buying on a tight budget. And in this day and age when excellent power is cheap, 50 watts certainly qualifies as low. So once I satisfied myself on that account, I next put on Jacintha’s lovely new recording of James Taylor songs [Groove Note], and was instantly seduced, the vocal reproduction impossible to fault: seductive, rounded, dimensional, nuanced, likewise the light instrumental backups. More voices: on Joel Coen’s Sing We Noel, the choir enters from the rear and moves forward, surrounded by the resonant church acoustics, the aural impression of distance travelled from far to near was uncanny in its realism.

Both these recordings, by the way, are on vinyl, so I can verify that this phonostage is no tossed-in, let’s-give-’em-a-little-something-extra afterthought. According to Stidsen, Bjorn Erik Edvardsen, NAD’s resident genius (not too strong a word), took special pains to make the RIAA equalization very precise with a generous overload margin. I spent several pleasurable hours listening to LPs and never did the C 328 disappoint—the sound notably open, unconstricted, wide in dynamics, and extraordinarily low in noise. I suspect most buyers of this unit are into streaming and digital downloads, but this phonostage is more than good enough to cater to any users with LP collections lying dormant, or to newcomers who may want to introduce themselves to the by no means outmoded pleasures of vinyl.

The C 328 acquits itself excellently in the areas of detail, nuance, and resolution. A favorite album of mine is Gloryland [Harmonia Mundi USA], where the four women of the Anonymous Four are recorded with exceptional presence and lifelikeness. Consistent with their name, the four singers like to blend so completely as to sound effectively indistinguishable, but good systems will readily reveal the individuality of each voice, and so it was with the C 328 in place. In the Arnold Steinhardt recording of Bernstein’s sonata for clarinet [Naxos/DG], at the end of the first movement the violinist tapers off to silence. The recording is close up and vivid, and you can hear the bow moving across the string, barely touching and then tentatively letting go. Put on Martha Argerich’s stunning recording of Gaspard de la Nuit and you can hear her fingernails clicking on the keys (to the consternation of her recording engineers), while Glenn Gould’s vocalizing on his many recordings is there to annoy or be savored, according to one’s tastes. And in the coda to Bernstein’s recording of the Beethoven Ninth in Vienna [DG], you can clearly hear his foot stamping out the rhythm on the podium despite the fact that full orchestra and chorus are sounding above it.

 

Regarding tonal balance, NAD amplifiers have come a long way since the original and much-loved 3020, which had a decidedly romantic sound, warm and dark, and a little soft but always musical. A trace of this Yin character remains even in the otherwise very neutral C 326BEE, but only a trace. None of it is to be heard in the wholly neutral C 328, though I should add that on rock and driving jazz it certainly displayed a lot of punch, kick, drive, and swing. Subjectively, noise and distortion are extremely low, the presentation notable for its clarity and articulation yet without appearing in the least analytical. If this sort of hybridization is the future of Class D amplification, then I for one look forward to a time when state-of-the-art high power does not have to be housed in back-tweaking, hernia-producing chassis.

Given the potential compromises I referenced earlier as regards damping factor and thus bass control owing to the reconstruction filter, I should point out that bass response in all respects evinced no limitations that to my ears could be attributed to this filter, and once again completely belied the amplifier’s modest power output. Registration of detail, delineation of lines, clarification of textures, and sheer extension are all excellent. I was astonished—that word again!—by how powerfully the C 328 delineated the tubas in one of the more thickly scored moments in the first movement of the Shostakovich Fourth Symphony.

Before concluding, there are three aspects of this unit that I don’t like. The first is the operation of its volume control. Please note that I wrote “operation,” because the control itself is excellent, with superb tracking and a range of 120dB in 0.5dB increments, thus capable of very fine resolutions of level. The penalty is that since the volume defaults to –20dB upon turnoff (if the volume was higher than –20dB; if set lower it defaults to the previous volume setting), it takes several moments to go from very quiet to normal or louder. Second, in common with current green concerns, the unit goes into standby mode when no signal is present (I didn’t measure it, but I think the time constant is around 20 minutes). Trouble is, it takes several seconds to wake back up again and once it does, the volume remains attenuated. In either standby or turnoff, if you put in a CD and hit play, you’ll miss a few seconds of music as the level ramps up. These quirks are, however, the C 328’s default settings; fortunately, you can turn off the auto standby feature. Third and last is the remote handset, which is not much larger than a credit card and equally plastic in feel. It works, and perfectly, duplicating all the controls and more from the front panel, but it feels awfully cheesy. Maybe NAD can offer a more substantial one for extra cost. (According to the manual, the handset has a learning feature that allows non-NAD remotes to control the C 328. I didn’t test this.)

Let me grant that my high enthusiasm for the C 328 is due in part to the sheer “wow” factor of its small size/low price vis-à-vis its astonishingly big performance. To put things into perspective, I am not suggesting that lots of power and expense don’t buy you something. Of course, they do. On big stuff like the Shostakovich or Wagner, more powerful and more expensive units will sometimes bring a sense of freedom, openness, composure, and that paradoxical impression of complete grip and control and complete ease and relaxation. On very complex music, inner details, contrapuntal lines, and textures might likewise be a little easier to follow or identify, and all the lower-range instruments like doublebasses, bass drums, the big organ pipes, may register with a bit more definition and weight. And if my room were a lot bigger—it’s a little over 2500 cubic feet, 15′ x 21′ x 8’—or my speakers more inefficient, or I a headbanger desirous of much, much louder levels, no doubt the limitations of the C 328 would be more starkly revealed. But this is only to say that it cannot be expected to do what it is not designed to do, and any of these limitations would also more than likely obtain with far more expensive amplifiers of similar specification.

So those who empty their bank accounts on sound systems (or individual components!) that, as my colleague Steven Stone wrote recently, cost as much as or more than comfortable middle-class homes in many parts of the country, needn’t worry the foundations of their faith in money have been undermined or otherwise threatened by the kind of expert engineering, high performance, and sheer value that products like the C 328 embody. Still, the price differences remain so wide, the gains in performance so increasingly narrow. Such, I suppose, is the lot of the audiophile. For myself, the C 328 and the C 546BEE CD player are so good that if I absolutely had to “settle for” them, then, excepting only that missing balance control, I would feel not much deprived, and even that much I’d get over soon enough. There’s simply too much wonderful music out there to waste my time worrying about incrementals that I might be missing.

Specs & Pricing

C 328 Hybrid Digital DAC/Amplifier
Power:
50Wpc, 20Hz–20kHz at rated THD, both channels driven
THD: 0.005% at 1V output
Analog inputs: Three line level on RCA jacks, one mm phono
Digital inputs: Coaxial (x2), TosLink optical (x2), Bluetooth
Line-level output: Subwoofer out on RCA jack
Dimensions: 17 1/8″ x 21 3/16″ x 11 1/4″
Weight: 10.8 lbs.
Price: $549

NAD C 546BEE Compact Disc Player
Frequency
response: ±0.3dB 20Hz–1kHz ±0.5dB
Dimensions: 17 1/8″ x 3 9/16″ x 12 1/16″
Weight: 10.1 lbs.
Price: $549

NAD ELECTRONICS INTERNATIONAL
Pickering, Ontario, Canada
(905) 831-6555
nadelectronics.com

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