In my 20-plus years of reviewing audio equipment, I think I’ve auditioned more models from NAD than any other two brands combined. Amplifiers, tuners, CD players, receivers, and soon a turntable -- I’ve covered the waterfront with the Canada-based brand. And I’m glad. Most often, I’ve found NAD gear to be honestly designed with excellent sound quality, a lack of flash or trash “features” that do nothing to enhance one’s listening, and build quality that’s up there with some of the best budget-priced gear. I believe that NAD prices their products to be affordable for any audiophile.
So I was glad when our esteemed editor-in-chief sent the C 328 integrated amplifier-DAC my way. In July 2015 I’d reviewed NAD’s up-to-the-minute C 510 digital preamplifier-DAC, which I’d found just this side of astounding. While trickle-down economics may be a myth, the trickling down of technology does seem to happen at NAD -- the C 328 ($549 USD) offers a good array of both digital and analog capabilities.
One glance at what its maker calls the C 328 Hybrid Digital DAC Amplifier and any hi-fi fan knows it’s from NAD. It’s a long, low box in dark gray with a large black Volume knob, four small black buttons, a gold 1/4” headphone jack, and a small blue display. It measures 17.1”W x 2.75”H x 11.25”D, weighs 10.8 pounds (4.9kg), and will fit almost anywhere -- NAD says that, in use, the C 328 needs to be surrounded by only 2.5” of free space.
The front panel couldn’t be much simpler. At left is the Power/Standby button, the usual means of powering the C 328 up or down; a minuscule LED above it glows orange for Standby, blue for On. Next comes the headphone jack, and to its right are the two Source buttons (Previous/Next). At center is the display, and to the right of that are the Bass EQ button (more about this later) and that big Volume knob. The display shows which input is selected, whether Bass EQ is engaged, and the volume setting from -80dB to +12dB. The knob’s operation is continuous, and calibrated in increments of 0.5dB; going from soft to loud can take a good many spins of the knob, but that’s no big deal.
The rear panel is more fully populated, and gives a better idea of the C 328’s capabilities. At left is a connector for a Bluetooth antenna; below that are two optical (TosLink) digital input jacks, then two coaxial digital jacks (RCA). All digital inputs are 24-bit/192kHz capable. Next are the RCA jacks for the three analog inputs: Streaming, TV, and Phono. Yes, Virginia, a phono input, suitable for moving-magnet or moving-iron cartridges! That’s followed by a single RCA jack, which sends audio signals below 100Hz to a connected subwoofer. Next to the subwoofer output is a ground terminal for your turntable, and above it an RS-232 connector for connection to a system controller from AMX or Crestron.
The central third of the rear panel is occupied by two pairs of speaker connectors that can take bare wire, large spade lugs, or, if you pry out the EU/UK-required blocks, banana plugs. At far right is a three-pronged inlet for the IEC power cord (included). Finally, there’s the main power rocker switch. With that flipped to On, the Standby/On switch on the front can be used to turn the C 328 on or off in daily use.
The C 328 offers several features not readily apparent if you haven’t read the owner’s manual, and that must be selected and activated by the user. Auto Standby returns the amp to Standby mode when it doesn’t sense a signal for 20 minutes. In fact, there are two Standby modes. In the first, Eco, the C 328 draws only about 0.5W and can be roused only by pushing the Standby switch, or by playing a Bluetooth source or a connected app. In the other Standby mode, Control, the C 328 uses about 2W, but there are many more ways to turn it back on: play a Bluetooth source or connected app; rotate the Volume knob, or either of the remote control’s Volume Up/Down buttons; press the Bass EQ or either Source button; or press the front-panel Standby button or the remote’s On button. The Auto Sense mode powers up the amplifier if a signal is detected at any of its inputs, analog or digital.
Though the C 328’s remote control is about the smallest I’ve seen, at only 3.5” x 1.5”, it duplicates the front-panel controls and adds several more. Starting at the top and working down, there are first two buttons, for On and Off. Below these are Up and Down buttons for Source and Volume, and between them a Mute button. A bit farther down are the display’s Dim button (three levels, from very pale to blinding, plus Off), and one for toggling the Bass EQ on and off. At bottom are three buttons to control playback from a Bluetooth-connected device, from left to right: Previous, Play, Next.
If you have another, non-NAD remote, the C 328’s remote can teach it NAD’s command codes. The owner’s manual describes in detail how to do this.
Speaking of the manual, it’s certainly a product of the 21st century, discussing in more detail the C 328’s digital features than the connection of the analog inputs and outputs. I’m not complaining -- the sections on Bluetooth and the various digital connections, and the many aspects of the remote, etc., are covered very clearly and are most helpful. NAD’s warranty is of the usual, limited variety, covering defective parts plus labor for two years.
The C 328’s output is specified as 50Wpc into 4 or 8 ohms. Signal/noise ratios of -95dB (analog line-level and digital inputs) and -75dB (MM cartridge) indicate that the C 328 should produce negligible background noise. From analog line input through speaker output, the total harmonic distortion claimed is no more than 0.03% throughout the audioband, at any power level from 100mW to 40W. The frequency response is 20Hz-20kHz, ±0.3dB.
I wondered why NAD has gone with Hypex UcD-based class-D circuitry in many of their newer products. Greg Stidsen, the company’s director of technology and product planning, had this answer:
The philosophy that created those technologies has never changed at NAD, though new technology allows new solutions. We think that an amplifier should be able to drive a real loudspeaker with a music signal without distortion. This has led to a focus on dynamic power and high current capability. We call this “PowerDrive.” In the C 328, we enhance this capability by inverting one channel to gain unused power supply capacity. In a small power amplifier like the C 328, this can make a noticeable improvement in sound at the upper limit. Class D is still developing and has further scope for development even though we are close to a “perfect” amplifier now. We use two technologies that were only concepts just a few years ago; Direct Digital Feedback and a self-oscillating analog switching amplifier we call Hybrid Digital. The C 328 uses Hybrid Digital amplifier technology.
NAD’s promotional materials are skimpy on details of the Bass EQ. In fact, all they say is that engaging Bass EQ “boosts overall bass response by at least 6dB.” The C 328 will probably often be used with very small speakers, and some sort of bass enhancement is a valuable offering. “Bass EQ is a High Q filter centered at 80Hz with an 8dB boost,” Stidsen told me. “This gives the typical 5 1/4” vented bookshelf two-way just what it needs to sound big and dynamic. Because it attenuates subsonic frequencies these small speakers can’t reproduce, it also reduces distortion at high volume levels.”
Bass EQ is the only tone-modification control offered -- the C 328 has no balance, bass, or treble controls. For me, this is a mixed blessing; I use tone or balance controls rarely, but I do like having the option of using them.
All in all, the C 328 is a tidy little package. I did wonder, as it contains a DAC, why a USB input was excluded. It seems as if one could have been added -- perhaps at the expense of a coaxial or optical input -- because it would have made the amplifier even better suited to a wide range of users (my DAC uses USB). “USB requires both hardware and software to process whatever functionality is included and that all costs money,” Stidsen told me. “Also, since USB was never intended as a high performance audio interface extra cost is incurred making it behave for audio. . . . [I]t is just a matter getting the right mix of features, performance, and price.”
As mentioned, the C 328 is small, especially in terms of height. Usually, such amplifiers require some vertical space, if only to give their heatsinks room to dissipate the heat generated by the output transistors. The C 328 apparently had no such need -- after several hours’ use at moderate to high volume levels, its case was barely warm.
In general, the C 328’s sound will be familiar to anyone who’s had experience with NAD gear: neutral, detailed, crisp, and, at first listen, lean -- no blowsy bass or fat midrange. In fact, I found that, with my Electro-Voice Interface 1 Series II speakers, I wanted the boost the Bass EQ button adds; the E-Vs do a fine job overall, but need some help with oomph.
The C 328 excelled at detail. From deepest bass to highest highs, the level of detail in its reproduction of recordings was exceptional, especially with more delicate-sounding instruments such as flutes, violins, and brushed cymbals. The precision with which instruments and human voices were reproduced was outstanding. And, overall, the channel separation was amazing. With some old, crudely mixed stereo recordings -- half of the band panned hard left, the other half hard right, the singer dead center -- the C 328’s output was almost scarily discrete, with no discernible crosstalk between channels. That held for all inputs, analog or digital.
I first concentrated on the C 328’s phono input, using it with the Pioneer PL-516 turntable and Nagaoka MP-110 cartridge, a combination I’ve recently written about. The Nagaoka traversed the rapid singing of the four vocalists in “Four Brothers” and “Birdland,” each with words by the late Jon Hendricks, from The Best of the Manhattan Transfer (LP, Atlantic LP SD10319). The cartridge did a fine job, but I wouldn’t have known that had the NAD not done its job so well. It responded instantaneously to any signal with a sound that was fast and precise as it reproduced the incredibly rapid singing in both tracks. In short, the C 328’s phono input sounded darned good.
Other LP cuts, such as “50 Ways to Leave Your Lover,” from Paul Simon’s Still Crazy After All These Years (Columbia PC 33540), and “You’re No Good,” from Linda Ronstadt’s Heart Like a Wheel (Capitol LP ST-11358), also impressed -- the former for the snap of the snare drums, the latter for the width and depth of the soundstage, plus the sustain of the violins at the end. The balance of the sound produced by the C 328 was really fine.
I then tried an optical (TosLink) input, to which I connected my Sangean HDT-1x AM/FM/HD radio tuner. I’m a big fan of HD Radio, which usually provides unique niche programming on its HD-2 channels. My local favorite is the 24/7 Jazz programming on the HD-2 signal of our local classical public-radio outlet, WGUC. The stream has a fairly wide digital bandwidth, so in my opinion it’s high fidelity. The C 328’s reproduction of WGUC’s service was as good as I’ve experienced from an HD-2 channel with any amplifier.
I took advantage of the C 328’s second optical input to connect my Sony CDP-X303ES CD player, to compare the sounds of the Sony’s digital and analog outputs. The Sony’s analog output is variable, so I could match levels. I tried a variety of musical genres. Recently, I’ve been getting into the sound of vibes: Milt Jackson of the Modern Jazz Quartet; Victor Feldman and Cal Tjader, from the 1950s and ’60s; Gary Burton, of more recent times; and Steve Hobbs. I heard Hobbs in concert in Raleigh, North Carolina, in 2005, bought his Spring Cycle (CD, Random Choice RCD-21), and have been enjoying it ever since. Track 1, “Blued Spring,” was a nice start to my listening session. Hobbs’s vibes were right up front, the backing instruments -- piano, trumpet, tenor sax, flute, bass, drums, percussion -- spread out behind. Through both of the Sony’s outputs the C 328 sounded very neutral, very linear, and very clean, with fast attacks and releases -- no smear. I kept thinking that the sound was “pure.” To my amazement, the digital side was slightly “rounder” -- slightly fuller in the lower mids -- than the analog output, which had more prominent upper mids.
Next was Gary Burton with the theme song to the TV show Frasier, “Tossed Salad and Scrambled Eggs,” from Swinging Jazz for Hipsters, Vol.2 (CD, Concord Jazz CCD-4791-2). This was an all-star lineup of players: Burton on vibes; John Scofield, guitar; Fred Hersch, piano; John Patitucci, bass; and Peter Erskine, drums. The recording engineer had some fun with this cut -- whoever is soloing is right down front in the middle, the other instruments respectfully farther back. Burton’s vibes tone in this cut was fabulous as reproduced by the NAD, while the piano was exceptional -- precise, melodic, and full. The digital side again had a slightly fuller lower-midrange sound.
After this, I wanted something that would push the limits of the Sony’s analog stage. I pulled out Diane Schuur & The Count Basie Orchestra (CD, GRP GRD-9550) and played “I Just Found Out About Love.” Schuur’s voice is marvelous, with an incredible range, and when she cuts loose in her highest register it can cause my Sony’s analog stage to stagger a bit. That was less the case with the C 328, but on the digital side there was no strain whatsoever. Throughout this cut, the Basie band is nothing less than brilliant: taut trombones well in the background, walking bass not prominent but still anchoring everything. It was a very coherent sound by the NAD -- very impressive!
Thinking a digression into classical might be instructive, I put on Hoedown, from Aaron Copland’s ballet Rodeo, with the Baltimore Symphony Orchestra conducted by my favorite maestro, David Zinman (CD, Argo 440 639-2). The NAD’s Bass EQ circuit helped fill out the sound at anything less than lease-breaking levels. The instruments of the BSO were beautifully layered from front to back, and attacks and articulation were well-nigh perfect. The piano sounded lively, as it should. The overall sound was a bit lean, but overall, I think the C 328 is a great amp for orchestral music. In this case, the music sounded slightly purer through the Sony’s digital output.
Copland led me to his stylistic opposite, Leopold Stokowski, who often arranged works by baroque and classical composers as full-tilt, postromantic extravaganzas. I chose one from Erich Kunzel and the Cincinnati Pops’ The Fantastic Stokowski (CD, Telarc CD-80338): Stoki’s arrangement of J.S. Bach’s “Little” Fugue in G Minor. It begins with a lone oboe; gradually, the rest of the orchestra joins in, until the piece ends in an earth-shattering finale featuring the famous, almost outlandishly bombastic Telarc orchestral bass drum. The difference in sound between Baltimore’s Meyerhoff Hall and Cincinnati’s Music Hall has never been so clear to me as here. While the BSO’s sound was very definitely layered from front to back, that of the Cincinnati Pops was more muddled, not nearly so distinct. Stokowski’s arrangement was still mighty enjoyable, and the climax at the end was thrilling, but the Meyerhoff recording offered a cleaner sound. The C 328 clearly laid out the difference between them.
I then tried the Cambridge Audio Azur 651C CD player that normally resides in my main system, to hear how the C 328 would sound via its coaxial digital input. I heard little if any difference between the sound of the Azur 650c’s analog and coaxial digital outputs. This was especially true with Jimmie Lunceford’s “Rhythm Is Our Business,” performed by guitarist John Pizzarelli and the Don Sebesky Big Band on their Our Love Is Here to Stay (CD, RCA Victor 67501-2). This is a busy, up-tempo performance, with lots going on between Pizzarelli’s nimble fingering and the band’s chops. There was almost no difference in sound between the Cambridge Audio’s digital and analog outputs, which told me that both were very well engineered. Everything was rife with detail, in a precise sound that had me stomping my feet.
Due to its features and power output, I thought the C 328 would be a great match for the amplifier in my secondary system, the Onkyo A-9010 integrated amplifier-DAC, my review of which appeared on this site in March 2016. The two amps’ power outputs into 8 ohms are very similar: 50Wpc for the NAD, 44Wpc for the Onkyo. The Onkyo has only one coax and one optical digital input, vs. two of each for the NAD. The Onkyo has four line-level analog inputs, the NAD three. The Onkyo A-9010 offers bass, treble, and balance controls; the C 328 doesn’t. Both have MM/MI phono inputs. Both have a bass-boost circuit, while the Onkyo’s Direct mode bypasses the tone and balance controls. And at $349, the Onkyo costs $200 less than the NAD. When I reviewed the A-9010, I found it to have fine, coherent sound with excellent detail, not to mention its being a screaming great deal at its price. Since then, nothing has changed those opinions.
For this comparison, I used the NAD’s coaxial digital input, my Cambridge Audio Azur 651C CD player, and the title track of Pizzarelli and the Sebesky Big Band’s Our Love Is Here to Stay. In this very clever and amazing chart, Pizzarelli plays and sings “Our Love . . .” while the band plays Count Basie’s “Li’l Darlin’” -- the two tunes work together perfectly. There wasn’t much difference in the sounds of the Onkyo A-9010 and the NAD C 328. Both reproduced this recording crisply and precisely. I liked them equally.
I tried the same comparison using the CD player’s analog outputs. Here again, I liked both amps, but it was nearly a tossup. After several more comparisons, I concluded that the Onkyo sounded very slightly more full, but that the NAD may have been more accurate. Here’s hoping you’ll be able to listen to both and come to your own conclusions.
Tonally, the two amps were quite similar, though in the A-9010 Onkyo sticks with their Wide-Range Amplifier Technology (WRAT) version of the traditional class-AB circuit, and the NAD is class-D. I felt the need to switch in the Onkyo’s Loudness and the NAD’s Bass EQ circuits, for a bit more robust bass response from my E-V speakers.
After one marathon listening session, I went to bed but couldn’t sleep, buzzed by what I’d been hearing all evening. The Onkyo A-9010 is a champ of an amp, but the C 328 won by a decision in the 15th round. The Onkyo has a $200 price advantage, but there are reasons: a more traditional (though fine) amplifier stage and fewer digital inputs. In its favor are its bass, treble, and balance controls. I like it a lot and will no doubt continue to enjoy it.
But something about the NAD C 328’s sound amazed and mystified me. I kept coming back to the descriptor pure. Its sound was clean and sleek. At first listen it seemed a bit reticent in the bass, but recordings of any bass power belied that impression. I could hear no background hash. In fact, the C 328’s sound reminded me most of that of NAD’s C 510 digital preamp-DAC: Backgrounds were simply “black” with no fuzz -- zero, zip, nothing, nada. Very impressive -- even the phono stage was unusually quiet. As much as I admire the Onkyo A-9010 for its being a heck of a value, the NAD C 328 beat it in terms of pure music reproduction.
The C 328 isn’t fancy. It follows the NAD tradition of no flash, no glitz, just solid performance. If you’re not someone who fiddles with tone controls, if your listening room is of reasonable size and your speakers are of at least moderate sensitivity, I recommend the NAD C 328. It’s a superb integrated amplifier-DAC.
. . . Thom Moon
- Sources -- Pioneer PL-516 belt-drive turntable with captive phono cable, Nagaoka MP-110 cartridge; Cambridge Audio Azur 651C, Sony CDP-X303ES CD players; Sangean HDT-1x AM/FM/HD radio tuner
- Integrated amplifier-DAC -- Onkyo A-9010
- Speakers -- Electro-Voice Interface 1 Series II on Sanus Basic 24” stands
- Interconnects -- Dayton Audio analog; Belkin, Dayton Audio, Transparent Audio digital
- Speaker cables -- Acoustic Research 14-gauge
NAD C 328 Integrated Amplifier-DAC
Price: $549 USD.
Warranty: Two years parts and labor.
NAD Electronics International
633 Granite Court
Pickering, Ontario L1W 3K1
Phone: (905) 831-6555
Fax: (905) 837-6357