NuPrime, based in Los Angeles, split off from another California audio company, NuForce (Fremont). NuForce had begun in 2005 with high-end power and integrated amplifiers, such as the award-winning Reference 18 mono amp and the P-20 preamplifier, that had innovative switching power supplies that sounded exceptional -- something then virtually unheard of. Then the high-end side seemed to take a back seat, as NuForce went on to introduce $100 DACs and $500 integrated amplifiers.
In 2014, NuForce’s cofounder, Jason Lim, with backing from the OEM factory, bought the assets of NuForce’s high-end division and formed NuPrime. The new company’s first product is the IDA-16, which I first heard about from SoundStage! writer Roger Kanno. A 200Wpc integrated amp with a DSD-capable DAC? This was something I had to review.
The NuPrime IDA-16 ($2350 USD) has a clean, minimalist look very much in the tradition of NuForce’s old high-end line. The aluminum case, available in black or silver, is a low-slung, rectangular box measuring 17”W x 2.56” H x 15”D and weighing 16 pounds. It has a widely beveled front panel, along the top bevel of which are six buttons and no knobs. To the right are buttons for Volume Up, Down, and Mute. On the left, the middle, On/Off button is flanked by two Source controls, to cycle forward or back through the connected source components. Below the row of buttons, an LED on the right indicates the volume level, and LEDs on the left indicate which source is selected: U, C, C, O, O, or A, which respectively stand for USB, Coax 1, Coax 2, Optical 1, Optical 2, and Analog. On the rear panel, in addition to inputs for all of those sources, are an RS-232 port for firmware upgrades or connection to a smart home-control system, a pair of speaker binding posts, and an S/PDIF digital output.
The IDA-16’s unusual remote control has a hexagonal cross section and looks like a wand. You don’t wave it, however -- it’s a conventional IR remote. The remote replicates every button on the IDA-16’s front panel, and confirms each button press with a solid click. The only annoying thing about the remote is that, to replace the batteries, you have to undo one Phillips-head screw and four hex bolts.
Under the hood
The NuPrime IDA-16 uses NuForce’s patented Analog Switching Amplifier technology. Details of how this works are difficult to come by, let alone understand, but a glance at NuForce’s patent (US Patent 7221216) shows that it’s closely related to class-D amps, which use pulse-width modulation (PWM) to turn an analog signal into a series of pulses. This is accomplished by rapidly turning power transistors on and off. The NuPrime amp circuit improves on the class-D amp by using a “self-oscillating circuit to generate pulse width modulation.” The amplifier switches on and off at a frequency of 600kHz, well beyond the 44.1kHz sampling rate of CD. Most class-D amps switch at 300kHz or lower.
To ensure that it has enough current reserves, the IDA-16 is outfitted with a huge capacitor bank that NuPrime calls a Cross-Matrix Array (CMA). In comparison, a conventional class-AB amplifier’s power transistors are always on, and require massive transformers to be able to deliver the required current. Replacing such a linear power supply with a switching supply gives the IDA-16 an efficiency of 93%, compared to the 50-70% of typical class-AB amps. This makes possible a smaller case; because the switching power supply is much smaller and generates much less heat, big heatsinks aren’t needed. And because the NuPrime amp circuit amplifies by PWM, crossover distortion, which is inherent to class-AB amplifiers, is not a concern.
Because the IDA-16’s front end is inherently digital (the analog connection uses an A/D converter), conventional analog preamp circuitry is not needed. According to NuPrime, the consequence of this design is a shorter signal path from the digital inputs to the speaker binding posts, resulting in what the company claims are vanishingly low levels of distortion and noise. NuPrime specifies the IDA-16’s total harmonic distortion plus noise as 0.004%, which is very low indeed, though they don’t specify what power-output level or frequency band this measurement applies to. To help achieve such low distortion, the DAC chip used in the IDA-16 is a good one: the ES9018 Sabre Reference, known for its low distortion and high signal/noise ratio. Remarkably, through its USB input, the IDA-16 is compatible with not only PCM music files of up to 24-bit/384kHz, it can play DSD as well, from DSD64 (2.82MHz) up to DSD256 (11.2MHz).
Another feature of the IDA-16 is the high quality of its volume control. Using a switched-ladder array, it places only one thin-film resistor in the signal path. This further reduces distortion, and results in fine control of volume: 99 steps, in increments of 0.5dB. And matching the output levels of source components is easy with the IDA-16 -- each source’s level can be individually adjusted and set.
I found the NuPrime IDA-16 pretty simple to set up, but flawless playback did require a bit of fine tuning. I love its analog input’s handy unity gain, or Theater-Mode bypass function. I look for this in any integrated amplifier -- my system must serve both my home-theater and music-listening needs. With Theater-Mode engaged, the IDA-16 was able to drive the front speakers of my home-theater system for music-only listening, while leaving my processor to control the entire system’s volume when I watched movies. To listen to music, I turned off the HT processor and amp and used the IDA-16 for better-sounding, two-channel-only playback, without any of the processing that my HT pre-pro imposes.
The problem with the IDA-16, compared to all other HT bypass features I’ve used, is that unity gain is applied to all of its inputs. I found this out the hard way -- when I switched from this analog input to one of the NuPrime’s digital inputs, I sent a full blast of power through my speakers. Thankfully, I quickly hit the IDA-16’s Off button, and neither my speakers nor the NuPrime was damaged. This is a flaw that NuPrime should correct with a firmware update. In the meantime, I worked around it by setting the gain of the IDA-16’s analog input to the highest setting, “99.” The IDA-16 remembers such settings -- now, every time I switch back to the analog input, it’s locked at “99,” and doesn’t affect the volume settings of any of the other inputs.
You also may need to do some prep to play DSD recordings. Compared to PCM playback, DSD as a file format for distributed music is relatively new. If you’re not familiar with how to set up your system to play these files, the best thing to do is to follow NuPrime’s excellent guide, included as a PDF file on the USB thumb drive that’s shipped with the IDA-16. You’ll need to install a driver on a PC or Mac computer, then download foobar2000, a free playback software. I used my ancient 11” Acer Timeline 1810T laptop, running Windows 7; this worked fine for playing DSD files, once I’d connected my computer to the IDA-16 via USB.
I used the NuPrime IDA-16 with two pairs of speakers: my own Definitive Technology BP-8060ST floorstanders, and Focal’s Aria 906 bookshelf models, in for review. Sources were my Cambridge Audio Stream Magic 6, an Oppo BDP-85 universal Blu-ray player, and my Acer laptop.
When I first sat down to listen to the NuPrime IDA-16, two things stood out: imaging and bass control. When I listened to Rachel Z’s cover of U2’s “One,” from her album Grace (24/96 FLAC, Chesky), the imaging through the NuPrime IDA-16 and Focal Arias was astounding. This instrumental track begins with percussion to the right of the stage; then, at the center, the piano enters. With the IDA-16, the rim shots and cymbals sounded three-dimensional and rock-solid in their positions. When the piano entered, its image, too, was solidly between the speakers.
That the IDA-16 was a master of bass control was evident through the Focal Arias. These speakers sound a bit sloppy with my Integra DTA-70.1 multichannel amp, which has a class-AB, push-pull Darlington amplifier circuit. But when I played Patricia Barber’s cover of the Doors’ “Light My Fire,” from her Modern Cool (16/44.1 FLAC, Premonition/Blue Note), through the NuPrime, its power and control of the double bass and drums were remarkable. Bass notes were tight and distinct, and with each drumstroke I could feel the power through the diminutive Focals. Such bass control was also evident with my DefTech BP-8060STs, which surprised me -- I’d have thought these towers’ built-in subwoofers wouldn’t have needed any help. But with “Train Song,” from Holly Cole’s Temptation (16/44.1 FLAC, Alert), I appreciated the additional control the IDA-16 provided as it kept bassist David Piltch’s bass notes tight. To call the IDA-16 a great bass amp would be to sell it short.
Nor did it lack anything in the midrange or highs, letting the music come through unscathed. Listening to “Seductress,” from Wynton Marsalis’s Standard Time, Vol. 3: The Resolution of Romance (16/44.1 FLAC, Columbia), I heard no hardness in his trumpet -- helped, undoubtedly, by the Focal Arias’ excellent TNF tweeters. But the IDA-16 wasn’t adding or subtracting anything, either. Unlike other integrated amps I’ve used in the past, the NuPrime IDA-16 didn’t sound warm or cold -- it was as transparent as you can get for the price.
The IDA-16 was utterly quiet. NuPrime’s marketing material says that it provides “a jet-black backdrop upon which your recordings literally unfold before your ears.” Listening to “Midnight Oil,” from Gwyneth Herbert’s Ten Lives (24/48 FLAC, B&W Society of Sound), I understood what they meant. This recording of an a cappella performance is as minimalist as you can get: just Herbert’s voice, apparently unprocessed. Her performance was captivating through the IDA-16, which added no noise or anything else to distract me. At the end of the recording, as Herbert walks out of the room, I could easily follow her footsteps: to the left and out the door.
Listening to DSD tracks, I was amazed to hear how natural direct-DSD recordings could sound. I downloaded the free track from the Blue Coast Records website, which features “How Deep Is the Ocean,” performed by singer Valerie Joyce and guitarist Marco de Carvalho in a hotel suite at the California Audio Show 2014 (2.8MHz DSF, Blue Coast). The recording isn’t distinguished by stellar imaging, but it does capture the realism of the guitar, and the singer’s dynamics: she begins at a fairly low level, and gets louder toward the end of the song. These dynamic swings were easily reproduced by the IDA-16. Another DSD recording I played was “My Blue Heaven,” from Norah Jones’s Covers (2.8MHz DSF, Blue Note/Analogue Productions). Although not a native DSD recording, this track features a rock-solid aural image of Jones at the center of the soundstage, her piano spread out between the speakers and layered behind. The image of Jones’s voice seemed to float above the level of the speakers’ tweeters.
Throughout my listening sessions, I could never attribute a sonic signature to the NuPrime IDA-16, though my experience of NuForce and, now, NuPrime gear tells me that the defining characteristics of these companies’ products are transparency and a quietness that lets the music come alive. This quietness was a particular advantage when I listened at low volume levels, something I usually find uninvolving. Not through the IDA-16 -- my music was just as captivating as at high volumes. Against the NuPrime’s jet-black backgrounds, all of the dynamics of my recordings were present at all volume levels, making the IDA-16 one of the few amps I have enjoyed for late-night listening.
The NuPrime IDA-16 reminded me a lot of Bel Canto gear. A while back, I had the e.One C5i DAC-integrated amp ($1895) here for some weeks of listening. The e.One C5i’s feature set is very similar to the IDA-16’s: USB port, two coaxial digital inputs, two optical digital inputs, and an analog input and output. They differ in that the Bel Canto has a phono input. Like the NuPrime’s, the Bel Canto’s analog input can be used as an HT bypass, though its implementation is better than the NuPrime’s -- unity gain doesn’t affect the Bel Canto’s digital inputs.
The Bel Canto produced backgrounds as “black” as the NuPrime’s with music, though it wasn’t as quiet at idle. Like the IDA-16, the e.One C5i exerted excellent control over the woofer cones, which tightened up the bass response with the speakers I drove it with: MartinLogan’s Motion SLM and PSB’s Imagine Mini. Where the two integrateds mostly differed was in dynamic range -- the 60Wpc (into 8 ohms) Bel Canto was no match for the 200Wpc NuPrime. “Code Cool,” from Patricia Barber’s Smash (16/44.1 FLAC, Concord/Universal), includes wide dynamic swings: Barber sings without musical accompaniment, and then the bass, guitar, and drums all come in at once. The IDA-16 reproduced this with startling realism; the track was less dynamic through the e.One C5i, owing, in my opinion, to the latter’s lower power rating.
A final area of difference was the handling of high-resolution audio formats. The Bel Canto e.One C5i is a few years old now, and while it can play 24/192 files through its coax and optical connections, via USB it will play only up to 24/96, and it offers no direct support of DSD files -- all things that might incline you toward the NuPrime, as DSD downloads grow in popularity.
The NuPrime IDA-16 is an exemplary integrated amp-DAC with rock-solid imaging, transparent sound, and tight control of bass. It doesn’t impose a sonic signature on the sound -- I was enthralled with every recording I played through it. There are similarly priced integrated-DACs out there, from Bel Canto and Wyred 4 Sound, among others, but none offers the IDA-16’s power or support of native DSD. I highly recommend that you give the NuPrime IDA-16 a listen if you’re in the market for a modern integrated-DAC.
(1) USB Digital
(2) Coaxial Digital S/PDIF
(2) Optical Digital S/PDIF
(1) Analog Stereo RCA
(1) Optical (up to 24 bit/192 kHz)
(1) Stereo RCA (Line out)
(1) Stereo Speaker (Binding Posts) Output
USB Sampling Rates:
44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz, 192KHz, 352.8KHz, 384KHz and DSD 2.8MHz, 5.6MHz,11.2MHz
S/PDIF Sampling Rates:
44.1KHz, 48KHz, 88.2KHz, 96, 176.4KHz, 192KHz
Maximum Sampling Rate:
200W x 2 (8-Ohm)
Peak Output Power:
10Hz to 80kHz
Smart Home Control & Firmware upgrade
17 in W x 15 in D x 1.97 in H (2.56 in H include feet)
Worldwide AC voltage:
(90VAC~130VAC // 210VAC~ 250VAC) With Voltage Select Switch
Slow-blow, 5A, 250VAC
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