Naim NAP 250DR Power Amplifier Review & Test
Full review and laboratory test of the Naim NAP 250DR Power Amplifier by Australian Hi-Fi Magazine. Free download.

The following equipment review consists of a full subjective evaluation of the  Naim NAP 250DR  but omits the technical analysis.

If you would like to read the complete review, together with a complete set of independent laboratory tests and graphs conducted by Newport Test Labs plus a full a test report written by Steve Holding, click on the graphic at the right, which is a downloadable pdf that is an exact replica of the original pages on which the review appeared in Australian Hi-Fi Magazine, January/February 2017 issue (Volume 48 Number 1).

Naim NAP 250DR Power Amplifier Review & Test

A few years ago Naim embarked on a project to produce a preamplifier and power amplifier combo that it intended to be a testament to the company’s design and engineering capabilities. The budget was unlimited, and all involved were told by Naim’s management team: ‘no holds barred, let it rip…’ The result was the Naim ‘Statement’ amplifier system which, at near $360,000 in Australian money, still stands as the pinnacle of Naim Audio’s technological expression in amplification.

But for Naim’s engineers, having manifested their greatest artistic creation, what remained? Basically, their next challenge was to trickle-down aspects of the new technology into more affordable ‘bread-and-butter’ products that would be more financially accessible not only to Naim’s ardently loyal client base, but also to new customers. Hence it is that the new Naim NAP 250DR uses exactly the same Naim-designed custom output transistors as the Statement, as well as the self-same discrete regulators (DRs) as the flagship amplifier…just not quite so many of them!

The impetus for the development of Naim’s own transistors was the company’s belief that all standard-issue transistors possess limitations in terms of power and thermal saturation that were not befitting of an all-out ‘Statement’ design. So, in conjunction with a specialist semiconductor manufacturer, Naim created its own bipolar transistors (NA009N/ NA009P), the design of which it says enables better thermal connection to the heat sink, which in turn reduces temperature fluctuations in the transistor’s silicon, and according to Naim, it’s these temperature fluctuations that cause a transistor’s characteristics to dynamically change, which is obviously an undesirable trait. The new NA009 transistors contain no ferrous materials at all: they even have pure copper legs.

In addition, the Discrete Regulator (DR) used in the flagship product now features in the NAP 250DR—as reflected by its nomenclature. As you’d guess from the word ‘discrete’, voltage regulation is achieved via the use of discrete components and the d.c. voltage reference is supplied by a 7-volt ‘buried’ zener diode, rather than a standard zener device.

The Equipment

Little needs to be said about the front panel of the Naim NAP 250DR, because it’s completely bare save for a single mains power switch at the extreme right and the little green Naim ‘bridge’ logo that glows when the amplifier is switch on. But if you look around the back of the NAP 250DR you’ll see that—and I must say ‘typically for Naim’—connectivity is…well… different. 

Firstly, only banana connectors need apply at the amp’s speaker outputs with the almost-flush sockets accepting neither spades nor bare wire. Then, there’s that lone XLR input (which almost tricked me into thinking I’d erroneously received a mono amp) that’s not actually a standard XLR socket, because pins 2 and 3 are wired ‘hot left’ and ‘hot right’ in order to facilitate stereo operation (with pin 1 as the common ground). Naim provides a connecting cable wired for this unique XLR arrangement at the amp’s end that is DIN-terminated at the preamplifier end. So, using anything other than a Naim device to ‘drive’ the NAP 250DR is not possible unless you obtain an appropriately-terminated cable to connect your preferred preamplifier’s twin output (whether RCAs or XLRs) to the single XLR input on the NAP 250DR. Irrespective of the benefits claimed for this arrangement, I find that in principle it’s… insular… and limiting. Apple anyone?

So, in order to facilitate this review the local Aust/NZ Naim distributor, NA Distributors, provided me with Naim’s Bluetooth- and App-empowered NAC-N 272 preamplifier/streamer/DAC and it was this that I used (in conjunction with the requisite DIN-XLR cable connecting it to the NAP 250DR, with all my source components in my system remaining as per reference. The NAC-N272 retails for $6,950.

The company also supplied me with an older NAP 250 power amplifier, so I could compare ‘old’ with ‘new’… so to speak. As you have no doubt guessed, the older NAP 250 continues on in the company’s product line-up, currently with a recommended retail price of $6,700.

According to Steve Sells, of Naim, there are no differences in the basic amplifier circuitry between the NAP 250 and the NAP 250DR…except that DR version has had a few component values changed to accommodate the NA009 output transistors. The power supply circuitry, on the other hand, is completely different, with Sells claiming it’s essentially a smaller version of that found in the Statement NAP S1—a highly regulated (using those discrete regulators) high-current power supply that Naim claims is ‘30 times quieter’ than the NAP 250’s power supply, and ‘maintains a more constant voltage under heavy speaker driving conditions’. 

Specs-wise, Naim specifies the NAP 250DR as having a power output of 80 watts into 8Ω loads and its frequency response as 3Hz to 50kHz –3dB. On the purely physical side, the NAP 250DR measures 87×432×314mm (HWD) and weighs 15.8kg.

Different Twins

My auditions started with the older NAP 250 amplifier in order that I could ascertain the original’s sonic signature. And yes, let me state this straight off the bat, the clichéd PRaT descriptor does apply here. The NAP 250 jumps at rhythms in a most propulsive way across the frequency range—not just in the bass response. So there’s an impression of attack and speed in the way that drums, for example, fire towards the listening seat. The snare and kick drum crisply and tightly pulse energy and establish an engaging fast rhythmic pace.

Also on offer were superb low level and overall detail retrieval, good separation of dense mix layers and an overall smooth tonality. Bass power was good—if not hat-blowing—while the NAP 250 presented excellent image accuracy laterally within a very wide—if somewhat shallow-ish—soundstage.

On an operational level, my sample NAP 250 displayed a noticeable turn-on ‘thump’ via my reference Wilson Audio speakers which, being very sensitive, tend to exaggerate such foibles. Your speakers’ sensitivity will determine the volume of the thump.

Enter the NAP 250DR. No more thump. First thumbs-up. Subsequent—and I’ll add numerous—thumbs-ups came via both subtle and not-so-subtle sonic improvements over the NAP 250. For starters, the NAP 250DR has a noticeably more dynamic presentation with contrasts in musical amplitude being both more pronounced and real-sounding. Several of my dynamics torture tests featuring well-produced drums, powerful orchestral, rock and world music recordings showed the DR in the model name could just as well stand for Dynamic Range compared to the straight NAP 250.

A surprise came via Argentinean prog-tango Sera Una Noche where the NAP 250DR showed a clean set of heels to its predecessor in the way it handled treble decay with instruments such as bells and cymbals in a number of tracks throughout this revelatory recording. The Naim NAP 250DR beautifully conveyed the harmonics and delicate detail of upper high frequencies while maintaining superb timbral signatures throughout the bandwidth.

The soundstage of the NAP 250DR is also deeper and seemingly more layered than its predecessor, whereas its width and image placement are simply on par. In my listening room there most definitely was an impression of increased distance between the vocalist and instrumentalists in live recordings, as well as an increased sense of the venue’s ambience.

The transient attack and ‘speed’ I referred to regarding the NAP 250 is maintained on the NAP 250DR. The superbly-captured snare on Like a King and Whipping Boy from Ben Harper’s ‘Welcome to the Cruel World’ snapped with terrific projection while cutting through the solid bass foundation without impinging on the clarity of Harper’s subtle vocals. Appropriate weight and emotional connection was given to Johnny Cash’s aged and deep growl on Hurt from ‘American IV: The Man Comes Around’. And although this track may seem simple enough for any competent amplifier to reproduce effectively, it’s an astutely balanced one that can produce clarity in the vocals juxtaposing the crescendo as it builds to accentuate the sentiment behind the lyrics’ message. Similar findings applied to Patty Larkin’s Winter Wind from ‘Angels Running’ where Larkin’s voice is present and floats on a platform of warm and full-bodied guitar chords.

The one consistent factor with both amplifiers but more so, to a considerable extent, in the NAP 250DR, is the connection with the music being replayed. I noticed I became immersed in the performance and relaxed into the listening experience so deeply that I found myself constantly having to make a conscious effort to don my ‘reviewer’s hat’ in order to write down these evaluations. These amplifiers invite listening and involvement.

Conclusion

Everything that Naim does it does in a distinctively individual way—and always has—from the minimalist styling that carries across all its products, to the circuitry it designs, and right down to the proprietary connectivity. To my mind, the company is making a clear statement here, which is ‘Follow us on our path and we’ll take you to the music.’ And with the NAP 250DR this is just the destination. # Edgar Kramer

Naim NAP 250DR Power Amplifier

RRP: $8,000
Warranty: Two Years
Distributor: N.A. Distributors
 

PLUS
PRaT
Dynamics
Build quality

MINUS
Connectivity
Volume control
Standby power

A full technical appraisal of the performance of the Naim NAP 250DR Power Amplifier complete with laboratory test results, frequency response graphs and an analysis of the technical performance, is contained in  the LABORATORY REPORT which is in the pdf version of this review. (Click the TEST RESULTS box).