Class D is gaining a good deal of momentum in the audio world. Lionel Payne listens to the the Nord One UP NC500 DMST stereo power amplifier costing £1409.
The Nord One UP power amplifier is the brainchild of Cheltenham based designer Colin North and designed around the Hypex nCore NC500 modules. Built within a three-quarter width all aluminium case, this Class D power amplifier is a true dual mono design. The 10mm front panel is available in standard black or silver, or for a relatively small cost premium, numerous exotic veneered finishes are available. Mine arrived with a very attractive American Black veneer which I felt easily warranted the small surcharge. There is a solitary on/off button to the front fascia which is surrounded by a blue LED light and to each side of this are three parallel grooves. Above the power button lies the Nord logo badge. Around the back are solid brass gold-plated quality binding posts for 4mm banana plugs, spades or bare wire (up to 8mm) as well as an IEC socket, an on/off switch and XLR sockets (note : no RCA inputs here). The Nord One UP can deliver up to 400watts per channel at 8ohms resistance, 700watts at 4ohms and 550watts at 2ohms and despite the Class D generation of amplifiers being renowned for their efficiency and low running costs this power amplifier does run a little warmer than one would expect. However, the casework is well designed and allows airflow through vents on the bottom as well as the top panel. New casework has been announced.
When I first received the Nord One UP it was in Revision B form and came to me with Burson V5 and Sparkos Labs SS3602 as alternative op-amps. These op-amps are interchangeable internally through an eight pin DIP socket and it takes literally a few minutes maximum to change over. I found the Burson op-amp very similar to my old feelings of Class D amplifiers; all being rather cold and clinical affairs , albeit with a fabulous tonality. I’m pleased to say that none of the old feelings arose when listening through the Sparkos op-amps as I now found the music took on an all new feeling of tremendous organic quality. A sound I have to say that really impressed me, particularly given the asking price.
A short time after receiving the amp I happened to bump into Colin North at a hifi show in the Midlands, and we had a good discussion about his product. He explained to me that the product’s design was still evolving and he had discovered an even better op-amp but unfortunately it was adding unwanted noise to the circuit. He explained that he felt the voltage regulation board was at fault and was working on improvements to make the circuit silent with this new op-amp. I suggested, if possible, that I would love to hear this new version of the product when he had cured its teething problems. A short time later the Nord was sent back to Cheltenham and returned to me in Revision C form with an upgraded (and, I’m told, more costly) voltage regulator with the new Sonic Imagery 994 op-amps installed. Colin had promised a similar sound but with more air around instruments and a much better soundstage with the trade-off being a slightly less fulsome bass response that the Sparkos op-amps could provide.
On being re-acquainted with the Nord One UP I immediately found that the soundstage had, indeed, improved with Revision C and the Sonic Imagery 994 op-amps (pictured above). Playing Sting’s “Live In Berlin” disc through the Acoustic Precision Eikos CD player resulted in startling imagery as well as superb tonality and timing. I went on to play quite a few of my favourite and most well-known CD’s back to back. I loved the air around instruments and the 3D soundstage which was so much better than I remembered but something kept tugging at my consciousness to tell me something was missing, and try as I might, I didn’t immediately recognise the missing element. The amplifier appeared to be playing music with the same qualities it had shown before – namely, a superb tonality with great dynamics and a wonderful ability to shift scale and weight with tremendous athleticism. Crescendos are replayed with fabulous enthusiasm with the Nord. Listening to Nick Cave’s “Red Right Hand” caught me out one time as it followed a quietish acoustic track on my playlist and the opening bell on the track had me jumping out of my skin !
Unfortunately, when the amplifier was returned to me, the inclusion of the Sparkos Labs op-amps had been over-looked and I was left to ponder whether the missing element was linked to the Sonic Imagery op-amps. I contacted Colin for the Sparkos to be sent over and within a few tracks after swapping the op-amps I finally recognised the difference. To my ears, and your opinion may vary from mine, the difference was almost completely visceral. The Sonic Imagery op-amps are very good and I’m sure some will find that they prefer them in their system. However, I found the Sparkos op-amps to be more organic in quality and they would draw me far deeper into the emotion of the music. There is a little more fullness to the lower regions with the Sparkos but it’s far from a chalk and cheese situation. In fact I found the Sonic Imagery to be perfectly acceptable in all areas of the sound spectrum, but emotionally I was drawn in by the Sparkos. This may be a result in my favoured genres of music that I prefer to listen to, as I prefer a good amount of acoustic material mixed mainly with Indie and rock music, although my overall collection is extremely eclectic.
I have to admit that this review has been quite a prolonged one, and that is partly due to how much I have enjoyed the Nord One UP within my system. It also proved to be a godsend as my own trusty Musical Fidelity Tri Vista 300 integrated amplifier blew a channel during the review period. This required an extensive repair (my grateful thanks to John Sampson of jsaudiorepairs.co.uk for a fantastic job) but while I had the Nord One UP I was never left wanting for more. In fact, as it is a very even-handed, neutral sounding amplifier it proved an invaluable asset during it’s time as my substitute reference.
Having this power amplifier within my system for so long has certainly allowed me plenty of time to analyse its strengths and weaknesses. I have also used it to drive a fair few pairs of loudspeakers, not all of them an easy drive, and I have to say it has proven to have the grip of an Olympic shot-putter on steroids ! It drove Shahanian Obelisks with ease and also, when partnered with PMC FB1+’s delivered a soundscape better than any other amplifier I had ever tried with them.
However, having superb grip and drive is not the only strength of this power amplifier. When subtle is required, the Nord delivers with equal control and finesse. As previously stated it also has a wonderful control of differing dynamics within a mix and delivers crescendos with superb precision. I used even-handed as a description earlier in this review and that is exactly what you get with the Nord. To reveal any weaknesses is a difficult proposition as I feel it has none at all, and at this price point must resemble extremely good value for money. Another selling point is the opportunity to try different op-amps which can tailor the sound to your tastes. It is even an economical amplifier in use, using far less electricity than most other amplifiers with this quality.
What’s not to like? If you are looking for a new power amplifier in this area of expense, get this one on your audition list!
Even-handed with all types of music
Sound can be tailored with differing op-amps
Powerful with frugal running costs
Fantastic grip for even difficult loads
Nothing at all at this price
Good with well laid out internals
Can sound a little clinical in some systems but the op-amps will help
Wonderful even-handed presentation in the right system
Value For Money:
An astonishing price of £1409 this power amplifier represents a true bargain buy
- Two Hypex NCore NC500 Module
- Two Hypex SMPS1200A700 Power Supply
- Two Nord One UP Input Buffer Board Choice of Sparkos SS3602 or Sonic Imagery 994 Op Amps
- True Dual Mono Design
- Distortion: THD+N – – 0.001 % 20Hz
- Frequency Response: 0 – 50k Hz +0/-3dB
- Low Distortion: THD+N – – 0.001 % 20Hz
- High Input Impedance 51K
- 26 dB Gain
- Ultra High Damping Factor
- High Current 28A Output capable of driving 2ohm
- Frequency Response: 0 – 50k Hz +0/-3dB
- Case W 340mm D 280mm H 90mm
With Feet and Binding Posts W340mm D340mm H95mm
Idle power 36W