And you think you’re so clever and classless and free…Speaking as a peasant. I don’t like Class D amplifiers. Why?
Well, I have kept a weathered eye on the world of Class D amplifiers. And I have seen it move from being only suitable for bass speakers to something a little better, but not that much better. Following all the glowing reviews on the web I bought a pair of Nuforce power amps. We went through Version V1, V2 and V3 together and although they improved I still found the good came with bad. The good was the neutrality in the frequency response and the ability to go really loud. They could push out nearly 200w without getting hot and weighed less than Boris Johnson’s book of tact. The bad was the dynamics and the high frequencies. The dynamics were flat and not really involving. The high frequencies were really odd despite reading on the net that the high frequencies were exceptional. Yea, exceptionally bad. Real they were not. So I just went back to keeping a cynical eye on developments. Oh and wondering what some guys were drinking and where I could buy some.
All went quiet and then along comes a guy called Bruno Putzeys with a brand new breed of Class D. Last year I had a chance to hear the latest creation from Bruno Putzeys, who by that time was the new wunderkid on the Class D block. He had updated his UCD Class D amplifiers to the newer cleaner, super nCores. They are sold through Hypex amplifiers. They have bucket loads of negative feedback and a switch mode power supply, of all things. I heard the Hypex nCore NC1200 in the Merrill Veritas and the Hypex UCD 400 in the Merrill Thors. Kevin Fiske wrote up his thoughts about them on the Wam. For me, despite all the good they still had that flat and undynamic sound that did not involve me. So having tried two bites of the Class D cherry I concluded they were not for me. Hey ho….. back to the drawing board and just keeping an eye on things.
Next, guess what……a new net buzz. This time it was about the newest guy in town, Nord Amplifiers, with the recently developed Hypex nCore NC500 amplifiers. The Nord amplifiers are made in Cheltenham. Was this a case of the same old, same old??
They had brought some new USPs (unique selling points). Nord had changed the voltage regulators used in the amps from chips to discrete components, which has certainly helped Naim amplifiers, although these two amps are poles apart. Nord also introduced the ability change the Op amps from the stock LM4562 to the more expensive and better(?) Sparkos opamps or the even better Sonic Imagery 994 chips. Nord also offer Burson op amps as well if you prefer their sound. The amplifier has a socket on the main board that will take any of these opamps and all you do is plug/unplug to change the sound of your amp for the cost of an op-amp. Good idea if it works.
So I got the stereo power amplifier with the Sonic Imagery 994 op-amps. This amp produces 400w per channel at 8 ohms, 700 w at 4 ohms and about 550w at 2 ohms. A real powerhouse. As with most Class D amps it is small and light. I plugged it in and let it warm up. I use an Auralic Aries digital front end. This feeds my Audionote DAC 2.1x, a Nuforce P9 pre-amplifier and the sound comes out of my Audionote E HE Signatures. Now these speakers do not need 500w/channel (6 ohm speaker impedance) but there is no way they are going to run out of power. Oddly enough the power amps actually get warm to the touch. They only generate 40w of heat, which is channelled through to the case, so the cases do get warm. Not hot. They are still as efficient as other Class D amps.
As with most Hypex NC500 amplifiers they only accept XLR inputs (Nord can sell you a RCA/XLR cable which does the job). The connectors used are of a good quality, Switchraft XLRs and CHK for the speakers. The case is made in Italy and whilst better than the case on my Audionote preamps it is, fortunately, not expensive audio jewellery.
So the big question……..do they have all the positives of Class D and finally get rid of what for me was the big negative of a flat and undynamic sound. YES.
OK giving you some more information than that. I use a wide range of music to try out new components and a lot of it is not audiophile music which I find in most cases boring and bland.
This amplifier sounds sublime. It is very neutral, has a tremendous amount of real detail that is nicely presented and integrated into the music. The bass is deep and powerful and has great tonality where you can tell what strings are being used on a bass guitar as opposed to a boom, boom, thud, thud. It is very clear without the mid-range boost used by other amps attempting to give you detail, DETAIL, detail.
As I said I have pretty wide tastes in music and I play a lot of classical music including piano music and opera (when the wife is out as she hates it). Classical piano music is very difficult to reproduce correctly. I find the Nords are very truthful and will show when the recording is done naturally or has been messed about with mics on the lid or using ‘fill-in’ microphones.
Classical piano is not only a stringed instrument but a percussion instrument with a large wooden sounding board that can echo well in a hall. The Nords play well recorded pianos really well and maybe only miss out on a little of the weight of the piano. Although with some burn-in that improves. So for me that makes it one of the better SS amps. It can really highlight how much other SS amps mess up something simple like the frequency response or make instruments sound fuzzy and indistinct.
Pop pianos have a wide range of tones with very dry being favoured to add impact but there are very few really natural recordings. I find with a lot of SS amps that it can be difficult to tell whether the piano is real or electronic. That was less of an issue with the Nord.
I have recently really enjoyed recordings of Maria Callas and a lot of SS amps can make her powerful voice sound edgy, especially when she really lets go. The Nord rarely if ever do that. Her voice is very, very clear. It really lets you know that although she may not have been the most technically brilliant singer the emotion in her voice can on occasions be off the scale good.
When I was around at the manufacturer’s place he played Eilen Jewel’s live album. I was transported back to Texas where I was sat in a bar, having a few beers, eating peanuts and tossing the shells over the bench and really enjoying the music. What a great time. At home I had that same experience again. The music sounds very alive and the detail was easy to hear without harshness.
‘London Lights’ on Songs of Separation has the singers and the band in my room. When the backing singers came in it was easy to hear how many people were singing, with their different tonal qualities and trying to guess who had the most powerful voice. Although the bass sounds light when you first hear it, if you listen carefully the bass is there, it is very clean and very, very deep.
With live Roger Waters at an incredible volume level (empty house) the naturalness of the amp stopped the sound from becoming unbearable or shouty. The amplifiers are more truthful and some of the on-stage dynamics were outstanding. Passenger’s ‘Let Her Go’ was poignant and really sad and the amplifiers show how he changes the way he sings to emphasise what the words are saying. Some SS amps can make his voice mono- emotional. It ain’t.
Overall the problems with the previous Class D amps has mainly gone and the use of better voltage regulators and higher quality op amps has really improved the dynamics without losing the good things from the nCore amps.
If you prefer a different type of sound you can always change the op amps. I had the Sonic Imagery 994 op amp. I tried the Sparkos and they gave me a more weighty sound with a small emphasis on bass impact and a slight softening of the dynamics. Comparing the two, I would say it is down to your own personal preferences. Do you prefer Rioja or Beaujolais….?? I preferred a Beuajolais (Sonic Imagery 994) as a lighter more dynamic wine as the Rioja (Sparkos) is a little too full bodied.
Although having said that, I do like a nice Chateauneuf du Pape (Audionote). The opamps were not fully burned in so their sounds may change a bit. Whichever you prefer remember it does not cost a lot to experiment. And speaking of cost this stereo amplifier cost me £1350, which gives you an awful lot of amplifier for the cost.
I bought it at full price, £1350. Yes, Mr Dudley there was no accommodations or price reductions for good reviews here. Just a normal punter paying full price. But in the world of nCore Class D that is a cracking price.
I did pitch it against my Naim Supernait2 and whilst the Naim is meaty, beaty big and bouncy it sounds somewhat artificial compared to the neutrality of the Nord. Heresy about Salisbury but that it is what I heard.
If you get a chance, try to hear it at the Cranage North West Show if not give Colin a quick e-mail or call at Iqspeakers.
It has now become my summer amplifier as the Audionotes put out too much heat in the summer. Oh and the Krell 600 monoblocks have gone.