[Review] Hypex DLCP and NC400 listening test

Hypex DLCP processor and NC400 amp modules

Product: DLCP and NC400
Manufacturer: Hypex - The Netherlands
Cost: DLCP 275€, power supply 40€, add-on boards 175€, NC400 325€, SMPS600 180€, Soft start module 40€, XLR to XLR cable 75cm: 130€ (all prices ex. vat)
Reviewer: Maarten van Casteren - TNT UK
Reviewed: October, 2014

Hypex is an innovative Dutch company, located in the city of Groningen. They produce a whole range of products, but are most famous for their class D amplifier modules. Hypex have a great reputation in the business and could be considered a sort of "manufacturer's manufacturer".

When I visited Max Townshend last year and he demonstrated his fantastic reference system to me, I was very surprised to find Hypex UcD amplifier modules in there. Max did tell me that he was using them with his own linear power supply, but still there's no doubt that Hypex is being used in some of the best systems in the world, and several rather expensive high-end amplifiers are in fact simply based on Hypex modules. Even some of the latest NAD digital amplification was developed in collaboration with Hypex. These guys really know what they are doing, that much is clear.

So, when a manufacturer like this announces that they are introducing a new range of improved amplifier modules, it should get our attention. The new NCore class D amplifiers are said to be superior to the existing UcD amps, which have been reviewed here on TNT very positively before. The NCore modules are said to have extremely low distortion and noise into loads as low as 2 ohms. The NC400 modules in my review sample can produce 400 watt, but that's in 4 ohm. It is probably more realistic to call these 200 watt amplifiers, but then again: they can actually produce almost 600 watt into 2 ohm! And on top of that they even have a damping factor of almost 1000 into that 2 ohm load, at 20 kHz! You won't find many amps with the specs of these modules, believe me. The promise, therefore, is technically perfect sound. Not all audiophiles are after that, but I personally cannot think of one single reason why.

To supply power to the NC400 module Hypex make a dedicated, audio quality 600W switch mode power supply, the SMPS600. This comes complete with all cables needed to connect it to the NC400. As the NC400 actually has on-board overload and error protection you can build your own power amp using just one power supply board and one NC400 per channel. This combination is explicitly aimed at DIY amp builders, and not at commercial users. Lucky us.

I have actually reviewed another Hypex product before: the rather nice AS2.100 digitally active loudspeaker modules. I liked these very much, even though they weren't perfect. Well, Hypex have recently also released DLCP, the Digital Loudspeaker Correction Platform, a DSP module that can be used to create a completely digital active 3-way stereo system. They claim it is much better and more flexible than the AS2.100 module, so that sounded very interesting to me.

The DLCP features digital and analogue inputs, volume control, 6 independent output channels, full DSP filtering on all outputs and can be fully controlled and configured from a PC through a USB connection. It really is difficult to imagine something you cannot do with the DLCP, but the main purpose of the unit is obviously to create a digital active 3-way stereo loudspeaker system, with the additional option of doing some basic room correction as well. You just need a digital or analogue source and 6 channels of amplification.

What would happen, I couldn't help asking myself, if these two components came together? Use the DLCP module to digitally split the signal for a 3-way stereo system and use 6 NCore amplifier modules to actively drive the speakers. That would make an interesting system! Active crossovers and more than a kilowatt of total power, all of that in Hypex quality, that's the stuff of dreams! Until they offered precisely that to me for review! I couldn't believe it.

To be completely honest, it was also a bit daunting. Creating a fully active 3-way system is complicated and should be left to specialists. I am not a specialist. But a system like the DLCP is making this a lot easier than a traditional passive crossover, and even easier than an electronic crossover. In theory, this should all be quite flexible, and I'd had some experience with the AS2.100 modules already, so this should be doable, I hoped.

Luckily, a friend of mine had a pair of XTZ 99.38 speakers that I could borrow. These are 3-way and feature an external crossover, so didn't need any modification to be used with the DLCP / NCore combination. The 99.38 use a Fountek Neo CD3.0 ribbon tweeter, 150mm Seas Excel mid and 225mm Vifa bass units in a massively built cabinet, so they are perfect for the job.

In use

What I received is actually a custom built solution to be able to test the DLCP and NC400 units: Hypex only sell these as separate components, so if you'd like to try them out, you will have to buy the bits and put them in a case yourself. This is strictly DIY.

The DLCP is housed in a case that makes it look very much like a simple preamp, with a display and a few buttons at the front, and a lot of connectors at the back. Actually, apart from the DLCP itself this case also contains two add-on component: one that has the display and the buttons and is designed to sit in the front and communicate with the user, including a receiver for the remote control, and another input board that sits in the back of the case and includes all the input and output connectors. Building a complete DLCP machine means putting these add-ons in the front and back, putting a DLCP in the middle, adding a power supply and hooking it all up with the provided cables. Again, like the NC400 amps, this is totally aimed at the DIY audiophile.

The DLCP is not an example of excellent ergonomics, I have to admit. There are 4 main buttons to operate it: one pair to select the function, and another pair to execute it. So, you can chose to either change the source or change the volume. If you try to turn up the volume while you are still in source selection mode then the source will change, not the volume. I didn't like it very much, especially as the remote initially only managed to control the execution part, and not the function selection bit, before it stopped working altogether which then turned out to be a configuration mistake I made in the filter software.

The DLCP is also not the most family friendly solution, as it requires a little bit of knowledge and care to be operated correctly. This really is a system for enthusiasts and basically unsuited for general use, at least in its present form. Having said that, it really wouldn't take much to change that, and Hypex have told me that they are working on new software so all this could improve in the near future.

The amp box is much simpler: 6 XLR inputs, 6 loudspeaker outputs and a mains power connector. It doesn't contain a power supply for each individual NC400 module: there are 6 amp modules and only 4 power supplies. This means that 4 of the 6 NC400 modules have to share a power supply, while the remaining 2 have their own dedicated SMPS600 unit. Obviously, I used the 2 individually powered amps for the bass drivers, while the other ones were connected to the mid and high drivers.

The amplifier also contains a soft start module and this was configures such that the power amp would switch on, softly, when the DLCP was activated. This requires a trigger cable between both components.

Hypex also included 3 pairs of their own XLR interconnects to hook the DLCP up to the power amp. Their cables seem very well made and feature good quality Neutrik XLR connectors. They are a pleasure to work with, as they are more flexible than most high-end cables. Hypex claim very good, double shielding and extremely low microphonics for their cables, which should make them very quiet. Sound wise I didn't notice any difference when I compared them to my own Van den Hul XLR interconnects, or the longer XLR leads that I had made to hook up my active speakers. This is as it should be, as my own cables are also of excellent quality. Perhaps the Hypex cables will give a specific advantage in a noisier (electric and acoustic) environment, but I didn't have a way of checking this. They're not cheap, but still offer reasonably good value in the current climate where cables can cost more than a decent CD player, I suppose.

The sound, NC400 amplifier

Let's start with the amps. For stereo purposes I obviously used the 2 channels with the dedicated SMPS600 power supplies. I was lucky to still have the Magnepan 1.7 speakers that were on review. These are very revealing and quite demanding of amplification, so excellent for testing a top quality amp like the Hypex. The NC400's like to be driven in balanced mode, so the source was always my OPPO BDP-105 Blu-Ray player in variable volume output mode. This is a high quality balanced source and doesn't require a preamp.

First, for comparison, I tried the M1.7 speakers with my own Usher R1.5 amplifier. The Usher is a real muscle amp and has great dynamic range and magnificent bass. I have always liked it very much, and was not disappointed: it made the Magnepan panels sound great. Typically, the bass was strong and very well controlled and the whole presentation effortless, with an enormous sound stage and excellent dynamic expression. Listening to this combination you cannot help thinking that not much more is possible. It simply sounds fantastic.

But then I hooked up the Hypex amps. I was surprised at how much better the sound became - really surprised. The clearest, most immediately noticeable improvement is in the top end. The Hypex simply exposes the Usher as having a bit of an edge. With the NC400 modules doing the driving, the Maggies sounded much cleaner, sweeter, more open and more precise. The last time I had a top end like this was when I still owned a valve amp, but that amp didn't really do bass. The Hypex do sound a little bit dryer than the Usher, but bass is still nothing short of excellent, with better definition and texture than the Usher. In some respects it almost sounds like going from a passive loudspeaker to one with an active crossover. There's simply more clarity, more control, more precision.

In a way, the NC400s sound almost undramatic, as very soon you forget about the amplifier at all. It does its job, and it does it very well, but without drawing any attention to itself. There's no added richness, or increased perceived detail. No extra warmth to the bass, no over-sharpened focus, no showing off or other tricks. Just plain, honest amplification that lets the music pass through as it is.

Make no mistake: it is certainly not the case that you don't realise this is a powerful amp, in full control of the speakers, but it does it so effortlessly that you stop noticing and simply listen straight through it. This, obviously, does not come at the cost of enjoyment: it's just that you'll be enjoying the music, and not the system. At least that's what happened to me. And, no, they certainly do not sound analytic.

Actually the difference between these two amps simply sounds like the removal of the Usher. The Hypex NC400 more or less takes the amp out of the equation, simply adding power to the signal and nothing else. Hypex claim these amps add neither dirt nor fairy dust, and I couldn't agree more. To me this sounds like nothing is added, and nothing is taken away. If you then realise that you can build a stereo pair of Hypex amps for 3/4 of the price of the Usher you start to appreciate how special these modules are. Then have a good look at the packaging: the Usher weights over 40 kilos, while you can pick up a stereo amp based on the Hypex modules with one hand. The Usher consumes 280W when just switched on, and still over 60W when switched off. The Hypex consumes a tiny fraction of this. There simply is no comparison. And do not think, not even for one moment, that this is because the Usher is a bad amp. I went through a dozen power amps before I settled on the Usher, and for no other reason than that it was the best sounding one of the bunch. It has a tremendous reputation, and I have always loved it to bits, but I now find it outclassed by these Hypex NCore amplifiers. It's not that the Hypex amps play circles around it, but they do sound better, are easier to live with and cost significantly less than the Usher. For me that adds up to a pretty conclusive win.

This also is more or less the first time that I've had a power amp in my system where I'm struggling to describe how it sounds, and I'm having even more difficulty finding any sort of flaw or shortcoming. I've reviewed quite a few power amps before, and I've always come away thinking if only I could have the bottom end of this one with the top end of that one and the dynamic expression of yet another one. In the end you choose the compromise that suits you best. I don't have that feeling with the NC400's. It feels more like problem solved. They actually sound like the bottom end of a transistor muscle amp, the top end of a valve amp and the dynamic expression of a class-A amp: effortless, flawless and totally enjoyable.

Then there's compatibility. The NC400 modules are very powerful, can drive any load and are as clean and neutral as an amp can get. They accept single ended as well as balanced inputs, although mine only had the balanced ones, which are preferred by Hypes. But the datasheet explains in great detail how to also get the best out of single ended sources. All of this this means that there will not be many occasions where they won't fit in perfectly. Buy a pair of these amp modules, and the next time you upgrade your speakers you will not have to worry about your amplifier.

The sound, DLCP

The DLCP is a different kettle of fish. First of all, the documentation states that you can use it as a digital preamp on its own. It does have both analogue and digital inputs and volume control, so this is true. It was the first thing I tried, mostly because it was the simplest way of using it, but also because it would give me a good idea of its qualities as a DAC. The result was slightly disappointing: it didn't come close to my modified OPPO BDP-105 player, which also has digital volume control. Compared to the OPPO the DLCP sounded somewhat grainy and flat. It's also not very ergonomic, which doesn't help. Even though I cannot deny that it will function as a DAC/preamp, I cannot recommend it for such use. Better solutions are available for this sort of money.

But this is no problem, obviously, as although you can use it as a digital preamp, it is not intended for that, but to be the heart of digital active speaker system instead. For that you need the dedicated software, which will allow you to completely control and configure the DLCP module on your Windows PC. It needs to be connected by means of a USB cable for that. I'm sorry to have to say that the ergonomics of the software are not better than those of the DLCP itself. And the documentation isn't very good either.

In spite of all that I did manage to get it working with the XTZ 99.38 speakers. The first problem is getting good measurements. Without precise measurements it is totally impossible to define the correct settings for the digital crossovers and the other filtering you might want to apply. Luckily Hypex had been nice enough to include a measurement microphone for me, but even with that I soon found out that making a really good measurement is not as easy as I thought. The Hypex software includes the functionality to make the recording, and to correctly truncate it so that you are only using the non-echoic part of the measurement. But I found that even small changes in the setup can make big changes in the measurement. It took me quite a while before I had some measurements that seemed OK.

Once you have reached that point then setting up the crossovers is not very difficult. But, of course, most drivers need a bit more filtering than just the crossover, and even if the crossover itself might be easy to specify, that doesn't mean that it is easy to know what crossover frequency to use, and what steepness. There's a reason this is done by experienced design teams in most loudspeaker manufacturers.

One big advantage of digital crossovers is that you are able to delay the signal for each driver. In passive crossover design it is often very difficult to correct phase differences between the tweeter and the midrange driver. In many cases the polarity of the tweeter is reversed to improve things, but this is obviously a very crude way to address the problem. With the DLCP you can phase-align your drivers perfectly, and this is undoubtedly on of the biggest advantages of a digital system.

Of course, with all the filtering power of the DLCP at your disposal it becomes relatively easy to also correct some of your room problems. Basically you can tailor the sound of your speakers completely to the environment they are used in, and to your own taste.

It took me a long time, but in the end I did manage to set the system up in a way that measured and sounded quite good. The end result is great clarity and precision, combined with almost limitless dynamic possibilities. The resulting system has all the properties of a good active system, in other words. My biggest problem with the Hypex AS2.100 modules I reviewed before was the stereo image, which I found to be poor. The DLCP/NC400 combination doesn't suffer from this at all.

Actually, the only minor shortcoming to speak of was a tendency to sound a little bit uninspired. Obviously you can tune the system to sound any way you like with the digital filtering, but I still found it difficult to remove that last bit of analytical presentation. Perhaps I am simply too much used to nice sounding systems to be able to appreciate the truth anymore. In any way, it really is a minor problem, as the DLCP / NC400 / XTZ 99.38 combination sounded very good indeed. Deep articulated bass, extremely transparent midrange and crystal clear top end make for a very engaging and insightful listening experience.

Initially I was worrying that it wouldn't sound very good because of my experiences with the DLCP as a preamp, but quite clearly that was no problem at all in the final setup. The advantages of having a completely digitally optimised active system seem to more than compensate for the less-than-high-end DACs in the DLCP. Actually, the complete system sounded pretty much as good as I've experienced in my room.

So, given that I liked the end result, what was my problem then? Well, I wasn't really able to do much more than specify the crossover points and put in the main filters to implements these crossovers. I also made the three drivers the same level and was able to delay the tweeter relative to the midrange driver. That's all fine, but this was all in simulation mode within the software and I didn't manage to do the necessary measurements of the system as a whole to verify that it all behaved as it should. I also wasn't able to compensate for any possible room problems, or solve any other problems with the cabinets or the drivers.

Ideally, a digital DSP system should allow you to do all this, but the Hypex software becomes quite unreliable when you try to do anything but the most basic things. Luckily, Hypex know this, and are in the process of rewriting the control software. A new version should be much better, but sadly it will be a while before it will be available.

In the end, the main thing that kept nagging me was the fact that I was simply never completely sure if it was all set up correctly, or hadn't lost its settings since the last time I used it. The software and the DLCP itself simple do not feel stable enough to make you confident that it's all as it should be. And when you are hooking up an amp that can produce over 600W directly to a fragile tweeter, that's not a good feeling. It certainly didn't add to my listening experience, no matter how well it worked otherwise.

Conclusion

My opinion of the NC400 amplifiers, used with the SMPS600 power supplies is very simple: these are the best amps I've used to date and offer unbelievable value for money. They are powerful, easy to live with and are the closest approximation of 'a straight wire with gain' that I've yet encountered. They have the top end and midrange of a very good valve amp and the bottom end of a powerful transistor amp. I've always loved my Usher R1.5, but the Hypex modules simply outclass it. If you are looking for a good power amplifier and don't mind a bit of DIY then you just have to have a look at the Hypex NCore amps. I don't think anything can beat them at their price, and I seriously don't think any amp can be much better at any price.

The DLCP is a different story. It is a fascinating product, and one that I was very excited about, but the harsh reality is that building a digital active system is much more complicated than I thought, and the DLCP suffers from a few software and ergonomic problem that make the task even more complicated. If you are willing to invest a lot of time and effort then I can only recommend the DLCP unit, as you can actually build a great sounding system with it, but for most people it would not make much sense. Hypex are in the process of rewriting the software, though, so things might improve soon. The potential is there, that's for sure.