Multi Channel Ncore Amplifiers

MA-01 multi channel hypex n-core amplifier rear 13


We don’t sell any other brands of amplifiers, just our own designs based upon the Hypex N-core NC***MP series of amplifier modules. The MA-01 is a fully customisable multi-channel amplifier. Designed for a world of changing needs, this amplifier can be reconfigured back at base so that as your audio setup changes so too can your amplifier. Need a 500/250/125 Watt stereo amplifier for your DIY active speaker build, no problem. Need 6 x 250 Watt channels for your home cinema set up, no problem. A standard stereo set-up, no problem. Return to base to reconfigure your stereo amp for active speakers, no problem. This Hypex Ncore amplifier was designed in a modular way to allow us to build a custom amplifier for each customer’s needs without every amplifier being a fully custom ground up build. The MA-01 uses the Hypex N-core modules that in Hi-End hi-fi have become synonymous with very high performance.

Selecting the amplifier product to the right will give you a completely flexible amplifier configurator. Our fully configurable multi-channel N-core MA-01 amplifiers are built around our control PCB, each PCB has 4 ‘slots’ you can fill on the control PCB and each of the modules use up 1 slot allowing your choice of Hypex NC***MP modules offering 4 different power outputs across 7 different modules. You can use the configurator to  configure your Hypex N-core amplifier for your exact needs. ​This can be a stereo or mono amp as well as a peerless multi channel AV power amplifier. They also make an ideal base for active speakers like Linkwitz 521‘s, Linkwitz Orion, or any of your DIY active speaker projects.

We also make Stereo and Mono block amplifiers aimed at the 2 channel audiophile customer should you prefer that, see this page.

I believe in getting the best functionality, great quality and maximum flexibility possible in an amplifier. I’m not a great fan of spending thousands to do so. Looking at today’s high end audio industry I found myself very disappointed with what is available. There is some great engineering out there but it is often overlooked at the expense of more easily marketed concerns. The latest flagship amplifiers from well known amp manufacturers often contain the same circuit they have used for decades but now command astronomical prices. The difference? Often just a posh, CNCed from billet, box and some marketing fluff. Yes we used CNC but did so in an efficient way using only the material needed to make a functional amplifier box.

MA-01 Case lid during machining
MA-01 Case lid during machining
MA-01 Case lid before Anodising
MA-01 Case lid before Anodising

I wanted to make something that was absolutely cutting edge in its performance, up there with the best amps money could buy, but I also wanted to ensure value for money, all of the products at KJf audio are based on them same goals. The amp needed to be as flexible as possible while providing a high level of good electrical engineering. These 4 design tenets set the design goals. And this is how we achieved them.  

Cutting edge performance

This was a bit was easy, I’ve followed the development of Hypex amplifier modules for a long time. I’ve used their various DIY amp modules and plate amps in projects of my own, they are extraordinary amplifiers and in the N-core versions have reached a unsurpassed technical refinement. The N-core modules are found in a wide range of high-end amplifiers where their advantages are available at a high price. There are loads reviews of very high end amplifiers all over the internet and in magazines that contain these modules, active speakers and amplifiers from the likes of Kii, Bel Canto, Mola Mola, Jeff Rowland, Nad, Meridian, Theta Digital Drednought, Classe, Mark Levinson, Nord, amongst others. The N-core circuit is designed by Bruno Putzeys, an electronic engineer of almost legendary status. Bruno’s research into non-linear control theory has been a 20 years in the making. The technical results speak for themselves, low distortion, noise and output impedance are as close to being a straight wire with gain as is currently possible. The amps just get out of the way of the signal so you can concentrate on the rest of the audio chain.

Hypex NC502MP module

Value for money

This is more difficult than performance, I didn’t want this amp to be beyond the budget of the audio and cinema enthusiast but wanted to maintain the commitment to the 4 tenets I mentioned above. What is it that makes other amplifiers so expensive? The easiest target is the posh box. Most of the amplifiers containing these Hypex NC*MP modules are very high end and are machined into beautiful objects from billet aluminium. They do undoubtedly look every bit the statement piece they are meant to be. Placed with a sense of pride they draw admiring glances from your jealous visitors. Nothing wrong with that of course, we all like beautiful things, if you are prepared to spend more money to get that, then that is the way to go. I decided to use off the shelf cases from a supplier I’ve and many self-builders have used in the past, with a minimum of extra CNC work to suit my needs. It took me many months going back and forth with production prototypes to come up with a design that looked good enough to grace most audio racks but also to allow the flexibility I wanted to provide a build base while keeping that build time to a minimum.

MA-01 rear before anodising and printing
MA-01 rear before anodising and printing
MA-01 rear after anodising and printing
MA-01 rear after anodising and printing

Thar work was essential, an amp can either be an identical production line build, which keeps costs low, or it they be custom and each build requires the case customising. That leads to a much more expensive build but also to a bit of a DIY feel to the end result. I designed a case that allows a custom amplifier build each time with no extra customising needed. Distribution also costs. Employing a distributors network for each territory, then adding a layer dealers ads up. Say an amp that cost £100 to build, even at only 30% mark-up the price multiply. £100 becomes £130 for the manufacturer, £169 for the distributor and £220 for the dealer. That is an extremely simple chain, with very low mark up. There would be transport between territories, currency fluctuation, marketing and branding as well, maybe even further layers. A direct sales method where I sell you the amplifier direct is the only real way around those costs. 

The specifications

Built around a single circuit board containing all of the connectors and electronics the microprocessor-controlled circuit provides all the back panel Inputs and house keeping duties required by the amplifier modules and provides a simple user interface. Each amplifier module provides feedback about it’s status to the housekeeping board, electrical status, temperature, DC detection, and clipping are all monitored, recorded and presented to the user. Error states are displayed on the RGB LED ring around the single push button on the front of the case and modules are shut down under extreme conditions. 

MA-01 Ncore MP control board
MA-01 Ncore MP control board
LED ring to show amp status

The controller also controls the on board dual near silent 120mm PWM fans. 6 x 500 Watt amps or 8 x 250 Watt amps can pull a lot of current! Class-D amps are magnitudes more efficient than Class-A some heat is still produced which needs to be controlled. A lot of manufactures ignore this because of the efficiencies of class D amplifiers and for the most part that is OK, I wanted to ensure cool running in as many environments as possible. Due to keeping the costs affordable, huge heat sinks were out, we decided on 2 large silent pulse width-controlled fans. The internal temperature of the amplifiers is fed back to the microprocessor which in turn can regulate thermal limits. If the amplifiers start operating above their nominal range the microprocessor starts turning the fan slowly enough that they are inaudible, pushing the volume and potentially the temperature even higher, the fans speed up to compensate, even at full RPM they are <20dbA. They are electrically isolated from the rest of the system so as not to interfere with delicate audio signals in the rest of the amp.

MA-01 multi channel amplifier left hand fan outlet
Silver MA-01 multi channel hypex n-core amplifier top panel fan
close up showing the top of the ma-01 with the fan outlet in the foreground
Black MA-01 multi channel hypex n-core amplifier top panel fans

The amplifier modules are fully differential (balanced) and so it is possible to connect both fully balanced sources or single ended sources. I looked at the engineering of the competition and almost without exception they provide both an XLR for balanced connections and a phono for single ended connections, however, you can only use one at a time so there is a switch provided to switch to one or the other. I didn’t want a switch in the signal path on this amp so I decided to use the much more modern combo connector from Neutrik which can provide either a balanced or single ended connection via gold plated pins directly to the gold traces on the PCB. Balanced connection is achieved via the tried and tested (AES 48 compliant) XLR cables and single ended sources via a phono to XLR cable, which will provide a shielded cable run or any unbalanced cable with a ¼ inch TR (tip/ring) connector one end, which will also insert directly into the combo connector. OK, your posh audiophile cable with solid silver phono plugs either end will be redundant, but you’ll be using high quality well designed industry standard connectors instead. 

XLR connectors providing a differential (balanced) connection
1/4 inch Jack (TR) connectors providing single ended connection

Connecting your speakers using a high quality, solid and versatile connector that takes any wire you would like to use is important, especially when you can potentially supply your speakers 500W of power. The audiophile CMC branded gold plated connectors tick all of the audiophile connector boxes but at a sensible price point. They take a standard 4mm banana/spring/z-plug if you’ve got cables terminated like the speaker cable kits or terminated speaker cables we sell. The outer barrel is also threaded and opens up so that you can clamp down on large spade connectors or 10mm² cable. The robust thread will hold even the heaviest cables in place. Alternatively for pro users or just those that prefer them another possibility is the optional Neutrik Speakon back panel available at no extra cost.

medium closup of the MA-01 rear panel showing the binding posts
MA-01 multi channel hypex n-core amplifier with CMC binding posts
MA-01 multi channel hypex n-core amplifier rear 12
MA-01 multi channel hypex n-core amplifier with Neutrik Speakons

Installation friendly

The front panel can be specified as an installation friendly 19 inch rack mount panel. If you run a mobile sound system or if you have your amps hidden away in an equipment room this is the option for you.

We also include a 12 V trigger as standard so the amp can be triggered in and out of standby using a 12 V signal in you AV installation

It is important, in the global world we live, to ensure the amplifier can be used anywhere the prospective customer might live in the future. In the past with linear amplifiers it has been necessary to change transformers for the local power. You can plug 230V or 110V power into this amplifier and it will auto switch so you can move around the world and take your amp with you. 

12V trigger cable inserted into MA-01
12V trigger cable inserted into MA-01
IEC connector inserted into M-01
IEC connector inserted into M-01
  • up to 8 channel – choose from NC122MP, NC250MP, NC252MP, NC500MP, NC502MP and NC100HF Hypex Ncore modules
  • Installation freindly
  • Fully balanced and single ended operation
  • No switches in the signal path
  • AES-48  compliant
  • 12V trigger
  • 47K Ohms Input Impedance, low output impedance
  • S/N Ratio 118dB – this is based on measurement of individual modules
  • THD 0.0015
  • 26dB Voltage Gain (except the NC100HF module which is 20dB
  • Overall case size – Width 450 mm, Height 90 mm, Depth 350 mm
  • Single button interface function control and warning
  • Microprocessor controlled
  • Muted start-up process for pop free operation
  • DC detection and protection from DC produced during catastrophic amp failure
  • DC connected inputs (make sure you have no DC on the inputs)
  • Clip indication
  • Active temperature control and indication
  • Industry standard Multi function Neutrik connectors which can take and XLR or 1/4 Jack connector for balanced or single ended connection
  • Custom made Audiophile quality CMC speaker connectors or Neutrik speakon connectors
  • Gold PCB traces
  • Gold plated internal connectors
  • No silly marketing foo to confuse you
  • 230V and 110V operation via the IEC connector as standard
  • A white area on the rear panel to write channel notes

This video is a short but handy resource showing the button/LED interface. It was made to show the Kickstarter backers what to expect on delivery.

This video is the original Kickstarter video which I produced to raise the money to build the original production run. I used to work in TV so producing a video wasn’t a problem – presenting was though!!

If I get a multi-channel version do I need to have a source and speakers into all the channels?

No not at all, you can use an 8 channel amp as a 2 channel amp if you want. There is no need to have either a signal or a speaker plugged into any of the channels.

Some manufacturers provide the ability to change the op-amps in the input stage of the amplifiers to change or ‘improve’ the sound, do you?

These latest N-Core modules have got a buffer already built in, Bruno Putzney (N-Core designer) is one of the most talented audio designers on the planet so I’m pretty sure he’s got this well sorted in these modules. Most of these off-board buffers use op-amps which must exist in a circuit that is designed and optimised for that op-amp. Op-amp ‘rolling’ should be discouraged, as putting a supposedly high performing op-amp into a circuit not designed for it can cause oscillations in the circuit that will cause non-linearity further down the line. I don’t provide this functionality, I want to make amplifiers that are unconditionally stable into all loads.

I was asked why a potential backer shouldn’t just buy a Nord or Apollon amplifier or one of the other similar looking NC boxes out there.

There are 2 big differences. Firstly it is very flexible, it allows a user to return to base to have modules added or swapped without having to completely rebuild the whole amplifier. The ability to cater for every configuration is built into both the case and the control board. This ability for the control board and the case to cater for this means that each build is not only a custom build but at the same time it is able to be built with production line ease. The problem with most ‘custom’ builds is that they end up looking a little DIY in their execution. I wanted to get away from that feeling while still being able to offer full customisation.

The second major point of difference is the control board, it allows the amplifier modules to communicate to the user things like DC detection, temperature, clip, error shutdown etc. It controls start-up sequence to stop fuses blowing on power up and 12V triggers can be implemented as standard. It also provides for intelligent cooling which neither of the others do. Class D amps are obviously very efficient but pulling 6 x 500 Watts from the mains still potentially generates a lot of heat if those amps are being pushed to those limits. In this design a pair of large and essentially silent fans can be pressed into service should things get a little warm, under most domestic listening circumstances or course they don’t. Even the very high end Ncore based offerings don’t offer well thought out cooling.

As you noticed Apollon and Nord also use the same off the shelf cases in an effort to keep the costs down so a similar look is inevitable as is the question you pose. I’m pretty happy that my version is much more flexible and offers greater functionality to the user at similar prices though.

The amplifier is balanced, how should I connect my source?

The NC***MP (ncore) modules have a fully differential input and so can accept a balanced input. KJF audio have provided a combo connector to which you can connect your source. The combo connector is the new industry standard connector from Neutrik that can accept either an XLR or 1/4 inch Jack connector.

If the source equipment you are connecting to is balanced you have 2 possibilities for connection. You can either use an XLR with pins 1,2 and 3 on one end of the cable connected to pin 1,2 and 3 the other end. Alternatively you can use a 1/4 inch TRS in that case pin1 goes to to the ring, this is the shield, pin 2 goes to the tip, this is hot and finally you connect pin 3 to the ring, this is cold. You can purchase a standard XLR cable in our web shop just here.

If your source equipment is unbalanced (single ended) and uses a phono connector for output then you have 2 options. If you prefer to continue to use your existing phono to phono cables you will need an adaptor. We have scoured the suppliers to find the phono to XLR adaptor that we think is the best out there, we sell the Xcaliber connector here on our webshop and that is our recommendation of you prefer to use your existing cables. The second option, and this is our preference from a technical point of view is to use a dedicated phono to XLR cable. This should be wired so that pins 2 and 3 are connected to the shell of the phono connector and pin 2 should be connected to the phono pin of the phono shell as per the diagram below.

XGA34 XLR to phono diagram
XGA34 XLR to phono diagram

This section will contain a downloadable instruction manual in time