Total Idiots Guide to buulding Ncore using Ghent cases

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zenpmd

  • Jr. Member
  • Posts: 160
If you do not want to undertake the fiddly efforts to build ncore amps with a substandard visual outcome in either home made cases or silicon ray cases (which have a lot of issues in my view – see below) then read on!

My motivation to get ncores was primarily because I wanted a class D amp that I could fix and broadly understand how it works so I didn’t have to rely on a manufacturer. Given that I propose to have these amps for decades I was alarmed that Cyrus just pulled the plug on servicing some old equipment last year so I decided to sell my Mono X. I also wanted class D over class A because they are small, light and don’t consume much power. It is my own personal belief that unless you need more than 200w per channel, it is impossible to improve on Ncore and when you consider how comparatively cheap they are, its an absolute no brainer.

The big benefits of Ghent Audio cases are:

1.   Its a nice looking case with ventilation built into the top and bottom already. This is the single biggest problem I had with siliconray cases, as creating ventilation was never going to be neat. In my testing the ghent amps are so much cooler. This is important for component longevity.

2.   They have a power switch built into the IEC. This means you do not need to worry about standby with the nampon cable, etc or sourcing and wiring your own switch. This is so helpful because with siliconray you can only fit a standard sized IEC and would need to do significant drilling.

3.   Ghent Audio now produce a power cable set, which is a series of pre-crimped internal power cables which ensure your IEC wiring is super neat and easy. It literally takes seconds to do and requires no soldering.

4.   Ghent Audio’s binding post spaces have the small notches on them required by a lot of binding posts and therefore ensures a secure fit with the binding posts provided. Do not expect these, however, to fit other binding posts without checking the specs as the dimensions will be different. Given that binding posts have zero effect on sound of your amp the included posts are fine.

5.   Ghent Audio is also in the process of producing Neutrik speakeron binding posts as an additional option, which are certainly my preference. I was personally promised the new back when its available free of charge. I am also talking to Ghent in relation to producing a speaker cable set like the iec set so you can avoid soldering here.

6.   Ghent Audio has pre built holes in the base of the case for connecting both the IEC and the XLR connections to the case (throughout this article I will not muddy the water by the swapping around of “earth” and “ground” and will simply refer to “connection to chassis” where appropriate. The IEC chassis connection (a small green wire comes pre crimped either end to connect to the IEC inlet and with a nut ring on the other end to effortlessly screw it down onto the chassis. The case works by providing longer screws for 1 of the feet ( I asked for 2 which you should too) and a small nut for the chassis connector (again, ask for 2), which in turn poke up through into the inside of the case, which you then screw down on with a small nut. I say ask for 2 because the same chassis connector is not included as standard for the XLR connection, but Ghent kindly included a pre made wire when asked. I think this will be included in future builds he produces. I will detail below how to wire the chassis.

For this build you need no tools other than a hex tool, a screwdriver, a solder and some wire strippers and cutters. After a bit of research in relation to high quality tools (which I didn’t own), C.K tools are a nice compromise between cost and quality. An automatic wire stripper like this is helpful in general. It guarantees clean stripping. http://www.ck-tools.com/products/ck_tools/electricians_tools/cable_and_wire_stripping_tools/automatic_wire_stripper/

No drilling or crimping is required with this build, which as explained above, is a massive benefit for cleanliness and ease and not buying uncessary equipment if you live in a tiny flat, etc.

I am presenting the information here as a step by step approach.

1.   The first step which can be a bit confusing is what people refer to when they say file/sand connections to ensure a proper connection with the wires that connect to the chassis. If you are using the ghent pre crimped wires (photos below), the connector itself is already designed to conduct, so you only need worry about the case. At the two connection points where you connect IEC and XLR to chassis you simply sand away the brushed black finish until you see the silver aluminium underneath. It makes sense to do this before anything is assembled to ensure the filings don’t fall on circuit boards etc.

2.   Next, before assembling the case, it makes sense to push the IEC connection into the rectangular hole on the back provided (with the switch at the top). It simply presses through and you have to be firm with it. Then, you can wire it up using the cables as shown in the photo below. Next, take the XLR connector and screw that into the case, then connect the binding posts which require no screwing. It is super important that no metal of the binding posts touch the case, so you have to put the 2 small plastic washes one on either side.

3.   A final step before assembling the case is to connect your chassis connectors. This is because it becomes fiddly otherwise. This means feet should be connected first, then you screw down using the nuts provided. The result here is that the back is sort of hanging on the chassis connectors on your work bench - connected using them and laying flat on your work surface (if that makes sense).

4.   Next connect the SMPS and NC400 to the case, using the screws provided. The connection from the amp to the SMPS is wrong on the ghent audio website (I have told Ghent this), because if the power input of the amp points toward the back of the case the power cable from the SMPS is not long enough to connect. It should instead be at 90 degrees to the back of the case, facing left, if the front of the case is nearest you. Then it’s a lovely tight and organised fit.

5.   At this point you have to screw in the speaker cables to the posts on the amp (not the case). These are wired in under the plate itself, not under the screw, so the movable square plate underneath applies upward pressure. A lot of people make the mistake here of the entry points of these wires. According to a direct forum post of Bruno the designer at Hypex, you must insert the speaker wires from the inside out, not outside in, nor in the same direction. This is very fiddly. It is then very very important that they be twisted tightly on their way to the binding posts of the case. A 1.5mm gauge wire is recommended. I stripped some Van dames down.

6.   Next, you screw together the case, which is super easy, only you must ensure you don’t put the front on as that comes last, once everything is finished otherwise its hard to connect the top (lid) of the case, so just screw the back and sides on. This is done by simply screwing the screws in the relevant place.

7.   Now you are ready to solder! You need a temperate controlled solder and set the temp to 400 degrees. There are various tutorials out there if you haven’t soldered before. The key things to remember – keep your solder clean when just idle to ensure you don’t get solder oxidising on the tip. To do this you use the damn sponge provided. When soldering, and particularly with the binding posts, you need to ensure all surfaces are hot otherwise the solder doesn’t flow well (as a side note, ensure you buy solder with flux included. Audiophile grade solder is a con so just buy standard stuff). You can get the heat up of the binding posts by simply holding a bare solder iron to them for a while. The next critical stage is to “coat”, in effect, the solder iron tip with solder, you do this by holding some solder directly to the tip to get some melted on. If you don’t do this it will not flow well from surface to surface. Then, at the relevant points, hold the soldering iron and push more solder toward it without touching the iron directly. It should then all flow over the top.

8.   In terms of wiring the XLR, its simple but because a lot of people are doing sublety different things on the net I was personally confused. First, examine the audio input cable. It appears to be one thick wire and one thin wire, however if you look at where it connects on the amp module and in the Hypex data sheet it is in fact four wires – there are three wires contained withing the thick cable. The thin cable on its own is the Nampon. I have no idea why but this must be connected to chassis. The blue and white wires must be connected to individual sockets on the XLR, while the metal shield surrounding these wires as part of the thick cable must be connected to the chassis like the Nampon. When mounted, the XLR socket has two connectors at the top, and one in the middle beneath it. Top left is pin 1, top right is pin 2, and the bottom pin is pin 3. The blue wire must be soldered into pin 2. The blue wire here is “positive” or “hot”. The white wire must be soldered into pin 3. This is “cold” or “negative”. For reasons I do not understand, pin 1 of the XLR must be connected to the chassis. It is customary for builders to therefore wire Nampon and sheild into pin 1 and pin 1 into chassis. However, you could also individually wire nampon, shield and pin 1 to case separately. In a future build once the speakeron connections have arrived I propose to wire the shield separately to the case because its fiddly otherwise wiring it so close to pin 1 and 2 and looks quite messy in most builds. Some people also choose to wire a little lug on the XLR in the bottom right of the socket to the case as well, but this is not necessary.

9.   At this point your amp is ready to be booted up. It is super super important not to touch anything when turned on, as the SMPS carries a lethal voltage. Even when turned off it is advised to wait at least 15 minutes for everything to discharge. Nevertheless, I decided to test the amp before closing it all up. A red light should come on.

10.   Once working, the front panel connects by screwing in the silver supports to you existing case, then resting the panel onto it and then using the mini allen key provided to use the tiny little screws to hold it in place.

11.   I did not want to have front led lights so decided not to wire these up.

And that is it! I will amend this to deal with any corrections or best practices once in receipt of comments and once I’ve gone back over the build, but I hope this helps those who are uncertain or confused by the process. From a personal perspective with my limited skills and knowledge I think using Ghent cases is pretty much mandatory!

Other points to note, it is totally pointless using any kind of IEC filter, power conditioning or any upgrade of that nature whatsoever. Bruno has confirmed it is not needed (as you would expect from a properly designed and implemented device).

Cheers!

clpetersen

  • Jr. Member
  • Posts: 30
Re: Total Idiots Guide to buulding Ncore using Ghent cases
« Reply #1 on: 18 May 2015, 08:24 pm »
Great posting, thx.  FYI, in your description of the XLR cable with nampon within the 4-wire bundle -- nampon ( meaning NOT amplifier ON) is meant to be grounded to enable the amp (a logic zero turns on the amp), so bringing it forward with the XLR bundle for a simple chassis grounding point is simple and smart. It also allows independent enabling the amp if you choose to do so.

zenpmd

  • Jr. Member
  • Posts: 160
Re: Total Idiots Guide to buulding Ncore using Ghent cases
« Reply #2 on: 18 May 2015, 08:32 pm »
Thanks clpetersen, thats helpful to know.

I should also thank all the members here who helped me with this build, you guys are awesome

zenpmd

  • Jr. Member
  • Posts: 160
Re: Total Idiots Guide to buulding Ncore using Ghent cases
« Reply #3 on: 18 May 2015, 08:38 pm »
Images as promised

IEC Wiring


Connected to chassis before assembly, also showing sanding (which should be done with cheap sandpaper to avoid buying a file!


Nice ghent chassis connectors