Hypex NC400 mono kit build review

[miiaow]

Please note this is not an audio review, although I do think they sound great

I just finished building 2x Hypex NC400 monos and wanted to review the kit and the build process. I do not have any education in electronics or electricity, but it has been a hobby for a while.

Link to the product: https://www.diyclassd.com/product/nc400-mono-kit-complete-kit/24

The kit came in a small box with all the necessary parts and tools.

What you get:

• 1x NC400 amp
• 1x PSU
• 1x metal case
• a short two page assembly instruction
• plus all required internal cables and screws as well as connectors for speakers, power, input etc.

I was pleased to see that all the components included were of apparently high quality. The only component that looked a little bit off was the XLR socket which appeared to have been soldered a bit hastily in my opinion (this is an easy fix if you have a soldering iron though, should you feel the need to improve it)

In addition to the included material, I got some more material for the build:

• zip tie holders
• more zip ties
• braided cable sleeving (I used Ø 6mm for the internal mains cable)

The first kit took me about 4 hours to build. The second one took a little less, having learned some lessons from the first build:

• Remember all washers when screwing the case together
• Read every step in the instructions carefully
• Fasten the internal speaker cables to the back of the binding posts before screwing the backplate onto the chassis
• Fasten speaker wire repeatedly to compensate for the wire moving slightly and creating more space
• Shorten the exposed part of the amp end of the speaker wire (so they wont extend too much from the terminal)
• Don’t skip glueing the power cable socket to the chassis

The only major difficulty I had was fastening the thick internal speaker wire to the amp’s terminals. The pcb screw terminals are placed really close together and only one of them is on the edge of the pcb. Also, the space in the terminal is really tight, even when it is screwed out to the max (don’t screw it all the way out though, this will make the small square squeezing the wire from underneath drop off and it can be a little difficult getting it on again). The picture in the instructions shows the speaker wires entering the terminals from the same side, which is hard to accomplish. Since I didn’t know if letting the wire enter the terminal from the other side would have an impact on audio quality (this would have the speaker cable directly above pcb components), I tried to do it as detailed in the instructions

Other than this the build was very straight forward and I was very pleased with the result. As an added bonus with a DIY kit you get a little extra excitement when you power them up for the first time since you could have misconnected something and blow a fuse

Tested with setup: Topping D50s dac, jds labs atom pre-amp (rca to xlr cables) kef ls50 speakers, 10 meter 4mm² speaker wire

 

[Tom C]

Very nice! I’m planning a pair of these myself. Thank you for the build tips.

 

[Daverz]

Please note this is not an audio review, although I do think they sound great

I just finished building 2x Hypex NC400 monos and wanted to review the kit and the build process.

What tools were required for the build? Any soldering required?

 

[g29]

What tools were required for the build? Any soldering required?

This build video shows all of the tools you need to build the kit (starting at timecode 0:27). Soldering is required for the XLR connectors.

 

[Tks]

When you want to build your own power amps but you realize you only have powered speakers..

 

[McFly]

What tools were required for the build? Any soldering required?

My kit last year required no soldering. I believe they changed the kits about a year after they were released to solder-less.

 

[g29]

My kit last year required no soldering. I believe they changed the kits about a year after they were released to solder-less.

With the new kit, did you have to do any stripping/crimping as depicted in the build video or has everything been pre-cut and pre-terminated ?

TIA

 

[McFly]

I can’t recall exactly but I don’t think any crimping or stripping was required. It was very, very easy. Instructions were a little... light, but you’ll get there in the end. I took about 1.5hr per amp.

 

[Koeitje]

How are they on your LS50's and what were you using before?

 

[miiaow]

What tools were required for the build? Any soldering required?

Tools not included in the kit: slotted (3.0mm) and phillips (#2) screwdrivers
No soldering required (XLR connectors are pre-soldered, but if you feel you need to re-solder them that’s up to you)

 

[miiaow]

How are they on your LS50's and what were you using before?

I’m really happy with the setup, especially that I feel I have enough to go on (speakers play loud enough for me way before the volume half way point on my atom pre-amp (extra gain button disengaged)). The speakers are new so didn’t use anything before this so I have no reference.

 

[miiaow]

Another postive thing to note about this kit is that the case has been carefully constructed to make sure all parts are connected to the grounding bolt (just make sure you use all the washers).

To me, this is a sign of good attention to detail and safety.

 

[g29]

Another postive thing to note about this kit is that the case has been carefully constructed to make sure all parts are connected to the grounding bolt (just make sure you use all the washers).

To me, this is a sign of good attention to detail and safety.

Are the XLR shield grounds grounded to the XLR case mounting screws (see green jumper on XLR's shield ground) ?

 

[miiaow]

Are the XLR shield grounds grounded to the XLR case mounting screws (see green jumper on XLR's shield ground) ?

Yes they are, just did a continuity test and pin 1 and shield are both connected to chassis ground.

 

[archerious]

Are the XLR shield grounds grounded to the XLR case mounting screws (see green jumper on XLR's shield ground) ?

That looks a lot better than some of the used VTV amps I've been looking at.

 

[Mars2k]

Are the XLR shield grounds grounded to the XLR case mounting screws (see green jumper on XLR's shield ground) ?

So this is a stereo kit right? Where did you source that please? I asked Mr. Google he kept pointing me to DIYClassD

 

[phoenixdogfan]

So this is a stereo kit right? Where did you source that please? I asked Mr. Google he kept pointing me to DIYClassD

Hypex only sells dual monoblock kits. You can assemble a stereo amp by buying the individual components from Hypex (2 SMPS600 power supplies, and 2 NCore 400s, a wiring kit), and then buying a Stereo chassis from Ghent Audio in Hong Kong.

Or you could just buy the monoblock kits from Hypex which have everything you need.

Same guts either way. Just depends on whether you want two monoblocks, or a stereo amp.

 

[Mars2k]

Exactly what I wondered...where did the case come from..Thank you

 

[birkbott]

Just finished building my pair from Madisound and they sound really nice. Super super clean. Lots of power. No stress at high SPL levels although my speakers are easy to drive.

They are bigger than I thought they were based on pictures. The cases are super sturdy and thick. A little fiddly to get them together but overall the build was very easy (no solder!) and I’m very impressed with the quality.

 

[TheWalkman]

Since they’ve apparently changed from soldered connections to quick connect style lugs, would it be ill-advised to put a dab of di-electric grease on the spades to avoid oxidation and better longterm electrical connectivity?