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Review and Measurements of Hypex NC400 DIY Amp

DonH56

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Wonder how much the external heat sinks are really needed...
 

Julf

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The internal layout of the Audiophonics implementation looks nice to me, with separate power supplies, and plenty of distance between the two pairs of amps and power supplies. Does anybody else have any comments on the apparent quality of that layout?
The twisting of the speaker output wires looks rather amateurish.

I hope that they also make it available with a North American power supply.
The SMPS600 is dual-voltage (and auto-switching).
 

JimB

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The internal layout of the Audiophonics implementation looks nice to me, with separate power supplies, and plenty of distance between the two pairs of amps and power supplies. Does anybody else have any comments on the apparent quality of that layout?

I hope that they also make it available with a North American power supply.
Indeed. You might ask why it is rated for 'only' 230VAC. The SMPS600N400 is auto mains range switching. Perhaps there is an LED in the front panel switch that will not light with 120 VAC?
 

JimB

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Wonder how much the external heat sinks are really needed...
Me too. If I wanted to improve thermal margin (which I did), it would be for the SMPS, which has no meaningful path to those heatsinks. Anyway, they certainly don't hurt, and they make it look a more serious amp*.

* In traditional terms
 
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VintageFlanker

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Big alert ! :eek:

@Audiophonics is releasing an assembled NC400 Amp. It'll be called PA-S400NC.

View attachment 36406
View attachment 36407
View attachment 36408
View attachment 36409

View attachment 36411







Double SMPS600 PSU! So it would deliver as much as monoblocs kits.

1490€ inc VAT, so quite more expensive than their PA-S500NC... but still on par with two NC400 DIY kits from Hypex (699€ each)... and at least, it is assembled already. Is that the first NC400 DIY implementation to date?
In stock now!
 

87mpi

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Is it possible to connect and power a single nc400 module with smps1200 400/700? could there be improvements using smps 1200 over the 600 (apart better dissipation for 1200) in mono block (not bridged)? Many thanks. Antonio
 

JimB

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Is it possible to connect and power a single nc400 module with smps1200 400/700? could there be improvements using smps 1200 over the 600 (apart better dissipation for 1200) in mono block (not bridged)? Many thanks. Antonio
Possible? Sure. No performance benefit (other than heat sinking to the case). I use an SMPS1200A400 for two NC400s, using the Hypex connector kit, as intended.
 
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The twisting of the speaker output wires looks rather amateurish.
Certainly seems like someone fell asleep during assembly! The Hypex datasheets do actually elaborate on numerous occasions the importance of tightly twisting the cables... so someone obviously forgot to deliver that memo or didn't care enough to do so, and that's always a cause of concern because now I'm just going to keep thinking "so what else did they eff up."
It is very important to use twisted pairs for the output cabling, at the very least anywhere near the PSU cabling. The distortion of the NC400 is so low that it is easily exceeded by magnetic coupling between the supply wiring and the audio wiring.
Tightly twist all loudspeaker cabling inside the chassis.
 
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Wonder how much the external heat sinks are really needed...
Probably not at all, seems like a waste to me.

My old power amplifier contained two ICEpower 125ASX2 modules (500W into 4Ω per channel/module) and they were seated in the middle of an almost-sealed enclosure without any additional cooling and they survived just fine. And off the top of my head the ICEpower modules are less efficient than the Hypex NC400's (though not by much); and also the SMPS for the ICEpower modules are built directly onto the amplifier modules themselves which ought to make things toastier still. And I left them on 24/7.

The thing is though the vast majority of Class-D amplifiers are so ridiculously powerful that you'll pretty much never ever get close to running them continuously anywhere near their technical and thermal design limits, and even if you do it ought to be rare.

It's nice to always be miles away from distortion though :D
 

JimB

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Certainly seems like someone fell asleep during assembly! The Hypex datasheets do actually elaborate on numerous occasions the importance of tightly twisting the cables... so someone obviously forgot to deliver that memo or didn't care enough to do so, and that's always a cause of concern because now I'm just going to keep thinking "so what else did they eff up."
While it could be tighter (mine is), and extend a few mm closer on each end (mine does), it is not bad, and, at least it is not routed along the PSU wiring (though Hypex has the connectors adjacent on the PCB). IF they have good assembled unit performance data, that would settle the concern.
 

Julf

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While it could be tighter (mine is), and extend a few mm closer on each end (mine does), it is not bad, and, at least it is not routed along the PSU wiring (though Hypex has the connectors adjacent on the PCB). IF they have good assembled unit performance data, that would settle the concern.
Bruno was pretty specific about stuff like which way the leads should come out of the connectors to minimize the area that can pick up EMF.
 

Matias

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Interesting that 2 monos is cheaper (1400 euros) than 1 stereo (1500 euros).
 

Julf

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The symmetry of that layout looks really nice, but I put a lot of care into ensuring a wide separation between all internal wiring. What you can't see from any of the pictures I took is how far apart wires are, especially when paralleled. I used a chassis with a pre-drilled rear plate, so inputs and outputs had to be paired together. This meant that external wiring was optimized at the expense of short and channel symmetrical internal signal paths, but I think this is an acceptable compromise since the internal wiring only needs to be optimized once. The external wiring is the one that's going to vary.
 

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rajapruk

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The symmetry of that layout looks really nice, but I put a lot of care into ensuring a wide separation between all internal wiring. What you can't see from any of the pictures I took is how far apart wires are, especially when paralleled. I used a chassis with a pre-drilled rear plate, so inputs and outputs had to be paired together. This meant that external wiring was optimized at the expense of short and channel symmetrical internal signal paths, but I think this is an acceptable compromise since the internal wiring only needs to be optimized once. The external wiring is the one that's going to vary.
Nice build.
One optimization you can do is to wire both the internal speakerwires to the inside of the screw-connectors at the nc400 end, to reduce the pickup loop the cables are forming. To get minimal distance between the cables.
 
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