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Review and Measurements of Hypex NC400 DIY Amp

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I do care about making stuff better, but I am an engineer - I approach it based on facts, and what matters.

I also tend to believe in a kind of modified version of Godwin's law - if someone has to resort to childish personal attacks, it is a sign that they have run out of rational arguments, and there is no point in continuing the discussion. Have a good day!
Hey Julf,

Hate to disillusion you but I am an engineer. Just because someone doesn't agree with you doesn't mean they don't like facts. Might want to check in with reality someday. Fact is that trying to make anything better than you would bother is not wrong and is the option of the person doing it. Build what you want the way you want and leave the rest of us alone. Just get over yourself.
 

Julf

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Hey Julf,

Hate to disillusion you but I am an engineer. Just because someone doesn't agree with you doesn't mean they don't like facts. Might want to check in with reality someday. Fact is that trying to make anything better than you would bother is not wrong and is the option of the person doing it. Build what you want the way you want and leave the rest of us alone. Just get over yourself.
Have a good day!
 

Alan0514

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Greetings,
I'm new to this forum but have been using a pair of NC400/SMPS600-V3 mono-amp for a few years. One of the 2 did not turn on recently after a year of being unused. The fuse is not open. The caps and coils appear to be intact. The row of LEDs located in the middle of the NC400 module blinks once every 2 seconds. I've written to Hypex but haven't got any reply yet. I hope someone here can point me to the resource to troubleshoot the issue, even replacing the faulty amp or PS module. I apology if this is not the place for these type of query.

Thanks in advance for your time and help.
 
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Hi all,

I bought an Y splitter cable xlr to feed my nc400 amplifier and my active subwoofer, the source is Dac SMSL M500 used with variable volume.

Do you know if there are problems by doing that? I imagine loss of details because I don't use sufficient volume level on M500 (I'm usually about 20 off 40 max) but there would others "technical issues" or sound quality loss by using the xlr splitter?
 

Sal1950

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Do you know if there are problems by doing that?
I imagine we would need the output impedance of the DAC and input of the two amps to determine that.
 

Sal1950

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Not at all :(

For nc400 it was built by another person with hypex components.

Elac sub 3070 no datas on xlr impedance

Smsl dac M500 I've not found
 

MBI

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What I have is a Hypex SMPS that is rated to power three NC400 modules. That gives me about 50% leeway and I consider that more than enough. Supply should not have to work as hard as a smaller one and should run cooler as it is designed for higher currents as well. Both pluses as far as I am concerned.
Could you please confirm that each of your NC400 have their own SMPS1200A400 and, if so, if the overall temperature of the case gets warm when you touch it or not at all (after long and loud listening sessions) please?

It has been explained earlier in this same thread (several times), that the voltage was slightly different between SMPS1200A400 (2x64V) and SMPS600N400 (2x65V). The theoretical consequence of that would be that the NC400 would have to "compensate" (or whatever it is) the lacking volt when powered with the SMPS1200A400, which should make it run warmer. So the bigger power supply may possibly last longer (heats less), at the expense of running the amplification unit warmer... which may or may not impair its performance (or even its longevity). If someone had the skill to evaluate the potential impacts, I'd be grateful!
 

MBI

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As nobody's responding here, I asked Hypex DIY directly: same heat will be dissipated from SMPS1200, making very little difference with SMPS600. So it would work, but not any better.
 
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Hi...I have been reading up on this and am VERY build-amp "curious" ....Is there a set of plans and/or instructions to build this exact amp out there. (Is this the Hypex Mono Kit?). I am capable, but would need specific, detailed guidance to assemble this project.....
How do two of these mono blocs differ/compare to the Hypex UDC400 Stereo Kit from a sound standpoint?
 
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anphex

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I have a small question. Recently I became an owner of two monoblocks and built them myself. I swapped the speaker wires shipped with the module with thick isolated single copper wires because the aluminium filament cable felt weird and also was too big to fit it comfortably into the sockets.

From my POV they work perfectly fine. When I get close to the tweeter there is a slight, smooth noise audible but I guess this is normal. Now my question: is there a way apart from measuring to know that I don't have any bloopers in my built that could ruin these good values? I did everything carefully and checked twice but I am still a little unsure.
When I plug in the RCA-XLR Cables from my Denon AVR I start to get some very slight hisses, also at about the same volume as the base noise, but I guess this is just due to the unbalanced input.
 
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Julf

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I have a small question. Recently I became an owner of two monoblocks and built them myself. I swapped the speaker wires shipped with the module with thick isolated single copper wires because the aluminium filament cable felt weird and also was too big to fit it comfortably into the sockets.
Did you twist them symmetrically and tightly?
 

anphex

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Did you twist them symmetrically and tightly?
Yup! About 10 twists per cable pair per amp. I also took care to press the cable core against the speaker twist ports and not to clamp it between just the screws. When I don't have any pre amp plugged in the sound of the base noise is identical. I also checked the grounding multiple times.
 

Julf

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Yup! About 10 twists per cable pair per amp. I also took care to press the cable core against the speaker twist ports and not to clamp it between just the screws. When I don't have any pre amp plugged in the sound of the base noise is identical. I also checked the grounding multiple times.
Then I assume it is just the normal input noise.
 

anphex

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Okay, the cable twisting stuck in my mind and when I came home today I minimized the free floating cables between the amp and speakers and the preamp and amp. The noise is now almost completely gone. Never expected twisting the cables would be such an easy remedy.
 
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