From the available data, I'd estimate that the SMPS600 supplying a single NC400 would support at least 160W continuous output without additional cooling, which is more than the nominal 133W suggested as a worse case scenario for playing music with an NC400.
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Review and Measurements of Hypex NC400 DIY Amp
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BobPM
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JimB, I noticed in the photos of your Ghent case NC400 builds (post#1102), that you upgraded the power cable and the speaker out internal wiring. I just received the Ghent case and it has the Ghent supplied power cable; however, the wire appears to be a little thin for a power connection. Can you share what you are using for the power and speaker connections and the source?
Also, what would you consider the ultimate internal cabling for the power connection and the speaker out from the NC400?
Also, what would you consider the ultimate internal cabling for the power connection and the speaker out from the NC400?
I consider the mains wiring from Ghent to be of adequate gauge and well twisted - certainly comparable to what Hypex offers. However, I wanted a margin of protection against power line emissions inside the chassis (there is no input filter on my model), so I chose to replace the stock leads with a star-quad configured, shielded run that I made. This is a bit of a fiddly task, at least as I did it, so you really have to want it to make it worth the effort. I can post some details, if desired. The braid shield is tied to ground at the point of entry, on the same lug as the mains chassis ground connection.
As for the speaker wires, I like the conductors of Belden 8471 (and 8473 and 8477) - I like that they are good quality copper, fine stranded and tinned. Ghent lists the 8473 (14 AWG) on their website, with the cases. The stuff is twisted pair in an outer jacket - nothing wrong with it for output connection as Ghent offers, but I wanted star-quad configuration, and that is unmanageable with this gauge. Ghent had 8471 (16 AWG), and were willing to sell me a few feet of it (like they do the heavier 8473). Doubled, it is equivalent to 13 AWG. I just stripped off the outer jacket, solder-tinned only the tips of the stripped region for the screw tags, to help get in all the strands, cleanly, and wound the wires into place as you see. It is a bit challenging to get those four wires into the screw tags as shown.
If you zoom-in, fully, on those two amp examples, you can see the details of both the mains and speaker wiring.
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BobPM
Active Member
Good advice. I'll stick with the Ghent power for now and consider changes latter. You mentioned "well twisted" Does everything get twisted?
Also, I have some parts express silver wire leftover from a speaker build, would that work for the speaker wire out connection? Any reason not to use silver in the amp?
Also, I have some parts express silver wire leftover from a speaker build, would that work for the speaker wire out connection? Any reason not to use silver in the amp?
Per the Hypex guidelines, twist the output wires together. Nothing wrong with silver if thick enough (at least 16 AWG, in my opinion) and connected well.
And preferably tightly, evenly and symmetrically.
Less important. The issue is the output leads picking up EMF from the amp itself.
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KJFaudio not only specs fans on their builds, but they only rate the NC500MP and 502MP at 100W continuous, while others go for the number Hypex just posts on their website, without looking into the spec sheet, which actually states 100W continuous. So, in most cases, I blame the manufacturers for using this 500W rating on some of the modules, when they (should) clearly know that the *respectable* method to rate the amp is continuous, and state the max output separately.
As such, I would expect the NC400 follows suit, even though its spec sheet doesn't even mention continuous power.
So, the 1/5 rating mentioned earlier about music peaks and requirements, probably applies to Hypex based designs on the internet. If you have a manufacturer posting a Hypex design of 500W into 4 Ohms, there's a high probability that it's only 100W continuous. However, we're still talking about excellent distortion and damping factor characteristics, perhaps only found in the better class AB designs, from what I'm reading here, and greater efficiency.
Nonetheless, it's not doesn't appear to be the pennies per Watt that most folks have thought they were paying for. All hypothesis of course, not an EE talking here.
As such, I would expect the NC400 follows suit, even though its spec sheet doesn't even mention continuous power.
So, the 1/5 rating mentioned earlier about music peaks and requirements, probably applies to Hypex based designs on the internet. If you have a manufacturer posting a Hypex design of 500W into 4 Ohms, there's a high probability that it's only 100W continuous. However, we're still talking about excellent distortion and damping factor characteristics, perhaps only found in the better class AB designs, from what I'm reading here, and greater efficiency.
Nonetheless, it
Hi, @Xyrium. From the NC400 datasheet, this suggested at least 133W, 'continuous', to me. What is your take on it?
https://www.audiosciencereview.com/...-hypex-nc400-diy-amp.5907/page-53#post-303498
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If they are only trying to meet the EN60065 standard at 1/8 power, I suppose it's even less, but admittedly, that caption in the middle of the sheet was not where I was looking. Shame on me I suppose for expecting their spec sheets to read in the same format (the NC500MP states the continuous power directly in the power output table), instead of using gray areas to spec their continuous output. So, I suppose my assertion stands, find those spec sheets before buying a Hypex-based build. 
NC500MP....pretty nice that they actually mention their 1/5 rule in the notes below the table....
NC500MP....pretty nice that they actually mention their 1/5 rule in the notes below the table....
As mentioned the continuous power capability will be dependant upon the thermal characteristics of the design. As shown in the video above the 252 will quite happily pass the FTC 5 minute full rated power test. Amir's test of the 502 showed it achieved 553 watts and 630 watts burst.
You also have to bear in mind the real world relevance of the figures. Music will never create a situation where the amps are required to deliver these full power ratings continuously.
So as a designer do you design for a situation that will never occur in real world usage? A situation that will only ever occur on a test bench? Requiring excessive heatsinking that will never get used?
No, it pointlessly increases cost.
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Whatever happened to the RMS watts for 20-20kh power rating? Wasn't it the legally mandated power rating for amplifiers sold in the US from the '70s onward. When and why was that changed?Take all the power figures here and dubble them and you get what the mono blocks will give you. But the mono blocks will be even more quiet as suggested when he did the measurement for one channel. The 400W is correct it's just confusing since usually 8Ohm power is the figure being talked about but the 400W is what these deliver in 4Ohm. The NC1200 for instance does not give you 1200W in 8 Ohm since that is the 2Ohm power figure
The NC400 is 200W 8Ohm, 400W 4Ohm, 580W 2Ohm like it says on their own website.
The continuous power rating for NC400 is 100W if I remember correctly.
But then people want to save money and buy multiple nc400 modules separately and the power supply that's intended to power just one of the modules. That's the issue with these power figures that it's missing a power supply.
In my opinion the continuous power is not as interesting. 100W continuous into your speakers is pretty damn loud.
As for turning the volume up more than with previous amps says not about the power of the amp at all. The amount of gain you get depends on the amps gain in combination with the pre-amps gain. The THX standard is 29dB gain but a lot of PA amps for instance have like 34dB gain and the nc400 have 26dB. So every notch on the volume nob would do less on something that has 26dB gain.
It's only relavant for advertising material it's not a mandatory test as such.
The FTC regulations from 1974 only address, as noted above, advertising, and prescribes a 5 minute test time.
e-CFR Title 16 Chapter I Part 432
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For some reason, I'm more comfortable with a manufacturer who draws a line in the sand. The more transparent the designer, the better. So, if someone quotes that they're selling a 500W/ch amplifier at 0.0005% THD+N and 115dB S/N; then you should state under what conditions that amp reached those results (continuous or max output).
Please don't get me wrong, I still see the value in these modules, just not consistency amongst manufacturer reporting specs. For instance, NAD uses a UcD102 module in their C368 integrated that I have. The spec sheet doesn't mention whether the 100W on this module is continuous or max, but NAD is stating 80W/ch "continuous". Given how small that single board is, and the single PS used in the design, I have a hard time believing that the old ucD102 can even do 80W continuous when their supercharged NC400 can only do 133, est.
https://www.hypex.nl/documenten/download/838
Please don't get me wrong, I still see the value in these modules, just not consistency amongst manufacturer reporting specs. For instance, NAD uses a UcD102 module in their C368 integrated that I have. The spec sheet doesn't mention whether the 100W on this module is continuous or max, but NAD is stating 80W/ch "continuous". Given how small that single board is, and the single PS used in the design, I have a hard time believing that the old ucD102 can even do 80W continuous when their supercharged NC400 can only do 133, est.
https://www.hypex.nl/documenten/download/838
No such thing as RMS watts -- average power is the product of RMS voltage and RMS current.
The continuous power rating and 1/3 power preconditioning requirement (now 1/8 power) was dropped some time back ("watered down" IMO, for manufacturers, and requirements for full testing of all channels was dropped/never addressed). I have the FTC docs but not handy (not even sure here they are now). They've been quoted before and are online, I think.
I posted the link to the The FTC regulations from 1974 3 messages back
Well, clearly you need to post it more often for senile old farts!
I've been working a lot lately so only skimming. Thanks, I need to grab it!Similar threads
