Review and Measurements of Hypex NC400 DIY Amp

[amirm]

It was rated 125X5 and 185X5 weight 58 pounds. Now this was an all channels rating which was their standard rating they used for all amps.

Another lightweight. My Proceed Amp-5 is rated the same 125 watts a 8 ohm but weighs 115 pounds!

 

[garbulky]

Another lightweight. My Proceed Amp-5 is rated the same 125 watts a 8 ohm but weighs 115 pounds!

Nice!

 

[amirm]

To fess up as far as all the amps I have , this is the other one:

121 pounds gets you stereo 400 watts/channel into 8 ohms.

 

[6speed]

https://www.stereophile.com/content...erence-monoblock-power-amplifier-measurements

• Figure 5 does not look as impressive as I was expecting it to be.
• Figure 13 is a good test if your AP can do it.

@amirm Any chance we can talk you into putting a ML on the bench? If you were nearby, I would offer to help with the heavy lifting.

 

[Deleted member 65]

I am measuring continuous power for a minute or so.

[QUOTE="amirm, post: 132684, member: 2"What I measure is constant although I don't let it sit and do that for minutes or hours.
[/QUOTE]

Sorry for lingering on on this, seems as we're long way from agreeing.

I get we shouldn't abuse equipment loaned from members, performing cont. power testing, as per FTC may be not a good idea.

However I think there's a slight carelessness on usage of words in the review which may be confusing at least for the average consumer, see quotes above. Published figures concerning power capacity in this otherwise excellent review are misleading and contradictory at least for the average consumer.

Until we have some agreement in the community on how poweramps should be tested I suggest we use the since long agreed upon terms Peak Power & Continuous Power. Those are also terms used by Hypex in their documentation.

Otherwise I'm not hard to pursuade using Music Watts ... ;-)

 

[restorer-john]

This has been done many times over the years but AFAIK the only "standard" is the IHF burst test

The IHF/EIA or EIAJ tonebursts were for short term 'clipping headroom' type testing. Most the magazine reviewers and manufacturers standarised on those tests many years ago, in addition to continuous. Alan is going to take some numbers on his March amp modules using those standards.

...I suggest we use the since long agreed upon terms Peak Power...

Peak power is 'long agreed' as exactly what? It's never been taken seriously in any publication I've ever read. Taking the peak voltage of the waveform, squaring it and dividing it by the load resistance to obtain a false number that only exist for milliseconds is hardly useful is it? The bad old days they doubled it again to (PMPO)- again meaningless.

Hypex are playing dissipation games, both in the SMPS supplies and their amplifier modules, so they are keen to embrace their own arbitrary period where they can extract more power from the combination before either one, or both modules thermally limits and/or shuts down. They appear to be calling short term continuous (ever a misnomer if there was one)- peak power, where they get to specify the length of the short-term nature to suit themselves. Then sweep it all under the carpet with the old chestnut about 'the dynamic nature of music'.

 

[restorer-john]

What I measure is constant although I don't let it sit and do that for minutes or hours.

No less than 5 minutes for continuous, Amir. That is the standard. If some piece of HiFi amplification cannot handle 5 minutes at rated power, it is rubbish and should be called for what it is.

 

[Sylafari]

Let's say I wanted to use these with my brand new spanking Revel M126Be's... would they be a good choice?

 

[Sancus]

If the standard is 5 minutes, according to Hypex themselves, the SMPS600 can handle 200 wpc. Even if you need to feed 25wpc(1/8 400) into it for an hour first, it seems likely that it would substantially exceed the 75wpc "continuous" rating in the datasheet, if the 5 minute rating is correct. Overall, I'm not sure why we'd perform this testing on a DIY amp that was deliberately built "underpowered" rather than a Hypex-based amplifier from a commercial manufacturer with actual ratings for the entire unit.

You can't really find out the limits of the NC400 module by testing this unit anyway.

 

[restorer-john]

You can't really find out the limits of the NC400 module by testing this unit anyway.

The NC400 amplifier module is specified with the SMPS600 power supply that was supposedly designed for the NC400 amplifier.

Test it one channel driven and confirm performance. How hard is it?

 

[Armand]

The NC400 amplifier module is specified with the SMPS600 power supply that was supposedly designed for the NC400 amplifier.

Test it one channel driven and confirm performance. How hard is it?

The result is given. The SMPS600 will overheat. Even a SMPS1200 will be come very warm after a few minute while maxing a NC400.

 

[Sancus]

Test it one channel driven and confirm performance. How hard is it?

I agree testing to see if it meets its own specs is reasonable, if it doesn't meet them, that would be good to know.

The result is given. The SMPS600 will overheat. Even a SMPS1200 will be come very warm after a few minute while maxing a NC400.

According to the SMPS600 documentation which was already posted in this thread it's good for 400W(2x200) for 5 minutes, which would meet both the FTC test and also the "400 watt" rating of the NC400.

If Amir is really afraid of damaging it, even a 300W for 5 minutes test would be well within safety margin of Hypex's spec. And according to the datasheet, the unit also has a thermal cutoff at 95C heatsink temperature, so it shouldn't be that unsafe to test it to overheating.

 

[restorer-john]

As an analogy, if this stuff is turbo-charged 4 cylinder pocket-rocket type amplification, the limitations will be plainly obvious, just like when you hit the hills with 5 passengers, towing a heavy trailer or caravan. They overheat and give up. That's where V8 or diesels can go all day without a hitch.

In Australia, nobody tows a caravan long distances without a diesel or a big V8. If you just want to zip around town impressing your mates with how fast you can sprint from one traffic light to the next, you get the equivalent of an nCore.

 

[restorer-john]

And according to the datasheet, the unit also has a thermal cutoff at 95C heatsink temperature, so it shouldn't be that unsafe to test it to overheating.

They'll be fine. Most semis are rated to 150 or 200 degrees C junction temperature (obviously derated) in operation. Consider they were preheated to probably 300 degrees C before going through the solder wave/oven at over 400 degrees C. (pbfree)

 

[March Audio]

As an analogy, if this stuff is turbo-charged 4 cylinder pocket-rocket type amplification, the limitations will be plainly obvious, just like when you hit the hills with 5 passengers, towing a heavy trailer or caravan. They overheat and give up. That's where V8 or diesels can go all day without a hitch.

In Australia, nobody tows a caravan long distances without a diesel or a big V8. If you just want to zip around town impressing your mates with how fast you can sprint from one traffic light to the next, you get the equivalent of an nCore.

Interesting analogy but not quite correct imo. Towing a caravan is an example of real world use. Continuous sine output is not. Music is very much "zip and sprint" as you put it. Rms levels, even in compressed rock, are typically only 1/5 to 1/8 peak.

That's not to say we don't need test regimes to evaluate and compare, we absolutely do. However to say an amp needs to continuously deliver rated power to be any good would be misleading.

The FTC test places a time limit of 5 mins, seems reasonable, but even that bears no resemblence to real world use.

I hope those damn Resistors arrive tomorrow

 

[amirm]

I will need owner's permission for any extensive testing....

 

[restorer-john]

...I hope those damn Resistors arrive tomorrow...

As I think I've said before, you can always head down to the local appliance store and buy a few cheap 1900W electric jugs, fill them with water and away you go.

Bonus: you can make a cup of tea after you're done.

 

[restorer-john]

Just for fun, just now, tested my kettle here, 2054W at PF 0.99 at 239V. 8.59ohms. Pretty darn close for a free 2KW water cooled dummy load sitting on my kitchen bench!

I do know a bloke who has 4 matched resistance kettles to to test high powered PA amps. Apparently he went through all the kettles at his local appliance store with his DMM to get perfect 8 ohm ones (rated 1900~ watters).

 

[March Audio]

Just for fun, just now, tested my kettle here, 2054W at PF 0.99 at 239V. 8.59ohms. Pretty darn close for a free 2KW water cooled dummy load sitting on my kitchen bench!

I do know a bloke who has 4 matched resistance kettles to to test high powered PA amps. Apparently he went through all the kettles at his local appliance store with his DMM to get perfect 8 ohm ones (rated 1900~ watters).

What's the inductance?

 

[dragonspit4]

This unit is slightly customized I believe, and is limited by the power supply (the 600 model he bought it for the monoblock unit, the 1200 model is for stereo use), but the super simple DIY kit that Hypex (monoblocks for <$1600/pair I believe) is a might more powerful, Datasheet with specs and graphs.

If you want an assembled unit, James Romeyn sells a stereo unit for $1500 I believe and a monoblock pair for $1900 I believe.

wow, that's very expensive!