BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Review

[peng]

I agree continuous is a vague term but 1200 VA does not necessarily stands for 1200Wrms. In amplifiers rated for 2 x100w @ 8 ohm transformers rated at 300VA and even less are common place.

Also bridging BTL is commonly used as an easy trick for increasing the output voltage swing X2, allowing claims for power increases X4, and even more as impedance falls at 4,2 and even 1ohm (car audio) , but then continuous use is almost always seriously compromised.

I have been reading the datasheet of the NC500 and It clearly mentions a peak power of 700W @ 4 ohm, but also a ratio of 1/5 from continuous to peak power. Rms power is only rated at a modest 100w.

For me as a home user, It is great because It allows an headroom i could not imagine, but for PA use it means you are constantly at risk of something going wrong.

I simply refer to the posted specs that says 1200 VA transformer and 1200 w power consumption.

The posted specs also cover power output into 8,4.2 and 1 ohms, those numbers seem achievable for a 1200 VA power supply for a class AB amp.

 

[ClaudeJ1]

Agree with horns (and favours of the recent generation of Class-D), but not with splitting hairs: specs should be reliable for customers. If specs give overestimates of power misfailure can be foreseen.

I disagree. ALL Amplifiers should be rated in DBWatts, not Watts. But the Marketers always win over the Engineers, period. The difference between, say, 350 watts and 400 watts is only 0.58 db, which is undetectable by anyone. Even those who claim to have "golden" ears. So I call Bovine Sediment on the whole issue. Get more sensitive speakers with more pro drivers is the answer to full dynamics. Simple. Quit buying all these Direct Radiator Space heaters the create 1,000 time the IM distortion as amplifiers. Something no one ever talks about.

 

[ClaudeJ1]

that doesn't do anything for bass and that's where almost all my wattage goes - below 40hz

Sub bass is a different animal that does not need amp measurements to 20 Khz. either. Balderdash, I have 5 tapped horn and full horn Subwoofers that can handle 24-30 db watts of power with sensitivities ranging from 100-106 db/w. I use the cheapest class D Behringer 800 on them (also have a JBL Bass Relex Theater Sub). Go big or go home if you want real performance instead of your typical mini sub with 50% distortion at theater levels. Get a new wife or Girlfriend who loves music and good sound if need be. LOL.

 

[ClaudeJ1]

that doesn't do anything for bass and that's where almost all my wattage goes - below 40hz

Hey old lady watch your mouth.
I don't care about your history class and gratitude towards technology.
Amp should not die, Period.

Agreed, but any device can be pushed to the point where it will fail. Should we use YOURS to prove that point? Also, don't mess with old ladies, they know more than you do and don't really care what YOU care about either.

 

[Salt]

I disagree. ALL Amplifiers should be rated in DBWatts, not Watts. But the Marketers always win over the Engineers, period. The difference between, say, 350 watts and 400 watts is only 0.58 db, which is undetectable by anyone. Even those who claim to have "golden" ears. So I call Bovine Sediment on the whole issue. Get more sensitive speakers with more pro drivers is the answer to full dynamics. Simple. Quit buying all these Direct Radiator Space heaters the create 1,000 time the IM distortion as amplifiers. Something no one ever talks about.

What's Your diagree over 'specs should be reliable'?

 

[Doodski]

I disagree. ALL Amplifiers should be rated in DBWatts, not Watts. But the Marketers always win over the Engineers, period. The difference between, say, 350 watts and 400 watts is only 0.58 db, which is undetectable by anyone. Even those who claim to have "golden" ears. So I call Bovine Sediment on the whole issue. Get more sensitive speakers with more pro drivers is the answer to full dynamics. Simple. Quit buying all these Direct Radiator Space heaters the create 1,000 time the IM distortion as amplifiers. Something no one ever talks about.

How is dBWatts calculated or found?

 

[ClaudeJ1]

What's Your diagree over 'specs should be reliable'?

10% should be close enough. Just like TSP's on drivers. Real world loads are NOT resistors, so a little headroom is nice, just in case, but the Marketers push the highest pulished numbers possible, until Industry Standards are established and adhered to, and even then......................I remember 200 watt P-P (peak to peak) specs. (15 W RMS) when I was a kid. At least now were are much closer to the truth, and appreciate Amir for it.

 

[ClaudeJ1]

How is dBWatts calculated or found?

db Watts= Watts LOG x 10 on calculator. 0 db Watts is 1 watt, 10 dbWatts is 10 watts, 20 db Watts is 100 Watts, and 30 db Watts is 1,000 Watts, 40 db Watts is 10,000 Watts.

Just add db Watts to your Speaker Sensitivity, say 90, with a 100 watt amp is 90 + 20 + 110 at one meter, minus 10 db or so to your listening position will get you 100 at your seat at full output plus another 3 db for the other channel. Simple.

 

[Doodski]

I disagree. ALL Amplifiers should be rated in DBWatts, not Watts. But the Marketers always win over the Engineers, period. The difference between, say, 350 watts and 400 watts is only 0.58 db, which is undetectable by anyone. Even those who claim to have "golden" ears. So I call Bovine Sediment on the whole issue. Get more sensitive speakers with more pro drivers is the answer to full dynamics. Simple. Quit buying all these Direct Radiator Space heaters the create 1,000 time the IM distortion as amplifiers. Something no one ever talks about.

I found the dBWatts Wiki. It seems the scale of dBWatts is very coarse and not high resolution. very close dBWatt numbers would make things tricky.

 

[ClaudeJ1]

I found the dBWatts Wiki. It seems the scale of dBWatts is very coarse and not high resolution. very close dBWatt numbers would make things tricky.

No it isn't if you carry your calculator to 2 decimal places, you can get fractional (decimal) db Watts no problem which is beyond human hearing resolution of 0.1 db.

 

[Toni Mas]

I found the dBWatts Wiki. It seems the scale of dBWatts is very coarse and not high resolution. very close dBWatt numbers would make things tricky.

Btw 10db more, or X10 W more, only sounds twice as loud. This also explains why some guys can be happy enough with 50w or less while others need 500w.

 

[Ron Texas]

These Hypex and Purifi amps measure amazingly well. The question is, does this NCx500 sound better than say a NC502 or even an NC252 if one doesn't need the extra power? Someone around here did some testing and asking around and found a SINAD of 72 dB (complete signal path) was enough for most people and 78 dB for a few. My take here is there are limitations on passive speaker performance, typical room acoustics and our hearing which are coming into play. I also recall that in a teardown of a renowned active speaker at ASR the chip amp in the unit had a SINAD of around 75 dB. It's the old question, how good is good enough.

I will freely say that a higher SINAD is evidence of better engineering and execution.

 

[Toni Mas]

I will freely say that a higher SINAD is evidence of better engineering and execution.

I am also surprised by the importance given to SINAD.

Does noise really matters so much? For low level signals in preamps or dac, It obviously does. In a power amplifiers, isn't noise simply almost a measurement artifact?

The weighting of H products seems to be also totally forgotten. Low order products like H2 or H3 do really deserve to be given the same importance as high order ones?

 

[ClaudeJ1]

Btw 10db more, or X10 W more, only sounds twice as loud. This also explains why some guys can be happy enough with 50w or less while others need 500w.

50 Watts is 16.99 dbWatts.

 

[Toni Mas]

50 Watts is 16.99 dbWatts.

And 500 w are almost 27. Need twice to get 30. But wont be twice as loud.

 

[xaxxon]

Agreed, but any device can be pushed to the point where it will fail. Should we use YOURS to prove that point?

I've spoken with the guys at benchmark a few times, they don't seem concerned about their AHB2 breaking under stress. And they're clear about under what loads it will protect under and why they do/don't advertise certain numbers.

But that's a very different price class than this product (though not exceptionally expensive in the overall space of audio amplifiers at $3k/channel for 500wpc)

 

[MaxwellsEq]

Does noise really matters so much? For low level signals in preamps or dac, It obviously does. In a power amplifiers, isn't noise simply almost a measurement artifact?

After frequency response, noise is the most important measurement. But SNR is relatively unhelpful, a single number such as residual noise output voltage or noise output voltage is more helpful, since it eliminates gain from the equation. You will notice that the lower gain amps often have better SINAD - there is a reason for this!

 

[Toni Mas]

After frequency response, noise is the most important measurement. But SNR is relatively unhelpful, a single number such as residual noise output voltage or noise output voltage is more helpful, since it eliminates gain from the equation. You will notice that the lower gain amps often have better SINAD - there is a reason for this!

Yes sure but with tube amps for example you might have PSU noise, it even might be sightly audible, but maybe too you dont pay any attention, though the measurements will be criminal. On the other hand you begin to play changing tubes and you will hear different types of distortion, some you will like better, some you will find worse, regardless of the measurements. So why bother so much with sinad?

 

[MaxwellsEq]

Yes sure but with tube amps for example you might have PSU noise, it even might be sightly audible, but maybe too you dont pay any attention, though the measurements will be criminal. On the other hand you begin to play changing tubes and you will hear different types of distortion, some you will like better, some you will find worse, regardless of the measurements. So why bother so much with sinad?

There's evidence that humans are relatively unable to detect quite high levels of distortion. There's other evidence that some humans like the effect of some distortion. There is some suggestion that certain types of distortion are equated with "increased" detail or "richer" soundscapes

BUT, why would anyone want an amplifier that is not engineered to minimise noise? There are many types of noise, but ultimately noise can set constraints on information transfer and retrieval.

 

[peng]

I am also surprised by the importance given to SINAD.

Does noise really matters so much? For low level signals in preamps or dac, It obviously does. In a power amplifiers, isn't noise simply almost a measurement artifact?

The weighting of H products seems to be also totally forgotten. Low order products like H2 or H3 do really deserve to be given the same importance as high order ones?

People probably think perhaps the reasons for the duts that don't do better than say, 90 dB SINAD on the bench is the more important point, especially for devices that cost more, even much more than devices that measured much better, for much less.

Someone may say it's negative feedback, but not for the likes of Hyex and Purifi, as Bruno Putzey debunked that excuse long time ago.