Buckeye NC502MP 8-Channel Amp Review

[Julf]

Other than experience and a ton of explanations from experts like the one I posted,of course not.

The reason I am asking is that this is audio science review, after all.

The one thing not mentioned is that the article states that it doesn't matter where clipping occurs (can be before the amp),it's its shape that makes unproducable by the drivers and so converted to heat.

That is really a myth. Even when working perfectly, a driver converts 95-99% of the power fed into it into heat.

 

[Sokel]

The reason I am asking is that this is audio science review, after all.

That is really a myth. Even when working perfectly, a driver converts 95-99% of the power fed into it into heat.

It only takes a look at a clipped signal to at least see the duration of the flattened end,way more than the single peak of the normal signal.
This duration will translate to what?
I hope someone of our experts jumps in to give us a definitive answer.
As an example Amir's set-up has 1KW on tap,I don't think Revels can stand it for a long time and I don't think it was just a random choice of his.
Real world examples are the best when coming from people who know what they're doing.

 

[Julf]

It only takes a look at a clipped signal to at least see the duration of the flattened end,way more than the single peak of the normal signal.
This duration will translate to what?

It will translate into dissipated power and thus heat - just like with any other signal.

As an example Amir's set-up has 1KW on tap,I don't think Revels can stand it for a long time and I don't think it was just a random choice of his.

And my main system has 1200 W on tap. But it has to be used responsibly.

Real world examples are the best when coming from people who know what they're doing.

And knowing what you are doing is based on scientific understanding, facts and evidence. Unfortunately the audio world is full of all sorts of myths, fables and old wives tales, often based on a small ounce of truth but distorted and amplified beyond reason by people who don't understand the underlying reasons.

 

[Sokel]

Just for the fun of it I did a quick one:
Unclipped:


Clipped:


I think we can see what this article is about.
(I took care not to exceed 0db)

 

[Julf]

Just for the fun of it I did a quick one

Not sure what you are saying with those plots.

 

[Sokel]

Not sure what you are saying with those plots.

I think they are self explanatory.
What we see at the clipped signal still has to be reproduced by the drivers,even if we not exceed full power.
See the energy of the harmonics?See their levels?A little more and it would resemble a square wave!

No driver is happy with this,and that's ONE tone,right?Imagine with music.

 

[Julf]

What we see at the clipped signal still has to be reproduced by the drivers,even if we not exceed full power.

Right. The clipped signal looks very much like modern pop music.

See the energy of the harmonics?See their levels?A little more and it would resemble a square wave!

Have you actually analyzed the energy instead of just looking at how it looks? Even a pure square wave only has 40% more energy than a sine wave of the same peak amplitude - and that is assuming an infinite number of harmonics.

No driver is happy with this.

Any driver designed to cope with 30% more power than the peak power of the amp will be more than happy with that signal.

 

[DonH56]

All this clipping stuff should probably go in another thread...

There are at least three factors I can think about off-the-cuff to be wary of clipping:

1. Clipping moves from a sinusoidal'ish waveform (depending upon the source) to a square wave, changing the RMS value from ~0.7 (sqrt(2)/2) to 1, thus increasing the power delivered to the speaker by 40% or so.
2. Clipping adds higher harmonic content thus delivering more power to the tweeter. How much more depends upon the signal content and how deeply into clipping you go.
3. Clipping can cause instability in some amplifiers, or some amp/speaker combinations. May be only a little high-frequency ringing, but in the worst case causes oscillation and complete annihilation of the known universe. Or something like that.

FWIWFM - Don

 

[Doodski]

oscillation and complete annihilation of the known universe.

ad infinitum​

(Dang formatting won't go away so it's bold and it's big.)

 

[DonH56]

There is also this old thread about clipping: https://www.audiosciencereview.com/forum/index.php?threads/clipping-101.7164/

 

[amarsicola]

1. Clipping can cause instability in some amplifiers, or some amp/speaker combinations. May be only a little high-frequency ringing, but in the worst case causes oscillation and complete annihilation of the known universe. Or something like that.

FWIWFM - Don

"And all this clipping can produce a chain reaction and disrupt the space-time continuum ! I reckon this is the worst case scenario"
Dr. Emmet Brown

 

[EJ3]

The reason I am asking is that this is audio science review, after all.

That is really a myth. Even when working perfectly, a driver converts 95-99% of the power fed into it into heat.

I'll butt in at this point: Science coming up with a

theorem​

noun​

the·o·rem ˈthē-ə-rəm
ˈthir-əm

Synonyms of theorem
1
: a formula, proposition, or statement in mathematics or logic deduced or to be deduced from other formulas or propositions

2
: an idea accepted or proposed as a demonstrable truth often as a part of a general theory : PROPOSITION

Usually this is tested in some manner (based on EMPIRICAL KNOWLEDGE of what we know happens [or doesn't happen] to find out WHY it happen [or doesn't happen]) to decide is this theorem valid. So, in Sokel's testing of using more power on his particular speakers, that hasn't caused them to blow.
It may be that in order to blow them, he needs even more power.
But, as it stands, they haven't blown with the amount of power that he has used.
But it is known that a clipped wave will blow a tweeter at low wattage (and that has been proven).
And there is the case that too much power can blow a tweeter (which has also been proven.
In Sokel's case, he has proven that the amount of power that he is using won't blow his PARTICULAR tweeters.
So, know one knows how much clean power Sokel's tweeters can handle before blowing (but at some very high power level, they surely will).
It's just that no one knows what power level that will be at.
So Sokel's EMPIRICAL KNOWLEDGE (from [unintended, perhaps] scientific experimentation {will X amount of power blow his tweeter's) and the answer is No, that what he is doing, at the level that he is doing it, does no harm. That is scientific, as he performed an experiment and it gave him an answer.
Julf's Scientific argument is that Sokel just has not applied enough power for Julf's tweeters to blow. And is true also.
With all of this, I fail to see the issue. We know that clipping will kill a tweeter. And we know that extremely excessive power (even if it does not clip) will blow a tweeter. It is simply a matter of how much for whichever tweeter it is. But is is also proven that clipping will blow a tweeter at almost any power level, while it MAY take MASSIVE amounts of excess power to blow a tweeter. So, within the parameters of what is happening and what could happen, we know BOTH Sokel and Julf are correct. They should both know that also.
Again: What, exactly, is the problem here?

 

[sarumbear]

Just a small reminder - what burns speakers is not clipping, but too much power.

Wrong. Clipping creates more energy then high peaks - voice coil will heat more with clipped signal than a signal with high peaks.

 

[Julf]

Wrong. Clipping creates more energy then high peaks - voice coil will heat more with clipped signal than a signal with high peaks.

Yes. In absolute worst case, 40% more than with an un-clipped sine wave. So from that point, a 150 W amp not clipping is worse than a 100 W amp clipping.

That of course ignores the fact that the 100 W amp can produce much more than 100 W, and yes, there are amps that misbehave when clipping, even going into oscillation. That is a different discussion.

 

[ruzun]

Kind reminder: this amplifier clips when receiving more than 2.9V xlr.
If your DAC or preamplifier can spit out more than 2.9V and you (or your device) accidentally turn the volume all the way up, your speakers will get burned.

Do most amps have some protection circuitry that this amp is lacking? I have an Anthem AVM70 8K AV processor and it says:
PREAMPLIFIER (MEASURED AT XLR OUTPUT) Maximum Output (<0.1% THD) 10.7 VRMS, Subwoofer 11 VRMS

Does this mean this amp is not safe to run with my AV Processor? Do other amps protect against clipping when there is too much voltage?

 

[Julf]

Do most amps have some protection circuitry that this amp is lacking? I have an Anthem AVM70 8K AV processor and it says:
PREAMPLIFIER (MEASURED AT XLR OUTPUT) Maximum Output (<0.1% THD) 10.7 VRMS, Subwoofer 11 VRMS

Does this mean this amp is not safe to run with my AV Processor? Do other amps protect against clipping when there is too much voltage?

How do you protect against too much input voltage? By clipping the signal?

The right solution is getting your gain structure right.

 

[Buckeye Amps]

Do most amps have some protection circuitry that this amp is lacking? I have an Anthem AVM70 8K AV processor and it says:
PREAMPLIFIER (MEASURED AT XLR OUTPUT) Maximum Output (<0.1% THD) 10.7 VRMS, Subwoofer 11 VRMS

Does this mean this amp is not safe to run with my AV Processor? Do other amps protect against clipping when there is too much voltage?

I run the AVM 70 8k with NC502MPs.

For you to apply too much voltage, you would be turning the volume up to a level that your hearing would find uncomfortable or that your speakers wouldn’t be able to handle.

 

[Bassman999]

Even high end AVR's cannot come close to what this can do. Try running 11-13 channels of hard to drive 4ohm speakers at reference level. Not everyone will need this but those that do, or want something like this to never have to worry about having enough power, it is a great option. Also, not everyone uses an AVR and use processors instead.

Yeah I have 2 Denon AVRs and still plan to upgrade.
First of all the 105 watts x7 Denon shows is with only 2 channels driven. They dont have nearly enough PSU to run them all close to that.
Also 100 watts inst much, Id rather have 300+ watts and never need to use all of it, than worry about distortion and poor dynamics.
I have blown speakers with too little power (clipping), but as yet none with too much power
Also I love the simplicity of repair with a dedicated amp.

 

[Sal1950]

The second day after I volunteered to enter the US Army, the gave me a good clipping.
That was not a pleasant experience. LOL

 

[laidick]

would there be any issue if I place this in vertical instead of horizontal?