[Emile]

Listening, be it biased or unbiased aside, why would the nc1200's sound better then the NC400's.

Prequel: I own a pair of Spectron amps, there's no question, they are in a different league when bridged in my system.

I got the following from the Hypex datasheets, tried to match as best as possible but typical/maximal values are not all supplied, for power the NC400 has typical values and NC1200 minimal values for example, anyway:

NC400:
Rated output power (typical): 200/400/580
THD+N (max): 0.002%
Output noise: 23uV
SNR: 125 dB
Zout (max): 1mOHM
Current limit: 24A
Power supply voltage: 64V

NC1200:
Rated output power (minimal): 400/700/1200
THD+N (max): 0.004%
Output noise: 20uV
SNR: 128 dB
Zout (max): 2mOHM
Current limit: 38A
Power supply voltage: 84V

So separately from the powerratings the NC400 should have half the output resistance/double damping factor and half the THD+N but the NC1200 3uV less output noise and a 3 dB better SNR. Enough for the differences in "sonic performance"? I'd be enclined to say no. However supplied powerratings are quite different:

8 Ohms: 200W(typ) vs 400W(min)
4 Ohms: 400W(typ) vs 700W(min)
2 Ohms: 580W(typ) vs 1200W(min)

Voltage (times 93% efficiency): 59.52V vs 78,12V
Current: 24A vs 38A

V*A: 1428,48W vs 2968,56W

Now suppose we replace the NC400 with a bridged pair, we should get:
8 Ohms: 800W vs 400W
4 Ohms: 1160W vs 700W
2 Ohms: between 1160 and maybe 1682W (? no 1 Ohm rating supplied) vs 1200W

Voltage: 119,04V vs 78,12V
Current: 24A vs 38A
V*A: 2856,96W vs 2968,56W

Zout should double so this would then be equal, edit: probably higher because of additional resistance from a piece of wire needed for bridging.
Probably more noise generated from double smps/double ncore, but also noise cancellation from driving speakers balanced(bridged) which potentially may be a big benefit.

I'd say a comparison between bridged NC400's and single NC1200's is in order in both normal and low impedance speakers since I can clearly see the NC1200's outperforming single NC400's per Spectron example.

[cab]

You lost me with your last remark:


"I can clearly see the NC1200's outperforming single NC400's per Spectron example."

After your earlier state:

"Enough for the differences in "sonic performance"? I'd be enclined to say no."

[playntheblues]

Ditto what Cab said   

[Emile]

thats suggesting the "but the NC1200 3uV less output noise and a 3 dB better SNR" bit would not be the main reason for it sounding "much" better then the NC400. I am suggesting the increase in power is responsible. And then what would happen if you bridge NC400's..

[*Scotty*]

Assuming that both amplifiers are operated without clipping the output, perhaps the difference in sonic performance that is being observed does not lie the the specifications alone. These are, after all two different amplifiers, it is illogical to expect them to sound exactly the same.
Scotty

[Rclark]

Apparently Mgalusha has measured several nc400's and they are actually 240 watts at 8 ohms so your numbers are low,probably for both amps.

[cab]

I was told the following by Hypex when asked about the difference in sound being reported:

"When you use the NC1200 with our SMPS1200 and the NC400 with the SMPS600 there should not be a big difference.
What you need to know is that most OEM customers that use the NC1200 now use there own power supply."
 

[James Romeyn]

NC400/SMPS600 minimum impedance rating 2 Ohms.

Is the following true or false?

Two SMPS600 driving two NC400 bridged = minimum impedance rating 2 Ohms
One SMPS600 driving two NC400 bridged = minimum impedance rating 4 Ohms

I changed my speaker load from series (10.6 Ohm minimum, about 125W) to parallel (2.65 Ohm minimum, about 500W).  So far I changed only the center channel, and await new speaker wire to change the L/R.  Even with only the center channel changed, clean output levels remind me of AudioKinesis. 

Dynaudio drivers benefit by huge current/voltage reserves.  I wonder if performance would audibly improve with even more current and voltage. 

[Occam]

The 2 Ncore1200 based amplifiers that I'm aware of (available now, here in the States) are the Atsah and Merrill Veritas monoblocks which both use a SMPS1200 per NC1200. Both use the version with built in input buffers rather than implement their own buffers.

[Regnad]

Can someone please clear up the NC400 and NC1200 input differences.   The NC400 (which I have) is complete, does the NC1200 require an OEM-supplied input stage?    If not, why all the talk of it?    If so, what are the various options? 

Thanks.

[Barry_NJ]

Can someone please clear up the NC400 and NC1200 input differences.   The NC400 (which I have) is complete, does the NC1200 require an OEM-supplied input stage?    If not, why all the talk of it?    If so, what are the various options? 

Thanks.

I'm not an authority, but I believe that the NC400 input stage is integrated into the board and it would be difficult to implement a custom one, but that the NC1200 is somewhat modular in design and a custom input stage can more easily be implemented.

[*Scotty*]

Regnad, The design and the parts used in the input stage determine to a large degree what you hear from an amplifier. The NC 1200 as an OEM piece has the option to to be built with a custom input stage designed by the mfgr. or it can be used with a Hypex designed input stage that is specific to the NC 1200.
Scotty

[Rclark]

post 341:

Bruno-
"Since not every new reader has the patience to read the whole thread, let me recap the overall plan for Ncore. UcD is already rather good and certainly adequate for practically any application. It would make no sense to rush out and flood the market with Ncore. So we're reserving Ncore for high end companies prepared to give it the profile it deserves. The NC1200 is the platform for that, so it isn't sold freely. I'm saying platform because we're offering customization. One of class D's problems in the high-end market has been the perception that it's just the same module in different boxes. We'll make sure one company's NC1200 won't be the same as another's (although of course measured performance will be the same).

For the DIY market there will be an über-tweaked version called NC400. "

 
How does the performance of the NC1200 compare to the NC400?

Bruno-
"All the info you need is in the data sheets. The NC400 has somewhat lower distortion & output impedance than the NC1200 and it's got de luxe discrete input buffers. Otherwise the NC1200 has about 40% more voltage and current reserve and that's pretty much all. " - post 2325


 that diy thread has everything you could possibly want and more if you guys truly want to know all. Take the time to read it.

[dan92075]

And yet every single review of a NC1200 based amp is reporting better performance than the NC400

Perhaps it something other than distortion?

For example, it would be interesting to see phase response on the two amps.

A square wave test would be useful as well.

[Russell Dawkins]

And yet every single review of a NC1200 based amp is reporting better performance than the NC400

Perhaps it something other than distortion?

For example, it would be interesting to see phase response on the two amps.

A square wave test would be useful as well.

Maybe the significance of simply having more headroom overrides the theoretical superiority of the 400 suggested by its distortion figures.

[Emile]

Maybe the significance of simply having more headroom overrides the theoretical superiority of the 400 suggested by its distortion figures.

Exactly, but if this is the case a bridged pair of NC400's should sound even better then a single NC1200, atleast into a 4-8 ohm load and assuming 24A is a sufficient current limit, which it should be..

Apart from this, look at the 138dB supplied for an NC1200 with no input buffer, thats awesome really, I cant remember ever even having seen a buffer stage that can match that figure irl.

[munosmario]

Exactly, but if this is the case a bridged pair of NC400's should sound even better then a single NC1200, atleast into a 4-8 ohm load and assuming 24A is a sufficient current limit, which it should be..

Apart from this, look at the 138dB supplied for an NC1200 with no input buffer, thats awesome really, I cant remember ever even having seen a buffer stage that can match that figure irl.

Emile, bridging itself--first, as an added circuit and, second, as a way to connecting together parts that, in the first place, were not designed to work optimally in that manner (basically, only as separate channels)--is a compromised step backwards in hi-end audio design. Amp bridging usage is mostly for PA sytems and car audio. In car audio, it is a mandatory way to generate more voltage given the 12.6 volt (full charge) limitation of a car battery. It is also used as a way of getting more "stereo" power by non-critical Home Theater users--using idle channels out of a bridging enabled multichanel receiver/ampifier. 

But as far as I am concerned, with a few notable exceptions (come to mind the late Richard Brown's legendary and uber-scarce BEL1001 Mark V, whose extraordinary stereo SQ performance  actually improved in bridged mono), no respectable audio designer out there will use bridging as the best way of generating more headroom and maintain or, more importantly, improve overall sound quality accross the board. If the main problem with your speakers/system is headroom, then, in your particular situation,  bridging identically quality amps will be most likely an economically way to improve your particular system...but generalizing and proclaming that " a bridged pair of NC400s should sound even better than a single NC1200" is quite a stretch--possible, in the realm of wishful thinking, yes...but, an obvios logical conclusion in the realm of science, not necesarlily. Of course, you may be totally right and the NC400s could end up joining the BEL1001 Mark V as one more of those few notable exceptions...to Bruno's surprise, unless he already knows that but is hidding it to protect the marketing of his own Mola-Mola and other OEM NC1200 creations.

munosmario 

[passingthrough]

And yet every single review of a NC1200 based amp is reporting better performance than the NC400

Perhaps it something other than distortion?

For example, it would be interesting to see phase response on the two amps.

There's another factor that can (for most humans, always does) influence one's perception of sound quality and that is bias and expectation.  I am not saying that explains this reported difference between NC400 and NC1200 but it certainly is in play and could contribute to the degree of difference people think they hear.  We know this because that bias is absolutely there since it is a human being's brain doing the subjective listening.  Not one of us should think we are necessarily reliable observers of comparative sound quality differences, although most of us do.

So if I had an opportunity to listen to both, I'd make sure someone helped out so that I didn't know which was playing over many listening sessions while I take notes and record my preferences, and confirm that despite Bruno's suggestion to the contrary, there is a marked difference in sound quality between these two amps with most or all people happening to prefer the sound of the NC1200.

‎"The first principle is that you must not fool yourself--and you are the easiest person to fool."
-Richard Feynman

I know that many of you are shaking your head at this line of thinking because you know that you hear what you hear and that you personally would not let your biases influence your perceptions.   To head off any flames, let me reiterate that I am not saying that I think that listener bias is the reason for the sound quality difference being reported between these amps.  I am only saying that since it's not all that hard to control for this factor, I wish someone would do that when they report on the perceived sound quality differences.

[playntheblues]

This is an ultra simplified answer but cuts to the chase.  The loudest (most powerful) wins.   No one knows these amps better than Bruno and he has told us the difference, check Rclarks post.  More power, done properly always wins the contest.  This is why I have bridged 400's, you have more head room, authority, clarity, better control, dynamics and just plan more fun 

By the way my balance DAC / Pre just arrived last night so I will write a short review in a few days.  Also will have a single ended Lampizator 4.5 with remote volume for sale soon.

[jtwrace]

my balance DAC / Pre just arrived last night

Which one?