Hypex Ncore

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Hmm, why is Hypex recommending such high drive impedance one wonders?

Actually I had to go back and check the data sheet, as I couldn't remember anything about a minimum source impedance - and I am driving my nc400's with a much lower impedance source.

The way I read it, the *maximum* source impedance should be 1k, and even that is only in order to achieve the specified SNR (as higher impedances imply higher thermal noise).

So, Bertel, forget about those 1k resistors!
 
the *maximum* source impedance should be 1k

Hmm, you're right - in table 5 in the datasheet the '1' is in the 'max' column. But then I don't understand the comment part 'otherwise higher is fine'... Maybe that means although a max of 1kohm is recommended, you can have more without causing problems to NC400 but then won't meet the rated noise performance.
 
I just wanted to say, nc400 works great with MSB Analog Dac too (with Diamond Power). I am thinking of changing the DIY nc400 to a commercial product. Those nc1200 based amps are really hard to find for testing (none here in Finland i believe), but Bel Canto (REF600M) has some offerings with the new "not so expensive" nCore OEM module and NAD has the M22. The interesting thing is the different input stages, which makes some room for standing out commercially.

Any idea of those?
 
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I just wanted to say, nc400 works great with MSB Analog Dac too (with Diamond Power).

Good to hear!

I am thinking of changing the DIY nc400 to a commercial product
Just curious as why you want to do that? I don't think you'll get any real improvement in sound quality, and you would pay a lot just to get a more professional-looking box (that anyone can buy, unlike something you can be proud of having assembled yourself).
 
Just curious as why you want to do that? I don't think you'll get any real improvement in sound quality, and you would pay a lot just to get a more professional-looking box (that anyone can buy, unlike something you can be proud of having assembled yourself).

Well, i think the different input stages and tweaks can make a difference. Not necessarily better objectively (measurements), but maybe better for me subjectively. At least i want to test my theory. And I also want the professional looking box and a device without calibration potentiometers (that i know of) and internal cabling soldered by a professional. I got 28ke speakers and 18ke DAC/Pre. Maybe its time to move on from DIY all together.

I'll still keep the nc400 tho...it will be my trusty reference and backup. I am not too proud of just assembling an nc400 amp. The effort is quite minimal. I have assembled many devices and it's not that big deal for me. The proud feeling belongs to Bruno. He's the one that should be proud. He has done all the hard work.
 
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Well, i think the different input stages and tweaks can make a difference. Not necessarily better objectively (measurements), but maybe better for me subjectively. At least i want to test my theory.

The danger is that theories like that tend to be self-fulfilling.

And I also want the professional looking box and a device without calibration potentiometers (that i know of) and internal cabling soldered by a professional. I got 28ke speakers and 18ke DAC/Pre. Maybe its time to move on from DIY all together.
Fair enough. That is a personal choice. I am always sorry to see someone give up DIY for something anyone can buy off the shelf, but I guess that that just reflects the fact that I am a grumpy old man detesting the "I am what I buy" world we live in.

I am not too proud of just assembling an nc400 amp. The effort is quite minimal. I have assembled many devices and it's not that big deal for me.
True - but even then, there are people who pay others to assemble the amps for them.

The proud feeling belongs to Bruno. He's the one that should be proud. He has done all the hard work.
Absolutely! Hear hear!
 
Hello Hypex fans

Are there any rumours of newer modules coming out to supersede the nc400 modules?

Am seriously considering buying a pair of Stereo casings from Ghent ghentaudio --- Hypex & NCore NC400 NC1200 Stereo Case-kit and 4 x nc400 + 2 SMS1200 for BiAmping my new Monitor Audio PL200 speakers.

There are also the JOB 250 Monoblocks to consider which may sound better than the nc400 BiAmp config, or even a pair of JOB 225 for BiAmp?

Really difficult deciding on a route to take as I can't demo/compare - nc400 looks much nicer (in the Ghent cases) and power efficient than the JOBs, which look disgusting to my eyes, no offence meant to JOB Owners ;-)

...does the WIMA Capacitor mod really take the nc400 up to the next level (like the acclaimed airy JOB sound), or is this just hype/snake oil subjective, if anyone has compared or owned both?

Honestly, I would love one of John Westlake's limited edition VFET amplifiers and just be happy forevermore, but £3500 is just too much for me at the moment.

Many thanks!
 
Bridged NC400 Questions

Hello,

I currently own X 4 NC400 & X 4 SMPS600 modules and run them in a Dual Mono Chassis/Configuration. Up to this point I have had no reason or need to attempt to bridge the amps as I am perfectly happy with the power they provide unbridged.

BUT.....

An opportunity may be presenting iteself in the near future for me to upgrade my current speakers with something else. My current speakers are B&W 803 Diamonds (latest version) which allow for Bi-Amping. If I moved up within the B&W 800 series then this post would not be needed as I would continue to run the next model in the same configuration but I am also keeping my options open with other brands of speaker.

The problem is that most of the other brands of speaker I am looking at do not support Bi-Amping and only come with X 1 pair of terminals on them.

This brings me to my question. Since I would like to continue using my current Amp hardware I would then need to considering bridging them if I ended up choosing a speaker that doesn't support Bi-Amping. I have read and looked over the Hypex UCD documentation which talks about how to go about bridging the amps but unfortunatly I am still left a bit confused on the wiring aspects of doing this.

I have created the following caveman drawing below of what I understand needs to be done to accomplish this task and was hoping some folks here who are familiar with the process can maybe help guide me down the right path.

A few questions:

1. In terms of wiring the Input of one of the Amp modules 180deg out of Phase from the other does anyone know if it matters which Amp module in a given chassis should be wired this way? In the drawing below I have choosen to wire the module on the right which is destined for the "Positive" terminal of the speaker binding post out of phase. Is this OK or should the Amp module going to the "Neg" terminal recieve this configuration instead?

2. As an alternative, I was curious to know if there would be any difference if I choose to instead handle the Out of Phase wiring of the XLR at the cable itself. In other words, if I didn't touch any of the internal amp XLR wiring and instead aquired an XLR cable that goes from the Preamp to the Amp which was terminated in such a way that it would make Pin # 2 & # 3 swapped within the that cable instead.

3. In terms of the Output cabling that is supposed to have a 150nF cap inline, does the length of cable used in that connection matter? Would a cable as long as the one in the picture (lime green) have any negative effects? Should it be MUCH shorter?

4. In the digram I have the "J6" connection on both modules as the primary output wires going to the terminals for the speakers. At the same time I have "J5" going to chassis ground. Does this look right?

Thanks for any info or guidence you can provide.

An externally hosted image should be here but it was not working when we last tested it.
 
...does the WIMA Capacitor mod really take the nc400 up to the next level (like the acclaimed airy JOB sound), or is this just hype/snake oil subjective, if anyone has compared or owned both?

I have not seen any objective evidence for the claimed improvements.

Honestly, I would love one of John Westlake's limited edition VFET amplifiers and just be happy forevermore, but £3500 is just too much for me at the moment.
I don't see any reason you wouldn't be happy for evermore with the nc400 as well... :)
 
1. In terms of wiring the Input of one of the Amp modules 180deg out of Phase from the other does anyone know if it matters which Amp module in a given chassis should be wired this way? In the drawing below I have choosen to wire the module on the right which is destined for the "Positive" terminal of the speaker binding post out of phase. Is this OK or should the Amp module going to the "Neg" terminal recieve this configuration instead?

It only matters if you care about absolute polarity (you shouldn't).

2. As an alternative, I was curious to know if there would be any difference if I choose to instead handle the Out of Phase wiring of the XLR at the cable itself. In other words, if I didn't touch any of the internal amp XLR wiring and instead aquired an XLR cable that goes from the Preamp to the Amp which was terminated in such a way that it would make Pin # 2 & # 3 swapped within the that cable instead.
It doesn't matter where you make the phase inversion as long as you do it somewhere (and only once).

3. In terms of the Output cabling that is supposed to have a 150nF cap inline, does the length of cable used in that connection matter? Would a cable as long as the one in the picture (lime green) have any negative effects? Should it be MUCH shorter?
I would worry about it forming a loop that picks up stuff. Would it be possible to rotate one of the amp modules so that the output terminals would be closer to the output terminals of the other module?
 
Hmmm?

I have not seen any objective evidence for the claimed improvements.

I don't see any reason you wouldn't be happy for evermore with the nc400 as well... :)


Julf: Interesting, would you not consider the lower ESR and DA of the polypropylene caps used in the mod versus the OE caps to be objective? It is pretty standard practice for polypropylene film caps to be the preferred choice over mylar film in signal path applications, and I thought this was specifically because polypropylene film caps outperform (objectively, measured difference in DA and ESR) mylar film.
If you require actual measured difference in the output of the amplifier itself to consider it objective, this would be very hard to do, as it would require time domain measurements of some type to assess the different memory effect of the caps involved: I suspect that measuring these differences would be possible, but very, very difficult, and require something more than even what an AP-2 is capable of.

To consider: how many speaker builders would expect the highest level of performance when using a mylar film cap in the crossover versus polypropylene film?
 
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