@fabien44
my reply is not to argue.
Just I have a pair modified and a pair stock I have lived with the stock units along time now and I know there sound.
Nothing in an SQ is less in the modified units and the gains don’t over power any range low,mid,high that I discern from the music, it is more enjoyable musical and balanced.
I would say to the manufacturer put in place the modified pair and compare with the ear to the stock unit and tell us it sounds less musical, I know which will win for certain. I spoke earlier with supporters of Hypex to be advised leave perfection alone. I am a Hypex supporter, fortunately too I have a background in electronics and an experimenter at heart, see I’m an old ham radio operator whos happy to experiment when a situation looks good the caps looked to good to pass up.
Don’t do it if you are not willing to take a chance as I did, each system is unique. and it sings in my system, I would expect it to do the same in others, but that is unknown till you try in your system right 8-> . If you lived in NZ and local enough I would be happy to bring my amplifier to you if you had the NC400 to compare
Cheers
John
What is the function of these capacitors?
Output coupling capacitor
This sums it up well I think
Audio is a form of AC which is amplified by the amplifier and finally fed in to the speaker. As the various stages of the amplifier are powered with DC it is mandatory to block the Dc and take the audio component for processing. And various capacitors are used to transfer the audio separated from DC
@johno
Thanks John for your invitation but i live in France. I would like to visit your beautiful country 
maybe one day.
And what do you think about others Ric’s mods ?
http://www.audiocircle.com/index.php?topic=110782.0
johno said: This sums it up well I think
Yeah, absolutely... :-/
@fabien44
At this stage I have found amazing amount of space/reverb/air way more music I’m hearing highs which I have not heard previously, then I pay attention more specifically to the Bass and yes still there deeper and more defined.
I will enjoy this awhile, my short term plan involve spinning the NC400 180 degrees and shortening all the wires and feeding the connecting power from the SMPS600 outside the cabinet then back into the case at the point of entry for the NC400 also partitioning off the NC400 and SMPS600 from each other with a metal wall. the outside the case power cable will also be surrounded by a metal shield.
those are my mods,
Now for the remainder of Rics mods cant say till you try them out, I may not do any more than what I have outlined above, time will tell. no long term plans but waiting for WaveStream ability to play all resolution 
I haven’t had the luxury to hear a better sounding system than my own presently, I would like to hear some better and that may drive me to search for more than I have, though that will be $-)
@johno
From your point of view, what are the amps in the market that could compete with your modified NC400 amp?
Ric told me now that NC400 is now obsolete and outrivaled by new product like Job 225 amp. He wants also mod this one.
I can’t say enough good about the (stock) Job 225! Have owned it now for about 3 months. And it smoked 2 previous, similarly-powered, current-model, highly-thought-of amps of mine that retail for 3 and 4 times as much. Need I add that I have never looked back?!
And the Job is reasonably priced in addition to being a great value.
Job is more valued than NCore?
I don’t man to say I have the best sounding amp there just that I have and I’m certain there is way better and the best may always be beaten.
Just that I’m extremely satisfied at the level of sound now, I’m very satisfied.
I would need a whole new listening room to get extremely serious and big dollars to change everything and that I don’t have.
I don’t believe Ric modified his NC400 with all three caps!
@rlabarre
It is my opinion the stock amp sound is held back from fully expressing itself without the cap mod. there is better sound in the NC400 to be heard
I don't believe Ric modified his NC400 with all three caps!
Yes, i think he changed one cap, for you it's better to change all three?
Yes I believe this is the case, replace all 3
1. All Caps the same type
2. Foil to ground
3. No steel leads - all copper leads
@johno@datacom.co.nz
Johno, my friend Dave at P.I. audio built my NCore 400 and did partitioning, this might be of interest to you.
http://www.audiocircle.com/index.php?topic=106187.420
Here are his comments on the design.
First, the ERS cloth. ERS is the weirdest material that I have ever worked with and defies explanation and goes beyond logic in some ways. Why does a material that works solely in the RF region sometimes have an obvious effect and sometimes not? That is a hard one - suffice to say that it just does. Is it ever a profound effect? Nope, at least not to my ears. Remember that I am a hard core subjectivist when it comes to audio… a recovering hard core objectivist. There are some things that I have just quit trying to wrap my inquisitive head around and recognize that they “may” or “may not” have a beneficial effect in a particular application. It is an instance of what our Aussie friends call “suck it and see” or as we say, “give it a try.” ERS was used in my first BUSSes, but not in the recent ones. Why? Because I changed some materials in the newer ones that eliminated the need for ERS.
So, why does ERS work in this application? Because it does, that’s why. I tried it with and without in several different configurations and ended up with about half of what is seen in the picture. It is located only over the SMPS. Like I said, the soundstage was better with the ERS than without and better as I reduced the size to what it is now. ERS is like gravity: it works and part of it can be measured and quantified, but in the final analysis, we still don’t fully understand it. ERS is NOT like gravity in the context of constant functionality. Gravity is pretty much a given.
This brings us to the real topic of my missive here and in my business as well as my life. I loathe and detest noise. From the noise on the street or in a restaurant, to the RFI that plays hell with good audio reproduction, noise sucks. In audio, noise sucks power from amplifiers, clarity in all kinds of circuits and life out of the music. To prove a point many years ago I bought two of the same portable boom boxes. In one of them I went on a noise hunt. Took months. From the power supplies to resistors, to cabinet damping I searched for everything that was a noise contributor. In the end, there was no sonic comparison. The boom box became a reasonable source for music. I still use that sucker in my garage. Sounds awful now due to age, dust and abuse, but it serves to remind me of why I do what I do.
On to Roger’s amp. I decided that I would build him an amp in the way I would build it for me, not just do an assembly job. That meant that I would employ every technique that I know to eliminate the SMPS noise form the amp (within reason). I’m a wood butcher. I don’t have access to machine tools or the talents of Matt Kramer or Jason to do what they do, I had to go with what I know. That is: noise reduction; layout; cryo and common sense.
Cryo - cryo is like a good chiropractor. it removes tension and stress in the materials. There are also changes to the materials on a molecular and crystalline lattice/boundary level that are well documented and don’t need explanation here. Cryo works. Accept the fact… it just does. I cryoed the guts of the amp. Everything I put in my products is cryoed. It’s like chicken soup - couldn’t hurt. I’m a CryoGuy to the max.
Noise reduction: I approached this from two directions - compartmentalization and shielding. The mu metal and copper foil shield was used to provide as much ground plane shielding as possible. I wired this as a Class 2 device with the earth (ground) unattached to the chassis. All of the shielding is attached to earth. Having everything grounded to a common point with a SMPS is a great way to make a tiny radio station out of the ground plane. YMMV. I’m just sayin’. Try running down a problem in the D-ground in a recording console sometime…
Having established the two compartments, I twisted the cabling and used copper foil to shield the wiring. I twisted the wiring for the two SMPS in opposite directions because it just makes sense to do so and takes no additional time. Mutual induction is probably not an issue with this layout, but why not just do it? I kept everything that had to do with power in the power compartment as much as possible.
On the amplifier side of things, I simply kept everything as short as possible and added a bit of additional shielding here and there.
NOTE: I really, really don’t like the signal cable used in the Ncore kit. In the future I would change that wiring out to something more substantial and user/builder/sonically friendly.
NOTE: the guy that thought that super bright blue LEDs would be a good idea should be… (insert your option here) I eventually ended up installing a back lit switch on the front panel for Roger.
On the power inlet side, I went with a Furutech gold plated power inlet because I like them and they “sound good” - yeah, I know… better than the power inlet used in the plans.
I’m not a scientist, just an audio guy. I build the way I build because I have found it to be the best sounding way to do things over many years of experience.
@rogerdn
Appreciated I will follow up on some of these topics you mention in future days, there could be benefits for me doing so thanks
Yes your NC400 build looks very nice replace those caps and you will be happy you did so
Where I can I like to directly solder cables silver wire and solder is the preference
Thanks Again
Cheers
John
Get the rest installed John?
Waiting for the caps to arrive, and the swap out will be done - there is no doubt. I have been away a few days so hope they have arrived by the time I get back home
Ric was running low on the WIMAs when I talked to him. Hopefully he had enough or had already sent yours by that time.