Hypex Ncore

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Out of curiosity, how hot is the SMPS heatsink?

Hifi2000 sells a much more ventilated cover, I will start with that and see what happens.

You can also try the technique shown here, with your current cover:
NC400 Cooling

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While we are at it, would someone know the exact reference of the female crimp terminal to use with the microfit molex connector 43025-1200 ?
I think it is the 43030, but several version exists:
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What is the AWG of the wire?

I would like to fit 2 (or myabe even 3) wires per connector, so if the original AWG is 24, 2 of them should fit no problem in the 20-24 AWG model...

Also, do you know if special tools are required to assembled those crimps, or will a simple crimp tool be sufficient?

Digi-Key Part Number
WM1784-ND - Crimp
WM2776CT-ND - housing.

The crimps are very small. You should use a crimp tool to make life easy. Since this is small, a cheap tool from ebay will do the job with some careful fixing after that. This will hold up to 20 AWG. Use 1 20 AWG or more thinner wires. However the crimped wire will not fit in the housing if too many wires are used. If not using the right crimp tool, finish with some solder to make sure the wires do not slip out and have a better connection.
 
I have had them running all night today playing low volume. The cases are very hot. I can hold my hand on them without pain, but it is hotter than anything I have had before.
I will check if Hifi2000 sells more ventilated top covers to this case (Galaxy Maggiorato with aluminium top/bottom)
The internal regulators are working in the nc400 because I do not have the smps600. So they are dissipating more heat than the in normal case.
Without the top cover it was not running hot at all.
Any other advice what I can/should do? I know theat many class-A amplifiers are running very hot, maybe it is ok?

With 2 amp modules you are generating twice the heat. This builds up the heat on the case and it has a harder and harder time getting rid of the heat. Hence the heat build up. Always vent otherwise you are looking at the greenhouse effect. holes at the opposite ends of the chassis, eg. bottom back, top front.
 
Digi-Key Part Number
WM1784-ND - Crimp
WM2776CT-ND - housing.

The crimps are very small. You should use a crimp tool to make life easy. Since this is small, a cheap tool from ebay will do the job with some careful fixing after that. This will hold up to 20 AWG. Use 1 20 AWG or more thinner wires. However the crimped wire will not fit in the housing if too many wires are used. If not using the right crimp tool, finish with some solder to make sure the wires do not slip out and have a better connection.

Thanks a lot!
I do have the crimp tool that Hypex seel.
Do you know the AWG of the original wires?
If they are 24 AWG I guess two would easily fit in that 20 AWG crimp...
 
grounding design

Can someone explains why J5 is connected to (1) - aka the grounding to the case? I notice the heatsink's surface does not conduct electricity but it is actually connected to the casing when screws are applied.
 

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My 3 monoblocks with bridged nc400 and SMPS1200A400, built by my friend Georg.

We have compared them against the standard nc400+SMPS600 in a dual-mono config today. The bridged ones sounds much more "alive", and they are not even broken in. The standard ones sounds flatter. Less dynamics.

The monoblocks has version 4 of nc400. The dual-mono has version 3. What was the changes made in version 4?


So it sounds like there were two big changes:
1) using SMPS1200A400 instead of SMPS600
2) bridging using two NC400s

Its not clear how much of the improvements you are reporting can be attributed to each change?

Also, out of curiosity, how obvious are the improvements you are hearing? Do you have to do repeated AB to identify the improvements or is it immediately obvious?
 
So it sounds like there were two big changes:
1) using SMPS1200A400 instead of SMPS600
2) bridging using two NC400s

Its not clear how much of the improvements you are reporting can be attributed to each change?

Also, out of curiosity, how obvious are the improvements you are hearing? Do you have to do repeated AB to identify the improvements or is it immediately obvious?

True. Version 4 of nc400 might also be a change?

We had to do repeated AB to make sure what we heard was "true". Some would say it was very little difference, other would say big difference. Subjective. Georg will now change is amplifier to bridged as well.
 
First listening impressions Ncores with W4S STP preamp

I had written in previous posts about my search of a preamp to drive my DIY Ncores. After some months of research I finally decided on Wyred 4 Sound's STP-SE which arrived from California two days ago. Although it is still in the break-in period I thought some of you might be interested in some first listening impressions.

Beforehand some words about why I chose the W4S. I was searching for a fully balanced design, which narrowed down the choice considerably. After reading many reviews and listening to Musical Fidelity's M6PRE in my system at home, which sounded great but slightly pumped up to me, I was considering either Auralic's new Taurus preamp or the W4S. Given that both weren't available for audition in my town (Berlin, Germany) and had both gotten very good reviews e.g. at 6moons, I chose the engineering concept that convinced me most. (thanks to Srajan Ebaen who had reviewed both of them at 6moons for his advice and insights)

The Auralic converts the balanced signal to unbalanced in order to pass it through the Alps pot while the W4S stays balanced all the way with a very elaborate attenuator realized only with relays and resistors, which was a point in favour of the W4S. The buffered/passive approach with the possibility to pass to active mode seemed also reasonable to me.

Two days ago finally the package arrived and I connected the W4S STP via balanced cables to my Ncores, sources being Squeezebox touch plus Metrum Octave DAC on the one input and Rega P3-24 record player via Ray Samuel's F-117 Nighthawk phono amp on the other.

In the first half an hour the preamp sounded a bit harsh and somewhat incoherent and the bass seemed a little overdamped, all of which got better very quickly.
After some 12 hours of play I can say that I am very satisfied with the sound. Compared to the Lehmann Linear headphone amp that I was using as a preamp before the STP draws a much wider soundstage. It is more transparent and the instruments are better separated. I use the STP only in passive mode, the volume level is usually between 10 and 20 with the Ncores and the preamp moves to active operation only when the volume knob is turned higher than level 63.

Albeit the passive operation the preamp sounds muscular and authorative, although thankfully not pumped up as the Musical Fidelity but rather neutral.
I had run the Ncores via the Lehmann previously with a Hypex Interlink connection that passed from the RCA of the Lehmann to the XLR of my Ncores. In this connection my loudspeakers emitted a very slight hiss that one could hear approaching the loudspeakers and with no music playing. In the new configuration this hiss is completly gone, probably due to the all balanced operation of the STP.

I find the STP to be a good match to the Ncores. W4S says they should settle in for some 200 hours and will get mellower then. Right now they are on the transparent and slightly leaner side of things, which is fine for me and makes me hear slightest flexations of voices in a manner I haven't heard before. Also cymbals are shiny and more noticable with a finer and better discernable texture and a clearer rythmic structure than before. Nevertheless the music is powerful and with lots of body also in the bottom end.

I am very impressed by the preamp and feel that it makes it far easier to hear the quality either of my Metrum DAC and my Ncores. Colour me impressed.
 
Silly question as i'm sure has been answered or done and silly because i'm sure it has very minimal effect, but has anyone upgraded the power wiring to the smps, and if so, how did you make the connection to the plastic connector that comes stock with the brown and blue wire?
Reason I ask is because I bought some bulk furutech cable to make my own power cords and have some left over. Hate to let it go to waste since it isn't enough to do anything with but figured I could use it for the interior power wiring of the amp.
 
Silly question as i'm sure has been answered or done and silly because i'm sure it has very minimal effect, but has anyone upgraded the power wiring to the smps, and if so, how did you make the connection to the plastic connector that comes stock with the brown and blue wire?
Reason I ask is because I bought some bulk furutech cable to make my own power cords and have some left over. Hate to let it go to waste since it isn't enough to do anything with but figured I could use it for the interior power wiring of the amp.

See here to see the way I did it:

Show Us Your Core-NCore!


Best,
Anand.
 
Nice, looks a bit risky but since I still need to replace the original mogami cables with the newer cables hypex sent me I will take a god look when I open the case up and see how do-able it is.

Another question for those much more knowledgeable than I. Currently I am running regular 12/3 SJOW power cords, I have the ground (earth), hooked up at my plug but at my amp inlet the ground is floating, it is not hooked up to anything.

My new cables have a ground wire plus shileding. I have made them so that at both ends (plug and IEC or in my case neutrik powercon) the shield is connected to the ground. Is there any problem with hooking the ground and power cable shield up to my ncore chassis? I have a equi=tech balanced power supply on the way and was told I may benefit from shielded cable. Should I hook up the ground at the chassis with the balanced power supply that my amps will now be plugged into so that it is continuous or should I leave it disconnected at the amp?

Edit - One other question, off topic from my above post. I have a little 120VAC to 9VDC transformer/rectifier in my amp for my SMPS standy circuit. The manufacturer of the amp recommends putting a metal oxide varistor on the "hot" side of the 120VAC feeding the transformer. Does anybody know what specs the varistor should be? I'm confused by what voltage and other ratings I should use. They also recommend a thermistor, i'm confused about what ratings that should be also.
 
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My new cables have a ground wire plus shileding. I have made them so that at both ends (plug and IEC or in my case neutrik powercon) the shield is connected to the ground. Is there any problem with hooking the ground and power cable shield up to my ncore chassis? I have a equi=tech balanced power supply on the way and was told I may benefit from shielded cable. Should I hook up the ground at the chassis with the balanced power supply that my amps will now be plugged into so that it is continuous or should I leave it disconnected at the amp?

Well, normally I would recommend not connecting the shield to the chassis - the shield will still work as long as one end is connected to ground. What is it that you want to accomplish with the equi=tech (as in what problem are you trying to solve)?

Edit - One other question, off topic from my above post. I have a little 120VAC to 9VDC transformer/rectifier in my amp for my SMPS standy circuit. The manufacturer of the amp recommends putting a metal oxide varistor on the "hot" side of the 120VAC feeding the transformer. Does anybody know what specs the varistor should be? I'm confused by what voltage and other ratings I should use. They also recommend a thermistor, i'm confused about what ratings that should be also.

Any varistor for 120 VAC use is OK, but make sure there is a fuse between the mains and the varistor - in the case of a really bad transient (such as a lightning strike) the varistor has a very limited capacity to absorb the transient, and you need the fuse as a secondary backup.

What is the thermistor supposed to do? Guard against transformer overheating?
 
So should the shield be hooked up to ground at both ends of the cord and just do not ground the amp chassis OR ground the amp chassis and cut the shield wire so it is not connected to anything on the amp side?

With regards to the varistor, I do have a 250V rated 0.5A glass fuse. I had done a bit of reading online about varistor selection and I read that a varistor 2 to 3x the operating voltage should be used otherwise it may open under small transients/spikes and need to be replaced. And no idea about the thermistor, there is nothing written about it, they just show on the wiring diagram that you should have a fuse followed by a thermistor and then a MOV.
 
So should the shield be hooked up to ground at both ends of the cord and just do not ground the amp chassis OR ground the amp chassis and cut the shield wire so it is not connected to anything on the amp side?

What would you ground the chassis to? Let the shield run to the connector on your amp, but don't connect that pin on the power input connector to anything. But this assumes normal power - do you have a specific reason to go for the "balanced power" (basically simulated ground plane) of the equi=tec? If so, that might change the situation (and advice).

With regards to the varistor, I do have a 250V rated 0.5A glass fuse. I had done a bit of reading online about varistor selection and I read that a varistor 2 to 3x the operating voltage should be used otherwise it may open under small transients/spikes and need to be replaced.

A varistor for 120 V transient protection will have a voltage high enough above 120V - and in any case, you do want the varistor to break down, not your transformer! A varistor is a sacrificial component, just as a fuse.

And no idea about the thermistor, there is nothing written about it, they just show on the wiring diagram that you should have a fuse followed by a thermistor and then a MOV.

Funny that they have no recommendation for the thermistor - but any normal PTC thermistor should do, as the current will be very low in your application. Just don't go for a NTC one...
 
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