[Julf]

Which way is J5 connected to the heat sink?

[turbogti]

I used a multi meter test the connection between (1)/m3  and J5, and they are connected, as in current can pass through.  hmm

[Julf]

Not sure it is a good idea to go around probing with a multimeter. So your measurements are with a nc400 that is not connected to anything in any way?

[turbogti]

nothing. just the module itself.

[Julf]

I am a bit reluctant to check on one of my nc400's, as I have learned (the hard way) not to subject delicate electronics to the voltage of a multimeter on a resistance range. I know Bruno commented something on diyaudio about how the heat sink could be connected, but I can't find it right now...

[FloridaBear]

I can confirm that observation. I'm not sure why it was designed that way, however.

[LarsSt]

Hi,

Built my nCores a few days ago (nc400 V4). When done I did some resistance (Ohm) measurements.

Discovered that there was a connection between the negative speaker binding post and the chassis on both amplifiers. Disassembled both since I thought I had made some mistakes mounting the binding posts. When disconnecting the negative cable from the nc400 there was no connection between chassis and negative binding post.

Made similar measurements on my other (ShengYa A17CS) amplifier, no connection between chassis and binding posts.

A bit strange this me thinking.

[turbogti]

yes, that was exactly what happened to my set up too. I thought the bindings had contacts to the case.

nice built btw!

Hi,

Built my nCores a few days ago (nc400 V4). When done I did some resistance (Ohm) measurements.

Discovered that there was a connection between the negative speaker binding post and the chassis on both amplifiers. Disassembled both since I thought I had made some mistakes mounting the binding posts. When disconnecting the negative cable from the nc400 there was no connection between chassis and negative binding post.

Made similar measurements on my other (ShengYa A17CS) amplifier, no connection between chassis and binding posts.

A bit strange this me thinking.

[jugi6]

A tip to all you NC400 builders: place a shield between the power supply and the amp module. Really, it's a big difference(!) The sound is quite a bit more realistic, clear, less noise. Didn't think of it earlier, just though I'd make one like in the NC1200 demo amp of Hypex's. But once tested without, there is no question the shield has to stay.

I've wondered why people say that amps like Veritas and Atsah are said to sound better than the DIY stuff - even though Bruno states the NC400 to be at least equal to the NC1200. I think little tweaks like this make a big part of the difference. Proper power cord to the SMPS, short signal input cable, robust enough cable to the speaker terminals, shielding between power supply and amp - things that cost basically nothing but give great benefits. You should at least try. 

Btw. also tried a couple of different "better" inlets (Furutech, plain copper etc.). To me the basic 3€ inlet gives the most organic and relaxed sound. So everything "better" doesn't sound better. Of coarse things (system balance) may change when different upstream components are intoduct to the system - like Triode Wire Lab power cables. We'll see. 

- Jugi

[jugi6]

My take - although the input signal cable here is still long for testing purposes.

[Atlplasma]

A tip to all you NC400 builders: place shield between the power supply and the amp model. Really, it's a big difference(!) The sound is quite a bit more realistic, clear, less noise. Didn't think of it earlier, just though I'd make one like in the NC1200 demo am of Hypex's. But once tested without, there is on question the shield has to stay.

I've wondered why people say that amps like Veritas and Atsah are said to sound better than the DIY stuff - even though Bruno states the NC400 to be at least equal to the NC1200. I think little tweaks like this make a big part of the difference. Proper power cord to the SMPS, short signal input cable, robust enough cable to the speaker terminals, shielding between power supply and amp - things that cost basically nothing but give great benefits. You should at least try. 

Btw. also tried a couple of different "better" inlets (Furutech, plain copper etc.). To me the basic 3€ inlet gives the most organic and relaxed sound. So everything "better" doesn't sound better. Of coarse things (system balance) may change when different upstream components are intoduct to the system - like Triode Wire Lab power cables. We'll see. 

- Jugi

Is there a rule of thumb for how thick the shielding has to be? Are steel and aluminum equally effective?

[jugi6]

Is there a rule of thumb for how thick the shielding has to be? Are steel and aluminum equally effective?

Don't really know. Just tested it with the 5mm aluminium sheet I have.

- Jugi

[Regnad]

The Veritas has a thick aluminum slab between the modules.  It is not routed-out from the block so it also allows for a middle screw on the bottom-plate which makes the amp very solid.

I also find the Veritas to sound better than the NC400s.   Usual my system, my ears, etc.

[Julf]

less noise.

How many dB?

[Rclark]

 So that is the great NC1200 difference. Not sure what you mean by noise in a noiseless amp though. I'll go to Home Depot on my next day off and get some aluminum and a hack saw to see what's up here.


Hmmmmm. I could try with layers of foil right now..

....busy folding it to the right size...

.... I don't hear any difference whatsoever.. still the same gorgeous sound as before..

[jugi6]

Not sure what you mean by noise in a noiseless amp though.

Noise in a general sense. Not noise coming from the speakers when idle, but music coming from a blacker background. Or like another AudioCircle mate nicely put it: "A clearer sounding and more detailed presentation of the music".

- Jukka

[Julf]

Noise in a general sense. Not noise coming from the speakers when idle, but music coming from a blacker background.

Ah. To an engineer, "noise" actually implies something that can be measured.

[jugi6]

Well Julf, I think it's you making the biggest noise here - had a look at your other posts too...

You just have to poke at every comment that your "know everything, right about everything, prove me every thing" engineer self accentuating self-esteem can't quite grasp upon. You are over 50 years old. Why do you act like a teenager?

If you don't have anything constructive to say, why say anything at all? Let other people do as they like and practice this hobby as they wish - it's nothing away from you.

But as I'm afraid you just can't let go and change your behavior, I'm saying in advance that from now on I'm just going to ignore your posts.

- Jugi

[Julf]

Jugi,

Could we please focus on the issue at hand instead of resorting to personal attacks?

Audio electronics is a branch of electronics. Electronics is an applied science, as practised by engineers. Amplifiers and other pieces of electronics are developed by following sound engineering practices and the scientific method. An essential part of that method is isolating and verifying claims objectively - until you do that, you can not be sure the problem you are trying to solve even exists.

People have made claims about audible differences between the NC400 and the NC1200, as well as bridged and unbridged NC400's, different power supplies and various grounding/EMC protection/isolation practices. We are all interested in those differences. Why do you have an issue in trying to isolate and verify those claims beyond vague subjective descriptions of impressions under uncontrolled conditions? One would imagine we are all interested in finding out the real facts.

[turbogti]

Don't really know. Just tested it with the 5mm aluminium sheet I have.

- Jugi

try copper plates @  2.6mm (at least) thick, grounded. They work much better than Alu/SS.  Ideally CF is a much better material for EMI shielding but those specially made CF sheets are hard to access. They tend to be used on satellites, aircrafts or other military purpose.