[Rclark]

not a chance. You're hearing some sort of noise in your system, but it's not the amps.

[barrows]

You are the first person to report this. RClark is right, the noise floor is 130db down. I would look for other explanations.

Hilarious!  Respectfully, what "other explanations" would you suggest, considering we are talking about only an amplifier connected directly to a loudspeaker, with no other components connected?

[doug s.]

Hilarious!  Respectfully, what "other explanations" would you suggest, considering we are talking about only an amplifier connected directly to a loudspeaker, with no other components connected?

this should be good - anxiously awaiting the fanboy response...   

doug s.

[roscoeiii]

Lemme get this straight, we are worrying about a noise floor only heard within 1 to 1/2" of the tweeter?

Hardly something I would lose any sleep over at all.

[cab]

Hilarious!  Respectfully, what "other explanations" would you suggest, considering we are talking about only an amplifier connected directly to a loudspeaker, with no other components connected?

grounding issues, rfi/emi, poor connections, problem with the dc offset in the amp or other internal problem, etc.

[Rclark]

 There are people with 105+db efficient systems that can't hear a thing. These don't have an audible noise floor. Kind of one of the major points of the amp. Something is faulty.

[roscoeiii]

But for noise at 1" from the tweeter? Worth bothering with? Not in my book.

[barrows]

There are people with 105+db efficient systems that can't hear a thing. These don't have an audible noise floor. Kind of one of the major points of the amp. Something is faulty.

Nothing faulty, I have had two pairs of nCore modules here, all (4) exhibit the same level of noise with nothing at their input.  I am not suggesting that the noise is a "problem" in any way, but I can hear it as described.  As mentioned, the noise floor in my room on a calm night is very low.  I live in a small home in a rural area, and as long as the furnace is not running, there are really no sources (beyond the noise of the earth itself) of background noise to contend with.

But this distraction has gotten us a little off topic.

[barrows]

grounding issues, rfi/emi, poor connections, problem with the dc offset in the amp or other internal problem, etc.

Nope: this is smooth, even, noise.  Completely unrelated to grounding issues, RFI, or a bad connection.  There are no bad connections, or DC offsets.  I have measured all nCore modules for offset and adjusted accordingly when necessary.  I am not exactly inexperienced in these areas…  Additionally, 4 different modules and SMPS600s have all exhibited the same noise level.  If it were dues to a "problem" I doubt that it would be this consistent.

But when I get the current build together I will check again with shorted inputs as well, as that will eliminate RF pickup through the input as a factor. 

[Rclark]

Gotta be something wrong. In your build, maybe your power. I've read of a person having this issue before, way deep in the diyaudio thread, and it was resolved, then he couldn't hear anything after that, not even ear pressed up.

[barrows]

Nope, nothing wrong.  As mentioned, all modules of four exhibit the same noise.  Either when tested without a case and wired simply to an XLR (shield and nAmpon to pin 1), or, when wired up in a case.  I have tested 4 modules separately, two of those both without any case, and then in monoblock cases wired per Hypex's recs. 
There really is nothing wrong here though, just the normal noise floor of the amps.  It is OK with me if others cannot hear it, their rooms are likely louder than mine. 

[Rclark]

I don't think so. Most of those guys are pretty hardcore, with treated/high end rooms and set ups. There is no reason you should be hearing an amp with an S/N ratio, and measured, of 130dB.

[doug s.]

Gotta be something wrong. In your build, maybe your power. I've read of a person having this issue before, way deep in the diyaudio thread, and it was resolved, then he couldn't hear anything after that, not even ear pressed up.

I don't think so. Most of those guys are pretty hardcore, with treated/high end rooms and set ups. There is no reason you should be hearing an amp with an S/N ratio, and measured, of 130dB.

  doug s.

[Russell Dawkins]

Nothing faulty, I have had two pairs of nCore modules here, all (4) exhibit the same level of noise with nothing at their input.

Are you saying you hear the noise with no signal or with the inputs open, i.e., with nothing across them?

[barrows]

Are you saying you hear the noise with no signal or with the inputs open, i.e., with nothing across them?

Both/either…  Remember, this is very low level noise, ear within an inch or less (it is hard to measure that close, lol) of the tweeter.  Either with the DAC connected, or with the inputs open.
I am waiting for a chassis to arrive to do the current (stereo) build.  When that is done, I will test the same with shorted inputs as well, to avoid the possibility of noise (RF) pickup through the inputs.
 

[cab]

Any refrigerator compressors, light rheostats or the like pumping garbage into your mains?

[barrows]

Any refrigerator compressors, light rheostats or the like pumping garbage into your mains?

Nope, not during the test.  I am well aware of the potential effects of external noise sources.  My house is also on a dedicated transformer, not shared with any neighbors.

[Rclark]

Huh, weird, well I hope you get it sorted out. I can't hear a thing on either of my speakers, volume cranked, ear pressed to the panel, or tweeter, etc. I know you said you were going to explore the issue further, good luck with that.

And let us know how your grounding scheme works out, if there's any improvement.

[roscoeiii]

Huh, weird, well I hope you get it sorted out. I can't hear a thing on either of my speakers, volume cranked, ear pressed to the panel, or tweeter, etc. I know you said you were going to explore the issue further, good luck with that.

And let us know how your grounding scheme works out, if there's any improvement.

But is this really something that needs sorting out? Bigger problems out there in the audio world than something only audible 1" from the tweeter.

[Rclark]

It just doesn't make sense is all, doesn't jibe with my experience, or others. That's all. I know hearing a slight noise .5 inch from the tweeter in a silent room is not a big deal, but he shouldn't be hearing anything at all, the fact that he is tells me something is wrong.