Thanks for the reply, I fine the idea of Class D amps to be in line more with what I really want to do with my audio setup. However I have never heard them myself.
My attitude is kind of one where if I want to try and get a "tube" sound I will use a tube preamp with SS amps that way I have less peices of hardware in the system affecting the "synergy"
I also like that I can do some Monoblocks of these Ncore for a pretty nice price.
Wyred4Sound and DSonic amps look interesting as well but I like building electronics...
Fan-cooled RE2507-NC enclosure for dual NC400
Here is a sound recording I made so you can decide yourself: noctua_fan.mp3
Keep in mind that the fan is a Noctua NF-S12A FLX running at 6V DC instead of its normal 12V rating which reduces speed and noise.
I can't hear it at all until I am within 6 feet. At that distance, the only sound is that of the air and it's very subdued. Hearing it is only possible if there are no other sounds in the room. When my central air conditioning system is pushing air into the room through the air ducts, I can't hear the fan until I am within 1 foot. Playing music at very low volumes completely overrides the fan at 6 feet. If you look at my photograph, you'll notice the placement of the amplifier is conducive to eliminating fan sound. I could put sound-absorbing carpeting directly above the amp if I wanted to but I'd be wasting my time since I can't hear the fan at ALL from normal listening distances.
Here is a sound recording I made so you can decide yourself: noctua_fan.mp3
Keep in mind that the fan is a Noctua NF-S12A FLX running at 6V DC instead of its normal 12V rating which reduces speed and noise.
with the help of a bros locally, run some test with the mono into 8 ohms fixed resister.
48Khz rate Freq Respond.
48Khz rate THD.
96Khz rate Freq Respond.
96Khz rate THD.
48Khz rate Freq Respond.
An externally hosted image should be here but it was not working when we last tested it.
48Khz rate THD.
An externally hosted image should be here but it was not working when we last tested it.
96Khz rate Freq Respond.
An externally hosted image should be here but it was not working when we last tested it.
96Khz rate THD.
An externally hosted image should be here but it was not working when we last tested it.
Not quite sure what we are seeing here. So what gear did you actually measure, and how?
Hi everyone,
I'm person who help tane0019 with his NCore measurements. I will try to help him answer some of the questions here. 🙂
The equipment I used is a simple measurement jig, a modded EMU 0404 USB and ARTA measurement software.
I used ARTA's guide to build a measurement jig as below
My jig have a toggle switch to choose between 4ohms or 8ohms, and I simply adjust the gain to get an output of 2.83Vrms across the 8ohms. Then I ran impulse measurement and Step response of 1/12octave.
Do you mean the PSU for the amp? I believe tane0019 is using the PSU from Hypex.
I'm person who help tane0019 with his NCore measurements. I will try to help him answer some of the questions here. 🙂
The equipment I used is a simple measurement jig, a modded EMU 0404 USB and ARTA measurement software.
I used ARTA's guide to build a measurement jig as below
An externally hosted image should be here but it was not working when we last tested it.
My jig have a toggle switch to choose between 4ohms or 8ohms, and I simply adjust the gain to get an output of 2.83Vrms across the 8ohms. Then I ran impulse measurement and Step response of 1/12octave.
Do you mean the PSU for the amp? I believe tane0019 is using the PSU from Hypex.
Hi, and thanks for the very informative message!
Looking at the specifications of the EMU 0404, it seems that the THD is in the ballpark of what you measured, so it is hard to say if the harmonic distortion comes from the nc400 or from the EMU 0404. While the frequency response looks great, it might have been useful to have a picture showing more amplitude resolution (maybe restricting the frequency range to 20 hz at the lower end, but maybe going to 40KHz on the 96 kHz sample rate plot, and showing just the -40 to -30 dB range zoomed out to full scale).
I would love to see the same plots for the EMU 0404 look like with just a straight wire instead of the nc400.
you can read about EMU 0404 USB in diyaudio, its a very popular DAC/ADC
or you can refer to here
EMU input
E-MU 0404 distortion levels | Crazy Audio
and also modding EMU 0404
Below are the ultra sonic response using 96khz with the graph expanded to 40khz
Zooming in:
Last edited:
Thanks - I am familiar with the EMU 0404, it has impressive specs - but so does the nc400. The distortion of the 0404 might still be what dominates in your measurement.
I still only see them going to 20 kHz.
Agreed - calibrate the measurement system relative to the device under test
Nc400 is DC coupled iirc
That's what used to think also, but if you compare the distortion on the emu raising after 1khz, theoretically the NCore should also reflect the same behaviour if the source's distortion is a component of the amp output.
From what I understand, distortion from source should not be representative component of amplifier's output but not for opamps
Its already been calibrated via loopback, but that is for measuring actual output dB or voltage input.
You can refer to this EMU input
Isn't that very easy to check? Just compare the "R" and "L" input channels, as you already have the input signal going to the "R" input through a straight wire.
Ah, so the LF drop is due to the capacitor at the input - your measurement circuit is not DC coupled.
Or you referring to swapping the R with the L?
Otherwise in the setup, R is a reference voltage in a dual channel mode. If I switch to single channel mode, R will not be used.
Right, that's what I am saying - wouldn't it make sense to show both channels, so it is possible to compare the signal that goes through the nc400 with the one that doesn't?
Does "dual channel" mean you show the difference between the input and output signal?
- Status
- Not open for further replies.