Hypex Ncore

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Julf

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Joined 2011
markusA said:
The signal is currently floating and referenced to signal ground as per the power-amp.
Click to expand...

It can't be both "floating" and "referenced to signal ground" at the same time.

A differential input is just that - differential. So the signal is based on the difference between the inputs, and is *not* referenced to ground in any way.

If by "power-amp" you mean the nc400, it does not reference the inputs to ground.

Viewing the differential of hot and cold I get 3.3V at full swing I.e. 3.3V peak.
Click to expand...
No, that would be peak-to-peak, not peak.

(Hot +1.65V and cold -1.65V)
Click to expand...
Again, they are not referenced to some halfway point.
 
markusA

markusA

Member
Joined 2009
It might be that my terminology is totally off but regardless of that. Right now I have a transformer output. The transformer input sees a 1.65V bias to both hot and cold. When the hot peaks it'll hit 3.3V and at the same time the cold will be at 0V. On the transformer output the difference between hot and cold will be 3.3V.
(My old amps were single ended and I used a Xlr to RCA cable to take care of that. )
Is that considered 2.3Vrms or 1.15Vrms now that we're talking balanced connection?
 
J

Julf

Member
Joined 2011
markusA said:
It might be that my terminology is totally off but regardless of that. Right now I have a transformer output. The transformer input sees a 1.65V bias to both hot and cold. When the hot peaks it'll hit 3.3V and at the same time the cold will be at 0V. On the transformer output the difference between hot and cold will be 3.3V.
(My old amps were single ended and I used a Xlr to RCA cable to take care of that. )
Is that considered 2.3Vrms or 1.15Vrms now that we're talking balanced connection?
Click to expand...

The only thing that matters is "the difference between hot and cold will be 3.3V" part. That means that your signal is 3.3 V peak-to-peak, or 1.65 V peak, corresponding to 1.17 V rms for a sine wave.

I am not sure it is just a confusion of terminology - I am not sure you understand the fundamental principle of a differential input. The output of your transformer doesn't "know" one of the inputs is connected to ground - it just sees a voltage between the transformer output pins. Measuring just one of those pins against ground doesn't produce any meaningful result.
 
M

magicLX521

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Joined 2010
magicLX521.com
ncore subsonic observation

Just made an observation, while having ncores amplifying L channels woofer and another amp doing the amplification for the R woofer (no Crossovers between amps and drivers) The side with the ncore showed a much more pronounced membrane movement (membrane control?), when feeding with a 2Hz sine wave. I swapped amps and speakers to exclude gain/source imbalances. The side with ncore always stayed the one with the much more pronounced membrane movement. Does this ncore (much more dynamic) subsonic behaviour point towards a more dynamic behaviour in the audible range? Or is it rather a nonsense observation?
 
J

Julf

Member
Joined 2011
fbee said:
The side with the ncore showed a much more pronounced membrane movement (membrane control?), when feeding with a 2Hz sine wave.
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Careful - that sounds like a good way to destroy your woofer.

Yes, the ncore, being DC-coupled, can reproduce the 2 Hz, while most other amps probably won't - but the speaker might not be designed to take any significant energy that low in frequency.
 
B

barrows

Member
Joined 2010
fbee said:
Just made an observation, while having ncores amplifying L channels woofer and another amp doing the amplification for the R woofer (no Crossovers between amps and drivers) The side with the ncore showed a much more pronounced membrane movement (membrane control?), when feeding with a 2Hz sine wave. I swapped amps and speakers to exclude gain/source imbalances. The side with ncore always stayed the one with the much more pronounced membrane movement. Does this ncore (much more dynamic) subsonic behaviour point towards a more dynamic behaviour in the audible range? Or is it rather a nonsense observation?
Click to expand...


Does the other amp have capacitor coupling at its input for DC protection? If so, it may be attenuating signals as low as 2 Hz.
 
N

NikolaVeber

Member
Joined 2013
Hi everyone,

I did my best going trough the thread looking for a definitive nCore/Power Supply configuration "guide".

So far, I have found this:
Bruno Putzeys said:
The SMPS400 is indeed a competent substitute for the SMPS600 if you're not planning to drive heavy loads and if you don't mind the extra idle losses. One tweaky detail is the use of chokes (on the 600) instead of ferrite beads which yields a small but measurable improvement of the distortion spectrum (high order harmonics are reduced from below -120dB to unmeasurable). The methods used to reduce CM noise on the SMPS400 and 600 are also different but they are equally good.
Click to expand...

And various posts stating that one could use one SMPS600 to power two nc400's, if your listening levels/speakers don't require ncore to work very hard.

I intend to use them with OBL-11's (OBL11) - min 4Ohm, ca. 95 db sensitivity. I assume they wouldn't be too hard to drive.

So, as I have to mind my budget, the question:
Using SMPS400 seems to have slight negative impact in sonic performance.
Does a configuration using single SMPS600 to drive two nCores have any negative impact on sonic performance on moderate load (listening levels)?

Has anyone done any tests, driving 1/2 nCores with a single SMPS600?


Any insight is much appreciated!


Cheers
Nikola


Edit:
I found this as well:
Julf said:
Really?

As long as the amplifiers are not so close to their maximum output that they are clipping, the output will be independent of the power supply voltage (the supply ripple rejection of the nc400 is specified as at least 75 dB, the "near-static" power supply voltage variation rejection is probably much higher still.

75 dB means a 10% in the supply voltage will cause an output variation of 0.002% of full scale...
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Esperado said:
That is just what i hear.
Notice it is very subtle, and can vary, depending of your enclosures ability to present a precise space localization.
Mine are so, with a very high efficiency speaker (compression driver and spherical horn based), supposed to be less power asking than others, so, less sensible to those effects.

Just my personal experience with careful listening comparisons and a full professional life dedicated to music (audio design and music producing).
As it is subjective, i will not fight against any opposite argues.
The last experience is recent, while i work on my system, to move from mono amplification with passive filters, to active filtering. I tried separated PSU, then unique one. Same conclusion.
I can be biased with my own believes too, but i do not think so.
There is a negative aspect: you need care with grounding implementation.
Click to expand...
 
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B

barrows

Member
Joined 2010
Need help with transformer coupling...

Hi Ncore folks. I am interetsed in transformer coupling the input of my Ncore 400 stereo amp. Please do not try and talk me out of it, or ask why, I am just looking for some help in configuring it. I have chosen the Lundahl 1588:

http://www.lundahl.se/pdf/1588.pdf

My build is XLR input only, and the source is fully balanced, so this will be a balanced to balanced input, 1:1. I want to achieve total isolation, including ground. XLR pin 1 (shield) is connected to chassis, and I assume that the 1588 pin 8 (shield) should also be connected to chassis. I have the choice of either the serial or parallel connection scheme for pins 2 and 3, anyone who understands transformer coupling able to help with what the difference is between these two schemes?
Also, I assume that nAmpon will still go to chassis, but what about the ground of the NC-400 input cable? I want to keep it isolated, should it connect to the centertap as shown in the serial connection scheme?
Thanks for any help.
 
J

Juhleren

Member
Joined 2011
NikolaVeber said:
Hi everyone,

I did my best going trough the thread looking for a definitive nCore/Power Supply configuration "guide".

So far, I have found this:


And various posts stating that one could use one SMPS600 to power two nc400's, if your listening levels/speakers don't require ncore to work very hard.

I intend to use them with OBL-11's (OBL11) - min 4Ohm, ca. 95 db sensitivity. I assume they wouldn't be too hard to drive.

So, as I have to mind my budget, the question:
Using SMPS400 seems to have slight negative impact in sonic performance.
Does a configuration using single SMPS600 to drive two nCores have any negative impact on sonic performance on moderate load (listening levels)?

Has anyone done any tests, driving 1/2 nCores with a single SMPS600?


Any insight is much appreciated!


Cheers
Nikola


Edit:
I found this as well:
Click to expand...

Hi Nikola,

I'm not sure that anybody has actually listened to Ncore/SMPS600 vs Ncore/SMPS400. The way I understood Bruno's point was that running two Ncore's on one SMPS400 would restrict power compared to SMPS600. However, if you go with one SMPS400 per Ncore module (still cheaper than one shared SMPS600), I would think that you should get at least comparable power AND better channel separation. All of this is of course a bit theoretical unless someone actually did the comparison :)

Best,
 
Omholt

Omholt

Member
Joined 2009
lydogakustikk.no
Ncore might have a contender in town very soon. Anaview is releasing some new class D modules. First one is only with 25w in 8 ohm (50W in 4 ohm) but more powerful amps will come later. PSU is on board.

Someone said measurements are said to be better then Ncore. Anaview uses something called AMS-servo, so in other words not much use of feedback.

I've personaly only seen Gain and phase vs frequency and THD vs power measurements.
Here's one preliminary of many:
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