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Hypex NCore NC500 build

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I approve of this porn.

Now I use a mix of Supra LoRad and Eupen cables with knockoff Oyade plugs (chosen only for the ease of use wrt other types of plugs). I use Eupen cables without ground (only shield connected at schuss side) for DAC and passive preamp, with the power amps connected with Supra LoRad (ground connected). The power distributor is connected to the wall outlet with Supra LoRad as well.
 
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Apollon Audio and Rouge Audio Design sell the IcePower 1200AS2 with cheap chinese RF/EMI filter.

You can go to the Apollon site and there is a little chat widget. I asked for confirmation that they were not using RF/EMI filters on the AS1200 amp. I paste here their reply verbatim

We don’t use any EMI filters in our amplifiers. EMI filters are not the best choice for SMPS power supplies.
For our Icepower models, we don’t even use an additional fuse. We use a Furutech mains input socket connected direct to the modules.

Roberto
 
Additional filters with SMPS...

Mr. Putzeys specifically recommends not adding additional RF/EMI filters to the AC input of Hypex SMPS. The reason for this should be pretty clear to anyone with an understanding of these filters.
The SMPS already incorporate powerful filters at their input, usually C-L-C; as these filters are tuned, it could create problems if one adds another filter with additional capacitance, unless an additional filter is carefully tuned to work in harmony with the existing filter, one could very easily create a resonant circuit which creates more noise.
Unless one knows exactly what they are doing, and is willing to do some careful measurements of the results with a good scope, adding any additional filtering to the AC input of SPMS is a mistake, and it does not matter of you use cheap Chinese ones or more costly Schaffner products.

One should never just stack additional amounts of parallel capacitance to a circuit without understanding the potential for problems and being able to confirm the results by measuring.
 
At the end is the usual: trial and error.

In the chain:

* Yamaha system: one Schaffner + one RF Würth ferrite. Other Schaffner or RF ferrite -> worse sound.

* Marantz system: two Schaffner + one RF Würth ferrite. Other Schaffner or RF ferrite -> worse sound.

My computer, with silent PSU and low ripple at 5V (USB), is connected at Marantz chain, with my DCB + DCBx4 in the middle. And DIY Schaffner cable to the PSU.


The SMPS computer has, in the chain: two Schaffner + one RF ferrite


And the monitor chain (without any DCB): one Schaffner.


Trial and error.

DCB = DC Blocker.
 
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Mr. Putzeys specifically recommends not adding additional RF/EMI filters to the AC input of Hypex SMPS.

Hi Barrows,
but "support" at Hypex told me that the input socket that I have, a Schürter with integrated (tiny) mains filter does nothing to their PSU, no need to remove it. But yes in that very case there are several dozen of centimeters of wires between the mains socket and the UCD's SMPS400 filtered input, so maybe that's the OK case.
 
I

The real issue with pi or T filters is that they form a noise path between mains and chassis earth.

Have never been a fan of "Y" type caps and filters to G. Only parallel L-N capacitive filtering. Julf, you would not be concerned about the potential for creating a resonant circuit adding additional parallel capacitance to the AC input of a SMPS?

Agree that if you have enough wiring between the (added) filter and the SMPS there may be enough damping in the wiring to avoid problems, but I would still want to verify this by measurement.
 
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Have never been a fan of "Y" type caps and filters to G. Only parallel L-N capacitive filtering. Julf, you would not be concerned about the potential for creating a resonant circuit adding additional parallel capacitance to the AC input of a SMPS?

Agree that if you have enough wiring between the (added) filter and the SMPS there may be enough damping in the wiring to avoid problems, but I would still want to verify this by measurement.

For instance, I have 2.5 m of supra lorad between the filter and the amps...
 
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Hi,
I have just received my NC800SL from Apollon. It sounds great. I just wonder how long would it take to completely burn in to it's best performance? I only listen 1-2hrs a day at most. Is there anyway to speed up the burn in time ?
Thanks.

I used two resistors (8.4 Ohm / 50 W) with short cables and cheap bananas to build the things you can see in this album and you can leave them overnight with relatively high volume (check that the resistors stay under 70 degree celsius / 160 Fahrenheit). They need about 300 hours to fully burn in, but after 100 hours you will already notice 90% of the improvement, and very few 20-30 hours will already give you a clear picture of their character. But the how much the sound can become polished with time is almost eerily unnatural - in its naturalness.

Roberto
 
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I used two resistors (8.4 Ohm / 50 W) with short cables and cheap bananas to build the things you can see in this album and you can leave them overnight with relatively high volume (check that the resistors stay under 70 degree celsius / 160 Fahrenheit). They need about 300 hours to fully burn in, but after 100 hours you will already notice 90% of the improvement, and very few 20-30 hours will already give you a clear picture of their character. But the how much the sound can become polished with time is almost eerily unnatural - in its naturalness.

Roberto
Thanks for your advice !
 
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And what do you think actually changes physically with the "burn in"?

This is a very good question.

One thing that is scientifically known to change with activity is a capacitor. Capacitor forming has even been measured and there is a huge filtering difference between new and after several days of continuous operation. I suppose class D amps are more sensitive to this than traditional amps because they have smaller capacitors.

I doubt resistances and inductances have a similar burn in (or break in).

As for the MOSFETs, I have no idea. They have some intrinsic capacitance and I have no idea whether this has burn in too.

I doubt however that it is just my ears adjusting. The first hours are really a bit change. Then it is diminishing returns. And I have other references to compare to, so I can hear a different difference. For instance, initially the Apollons where a bit harsh - but they mellowed, and I could hear that the difference wrt to my headphone/headamp reference was closing.

It can still be, beyond some point, just an illusion/delusion, but if my brain tricks me to believe that some differences in, say, harshness wrt a constant baseline are vanishing, well, then I have no idea what I can trust.

Roberto
 
I agree because I have the same feeling, the first day I use and after a week, the sound is getting much better. Especially on voice and treble, while it's bass was already very good at my fist day.
I didn't play a lot everyday, just 1-2hrs, so I would say 10-20hr burn in time will have big difference.
I don't know the theory behind, but that's my observation.

Dick
 
One thing that is scientifically known to change with activity is a capacitor. Capacitor forming has even been measured and there is a huge filtering difference between new and after several days of continuous operation.

Capacitor forming is indeed a thing, but only for electrolytic capacitors, and the reforming time is usually hours, not days.

I suppose class D amps are more sensitive to this than traditional amps because they have smaller capacitors.

Smaller capacitors actually have less reforming issues.

I doubt resistances and inductances have a similar burn in (or break in).

Generally they don't.

As for the MOSFETs, I have no idea. They have some intrinsic capacitance and I have no idea whether this has burn in too.

No - the capacitor reforming issues only apply to electrolytics, not semiconductor capacitance.


It can still be, beyond some point, just an illusion/delusion, but if my brain tricks me to believe that some differences in, say, harshness wrt a constant baseline are vanishing, well, then I have no idea what I can trust.

"Laurel" or "Yanny"? :)
 
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