Problem with Hypex Ncore(solved)
Last month i have bought 2 Ncore400 modules but after installing them there was a high pitch noise in the output. My supplier send me two new ncore's and they have the same problem. These are R5 pcb's from the latest batch. Are there more people who have the same problems? May be do i have another problem.
Last month i have bought 2 Ncore400 modules but after installing them there was a high pitch noise in the output. My supplier send me two new ncore's and they have the same problem. These are R5 pcb's from the latest batch. Are there more people who have the same problems? May be do i have another problem.
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Have you had earlier nc400's in the same configuration without noise? Have you followed the guidelines about twisted wires and avoiding loops in the output cables? What is your ground/earth scheme?
yesterday i treid a linear power supply and the noise was gone. So the smps generate interference with the ncore. But the smps function good with normal UCD400.
Exactly the same circuit layout?
When you say "linear" power supply, I assume it is an unregulated supply (just a transformer, rectifier bridge and filter capacitors)?
You haven't answered my questions about twisted wires, output cable routing and ground/earth scheme.
Which SMPS are you using? In my experience the SMPS600 is extremely quiet.
When you say "linear" power supply, I assume it is an unregulated supply (just a transformer, rectifier bridge and filter capacitors)?
You haven't answered my questions about twisted wires, output cable routing and ground/earth scheme.
Which SMPS are you using? In my experience the SMPS600 is extremely quiet.
Yes, the linear supply is a unregulated supply.
I use smps400a400 the 600 is to expensive and i have already build 2 ncore amps with same configuration and connections. Tomorrow i will try to place one of the latest ncores in an other amp.
I use smps400a400 the 600 is to expensive and i have already build 2 ncore amps with same configuration and connections. Tomorrow i will try to place one of the latest ncores in an other amp.
Ya, what SMPS?
And what linear? Wouldn't you need either two transformers or a regulator? 60 +/- and +12v?
I've been thinking about powering an NC400 with a linear for awhile. Everyone talks about how "amazing and high-tech" the SMPS is but... I've been into the sound of linear with class D.
Sure it's not just a bad solder joint on one particular SMPS board?
And what linear? Wouldn't you need either two transformers or a regulator? 60 +/- and +12v?
I've been thinking about powering an NC400 with a linear for awhile. Everyone talks about how "amazing and high-tech" the SMPS is but... I've been into the sound of linear with class D.
Sure it's not just a bad solder joint on one particular SMPS board?
Compared to any constant current power supply that bleeds off 200-godknowswhat watts of energy every moment of it's life??? NO.
Wikipedia
Linear:
"If regulated: efficiency largely depends on voltage difference between input and output; output voltage is regulated by dissipating excess power as heat resulting in a typical efficiency of 30–40%.[15] If unregulated, transformer iron and copper losses may be the only significant sources of inefficiency."
SMPS:
"Output is regulated using duty cycle control; the transistors are switched fully on or fully off, so very little resistive losses between input and the load. The only heat generated is in the non-ideal aspects of the components and quiescent current in the control circuitry."
However lots of SMPS's produce significantly more heat than unregulated linear (varies greatly with SMPS). I was thinking non-regulated. I think their estimates on regulation is for something shitty, btw.
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Koi,
Maybe it is wise to use the advised power supply recommended by Hypex.
Or is this a Hypex bashing thread after you left a Dutch diyaudio forum doing the same?
Maybe it is wise to use the advised power supply recommended by Hypex.
Or is this a Hypex bashing thread after you left a Dutch diyaudio forum doing the same?
Here's another comparison.
With good quality audio gear you probably see closer to the 20% efficiency difference.
Think about this... What's 60% + 85% efficient? (L D)
What's 80% + 85% efficient? (S D)
Now what's 50% + 10-30% efficient? (LR A)
With good quality audio gear you probably see closer to the 20% efficiency difference.
Think about this... What's 60% + 85% efficient? (L D)
What's 80% + 85% efficient? (S D)
Now what's 50% + 10-30% efficient? (LR A)
I wasn't so much thinking about efficiency (unregulated is pretty efficient), but size, stability and sustained current capability.
I'd also recommend using the by hypex designed power supply. If the NCore is not to your liking then it is probably a better idea to use another amp instead of trying to build a custom power supply.
I did find a similar thing about my NCores though, an annoying high pitch sound / brightness in the background that was always present. I didn't find anything when I measured but I could spot the NCore in a blind test due to this brightness. It was the main reason I dropped my NCores for the midrange and upwards and went back to inefficient but nice sounding class A amps. The UcD / NCores shine in the bass though so I kept the UcDs there.
I did find a similar thing about my NCores though, an annoying high pitch sound / brightness in the background that was always present. I didn't find anything when I measured but I could spot the NCore in a blind test due to this brightness. It was the main reason I dropped my NCores for the midrange and upwards and went back to inefficient but nice sounding class A amps. The UcD / NCores shine in the bass though so I kept the UcDs there.
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Perhaps the Ncores have a resonance problem. It wouldn't be a surprise. SMPS's aren't the best for dealing with such things, in my experience.
Koi,
Maybe it is wise to use the advised power supply recommended by Hypex.
Or is this a Hypex bashing thread after you left a Dutch diyaudio forum doing the same?
Well, I can imagine that people will get angry and frustrated if the only way is to use one specific power supply.
In my experience Hypex does have more problems with pitching noise.
Especially with multi amplifier modules at one power supply.
I even had a similar problem with a linear power supply.
One of the solutions could be to use a slightly bigger cap from the RC low pass network at the input of the amplifier.
Normally it's around 100pF or so, and changing it to 10nF solved the problem for me
Don't know if that also would work in your case. It's a bit difficult to judge on such a distance.
I have not have had any problems with my nc400's sharing one smps600 for 2 amps, and having multiple amps in the same enclosure. It does seem that the nc400 is sensitive to proper wiring, and the guidelines from Hypex and Bruno need to be followed.
I don't have a schematic.
Most SMPS's seem to offer filtration to keep noise from coming in, but don't often have a low inductance path out. As much resonation is possible, so is noise. They may have low resistance so decoupling caps work. AC filtration and/or low inductance path is better than DC filtration.
Dampening can be done in a lot of ways though, depending on where and what. If you don't have a decent return path however the impedance may fight you on say using a resistor effectively at a good value.
I wish I had a better explanation for why the DC environment isn't nearly as good of a place to filter.
This guy has been changing output cap filters with some great feedback. EVS Homepage
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