In my experience you can quietly hear a the coils whine when doing very high power testing, ie the actual audio signal (1kHz tone), but not in normal use. I have built a lot of the Hypex now and they are silent.
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Do NCore have buzzing noise?
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Aap op Sokken
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As mentioned, mechanical. Note that this is not only coil whine, caps can also buzz. In fact, the noise from my amp is likely the caps in the smps, since the coils are used at higher frequencies, but the noise sounds like harmonics of a 50 Hz signal.
It's not normal behaviour in my experience, and I have seen a lot of them
Aap op Sokken
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Thanks for the input. I didn't think it was a fault, because both monoblocks make the exact same noise. Also, all power supplies buzz if you listen close enough. TV's, phone chargers, PC's, etc. Some are just louder than others. Apparently, these are a bit louder than they should be. But I don't think I will do anything about it.
OP
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Yes. Full Digital Amplifiers like FX-Audio D802 or Alientek D8 can cause hiss in the twitters like some active speakers (JBL 305p MKII...) in my experience. But that's not what I wanted to talk about here.
Audioagnostic
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My Audiophonics MPA-S125NC with Hypex Ncore NC122MP makes a buzzing sound as well. It seems to get worse. The sound only disappears when I turn it off with the switch in the back. When switching it off in the front the sound remains.
It is not very loud but annoying nevertheless.
Is this a fault? Should I send it back? Still under warranty. What is the explanation of the sound only disappearing using the switch in the back?
Pointers, similar observations and potential cures are appreciated.
To be clear, no audible sound coming from the speakers with the amp idling, noise is coming from the case of the amp.
It is not very loud but annoying nevertheless.
Is this a fault? Should I send it back? Still under warranty. What is the explanation of the sound only disappearing using the switch in the back?
Pointers, similar observations and potential cures are appreciated.
To be clear, no audible sound coming from the speakers with the amp idling, noise is coming from the case of the amp.
I had the same with my nc400:
https://www.audiosciencereview.com/...-hypex-nc400-diy-amp.5907/page-40#post-246193
Audioagnostic
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Were you able to solve it? I did not go through the entire thread but it seemed there was a case resonance as well?
The case was not resonating but did increase the effect quite a bit.
I now solved it by placing the Amp behind the speaker in stead of on top of my subwoofer.
Thats enough to make inaudible to me
So not a real solution, but this als works for me
RandomEar
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The thread is older, but I thought I'd add one more data point: I also had problems with a buzzing noise from my NCore-driven Audiophonics MPA-S125NC, as described here. It was a combination of 550/650/700 Hz tones, audible from up to 2 m away in a quiet environment and roughly 0.5 m on an average day with some city noises around. Send it back, because this wasn't acceptable to me, as I have my amp close to my listening position.
tuskenraider
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Got my Audiophonics LPA-S500NC today. Relay clicks for on/off and it is silent at the unit at idle, and nothing noted during a listening session. I can hear the faintest hiss at the tweeter of my speakers with my ear about 3" away. Connecting a trigger cable to it from my Denon X4700(connected via RCA pre-outs) made my speakers hum like crazy. With my Yamaha RX-A3080, which has XLR's for the main pre-outs, it was silent, as with a test connected with RCA's as well.
It could be the cable. I tried my buckeye amp and vtv amp with the x4400h using s Monoprice rca to xlr, it was near silent.
Do the seperat hypex power modules which are used for the ncx500 (think smps1200a700) have the same behavoir? I mean the coil whine that you can hear with ear next to the device?
Have the same issue with a nc502mp unit. Hard to notice but once heared, i focus on it...
With the app "spectroid" i can measure it with my Phone 3cm to 10 cm away from the device but i think i can hear it 3 Meters away also. Its from 10khz to 20khz as you can see on attached screenshot
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In my experience - if the mains are very noisy there will be some audible noise from the coils in the mains input filter on the SMPS. I have heard this on both Hypex' and Icepower's SMPS. A couple of years ago I had mains power with more than 20% THD, and that created audible buzz. The speaker output was dead quiet though.
Thanks for your reply. Strange is that the amp buzzes also wehn powered Off. very annoying. Just when i flip the power switch on the back, it will dissapear after ~3 minutes.
Dont know If i should send it back and upgrade to a NCx500 would be a solution or not
Dont know If i should send it back and upgrade to a NCx500 would be a solution or not
Do you know if that switch physically disconnects the input power, or is it a "soft switch" that just disables the SMPS?
Then I guess the mains is disconnected. This buzzing must be caused by something else than mains noise.
The SMPS on my own Nilai amps blinks a white LED for few minutes after power is removed, but no buzzing noise.
The SMPS on my own Nilai amps blinks a white LED for few minutes after power is removed, but no buzzing noise.
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