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Hypex Ncore NC502MP - audible hum on one channel?

tiagobdonoso

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They just answered:
"
Hello,

I am not sure to well understand.
Amplififier can make a noise from the inside due to AC EMI FILTER 50 or 60hz.
This noise is not present to the speakers output.

Is it this problem or an other one ?
Is it possible to record the problem in video mode ?
use the email [email protected]

Best regards"
 
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No hiss or hum. Silent experience here NC252MP with ghentaudio kit. XLR.

I see that the OP’s amp has both RCA and XLR inputs. When I was researching Hypex amps I remember reading that this configuration was more susceptible to ground loops and it was best to have XLR inputs only and use an RCA to XLR cable. Has anyone else heard this?

Michael

If seen similar post from people around the web. Other things that get touched on with the HypeX is grounding issues with cases.
 

patoulol

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I had missed this thread.
I also had terrible mass loops with a "purifi" from Audiophonics. I could hear the hard drives of my PC in the speakers when the purifier was on. So I changed the electrical network to the pc and it was settled BUT by turning on the video projector the ground loop came back.

So I returned the purifi.
 

Gyroscopics

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BUT by turning on the video projector the ground loop came back.

I once had hum/buzz issue on my power-amp equipped HT system. I was able to localize the issue and found the root cause to be the coax cable feeding my set-up box which then pass the noise via HDMI into my receiver then into my amps. I fixed that issue by introducing a hum-eliminator coupler between the coax-cable and my Panamax power conditioner. That product is no longer available at Amazon but here is a similar product.

https://www.amazon.com/Ground-Loop-...coupler+hum+eliminator&qid=1623696883&sr=8-27
 

patoulol

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thanks for the tip for the moment I no longer have an external power amplifier. So no more problem. But if it comes back, I would think about testing this
 

Dlomb11

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Any news about this issue?
I would like to buy an Audiophonics NC502MP for my second system, but this issue discourages me ...
 
OP
M

MoreCowBell

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@Dlomb11 audiophonics doesn’t view the buzzing as a defect because the sound to them was only audible when ear was against the tweeter (It was loud to me at six inches and was still noticeable at 2ft) and was heard on all of their nc502 inventory. Doesn’t make sense to me but they provided a refund as it was returned within the return window.

I subsequently purchased a p502 from March audio and have been using it for about two weeks. There is very slight noise coming from left speaker but I can only hear it if I put my ear right next to the tweeter - accordingly this noise doesn’t bother me. The p502 sounds great, has a much smaller footprint than the audiophonics amp, and the 12v trigger actually works with my minidsp shd. Very happy with my purchase.
 

Dlomb11

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@Dlomb11 audiophonics doesn’t view the buzzing as a defect because the sound to them was only audible when ear was against the tweeter (It was loud to me at six inches and was still noticeable at 2ft) and was heard on all of their nc502 inventory. Doesn’t make sense to me but they provided a refund as it was returned within the return window.

I subsequently purchased a p502 from March audio and have been using it for about two weeks. There is very slight noise coming from left speaker but I can only hear it if I put my ear right next to the tweeter - accordingly this noise doesn’t bother me. The p502 sounds great, has a much smaller footprint than the audiophonics amp, and the 12v trigger actually works with my minidsp shd. Very happy with my purchase.

Ok thank you for the information.

I think I'll choose Apollon or Rouge Audio being in Italy ...
 

Call me Ali

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I once had hum/buzz issue on my power-amp equipped HT system. I was able to localize the issue and found the root cause to be the coax cable feeding my set-up box which then pass the noise via HDMI into my receiver then into my amps. I fixed that issue by introducing a hum-eliminator coupler between the coax-cable and my Panamax power conditioner. That product is no longer available at Amazon but here is a similar product.

https://www.amazon.com/Ground-Loop-...coupler+hum+eliminator&qid=1623696883&sr=8-27

Shouldn't the Panamax power conditioner take care of issues like this?
 

Audiophonics

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Hello,

Sorry for late reply.
Just to clarify the situation on the Hypex NC502MP module.
Yes, there is a channel with more noise than the other one. But It's really really low, not noticeable under normal use.
On 92dB speakers we can't hear it at more than 0.5 meter, with ear in axis with tweeter.

It seem to come from the module itself, as we tested it switching input cables, without input adapter board, without chassis. The bare module on a desk is having same behavior.
But I insist it should not be noticed unless you direct connect a very high sensitivity driver with at a low listening distance.

We made 2 measures at -10dbu and -100dbu input (5W and 0W output) on the LPA-S500 amplifier.
There are made with Averlab device so maybe not as accurate than Amir, but it give an idea.
 

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oupee

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Buy monoblocks. You can place them as close to the speakers as possible, and a 2 meter XLR cable is better than a 2 meter speaker cable.
 

Klint

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Hello,

Sorry for late reply.
Just to clarify the situation on the Hypex NC502MP module.
Yes, there is a channel with more noise than the other one. But It's really really low, not noticeable under normal use.
On 92dB speakers we can't hear it at more than 0.5 meter, with ear in axis with tweeter.

It seem to come from the module itself, as we tested it switching input cables, without input adapter board, without chassis. The bare module on a desk is having same behavior.
But I insist it should not be noticed unless you direct connect a very high sensitivity driver with at a low listening distance.

We made 2 measures at -10dbu and -100dbu input (5W and 0W output) on the LPA-S500 amplifier.
There are made with Averlab device so maybe not as accurate than Amir, but it give an idea.
I have 95dB speakers, should i look elsewhere then? other amplifier, Hypex, Purify.
Thanks
 
Last edited:

pma

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Just to clarify the situation on the Hypex NC502MP module.
Yes, there is a channel with more noise than the other one. But It's really really low, not noticeable under normal use.
Interesting, I have not a trace of audible noise/hum/buzz with my implementation of Hypex NC252MP module
and both channels behave the same. Do you think there is a difference from NC502MP? I think that Audiophonics works with NC252MP as well, what is your experience in this point?
 
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