Hypex Ncore NC502MP - audible hum on one channel?

[tiagobdonoso]

Another idea: try running the amp in 220V (phase + phase) and see if it solves the issue.

Interesting! I'll try that and will post here later.

 

[tiagobdonoso]

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"

 

[Freckles.Mcgee]

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]

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]

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]

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

 

[Davide]

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

 

[MoreCowBell]

@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.

 

[Davide]

@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]

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?

 

[Gyroscopics]

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

No. My Panamax did not take care of the issue.

 

[Audiophonics]

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.

 

[oupee]

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]

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

 

[pma]

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

PMA-NC252MP power amplifier

PMA-NC252MP As a manufacturer of electronic equipment I have been granted a web account for Hypex OEM web shop. My newly designed power amplifier based on excellent Hypex NCore modules is PMA-NC252MP. It is an amplifier with rated power 2x250W/4ohm and based on the NC252MP OEM modules. Hypex...

www.audiosciencereview.com

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?

 

[yllanos]

Anything new? I'm considering Audiophonics LPA-S500NC amp for my next upgrade

 

[tiagobdonoso]

Anything new? I'm considering Audiophonics LPA-S500NC amp for my next upgrade

I realized it was a problem with my turntable, at least I guess it was. I grounded it correctly (I was using the built in preamp) to the phono preamp and it stopped.
I don't have any problems anymore with the Audiophonics Hypex NC252MP. No hiss or hum at all.

 

[yllanos]

Well, I pulled the trigger. Now it's the waiting game until my order goes through the import process to my country

 

[yllanos]

Well, I got the amp now:

It arrived a few days ago to my country, but it took longer than usual on customs process.

Initial impressions are very good. I've only tested it for 30 minutes or so and I already feel the difference compared to my previous equipment. Seems to be a nice match to my speakers.

Build quality seems to be great, no complaints here. All connectors feel solid. However, I don't get why they included two feet on the back and just one on the front. I hope this doesn't create any instability. On the box they include some rubber feet, which I installed immediately since I needed it on my wood furniture.

I'm running a temporary setup while I await for a new DAC and a streamer. As of right now I'm using a PC with Qobuz/Tidal, a Topping EX5 as DAC + preamp, the Hypex amp, Magnepan MMG as speakers and a Rythmik F12 as subwoofer.

Anyway, I get no hum, hiss or any other noise coming from the speakers. The unit itself makes no noises either. I live in tropical humid and very warm weather all year long and the amp barely got warm during my initial test. I still have to take volume levels a little up, since I only went 52/100 as max volume (for now).

 

[mdunjic]

Long time lurker, first time post.

Is it normal to hear an audible hum (only from the right speaker) from the Hypex Ncore NC502MP modules?

I recently purchased a Audiophonics LPA-S500NC, a French made stereo amplifier that utilizes the Hypex Ncore NC502MP module.

My set up is as follows: new MiniDSP SHD --> Audiophonics LPA-S500NC amplifier (via XLR cables) -->pair of new Kef R3 (via Amazon basic 16gauge speaker wire/monoprice banana plugs).

I set everything up and I immediately noticed an audible hum coming only from the right speaker - it sounds like a ground loop. The left speaker has no hum noise. The noise through right speaker is noticeable at 6 inches but barely there at a foot away. Noise disappears from right speaker when I unplug the XLR cable from the amplifier (i tried various xlr cables and different outputs on the SHD but the noise was still there in right speaker only).

The amplifier was returned to Audiophonics. They tested my amplifier and also noticed a low hum in right speaker but said they could only hear it if their ears were right next to the speaker. They also state that this hum is present in ALL of their LPA-S500NC currently in stock. According to Audiophonics this is NOT a defect in the product because 1) i should expect noise in a 500 watt amplifier; 2) the hum is only apparent when they put their ear right next to the speaker.

Perhaps the noise floor is lower in my home compared to their office but how is this not a defect in their amplifiers when there is noise coming from only the right channel on ALL of their amplifiers but not the left??

Is this hum noise on the right channel limited to just Audiophoincs amplifiers or is it present on all Hypex Ncore NC502MP modules? (e.g. March Audio, Apollon audio, etc)

Am i crazy to expect no hum noise on these newish Hypex Ncore amplifiers? I feel like I am being gaslit lol.

Any input would be greatly appreciated!! Thanks.

I have Audiophonics LPA-S500NC (https://www.audiophonics.fr/en/powe...tereo-class-d-ncore-2x500w-4-ohm-p-15016.html), in my bi-amped setup, and can’t hear any hum in any of the channels … my speakers are Neat Motive 1 ... I believe their sensitivity is about 87 dBm … all connections are XLR