hypex ncore

[robbbby]

Originally Posted by StigErik

My Ncores are dead quiet. Always. When I put my ear onto the cone of my 98 dB efficient woofers, I can't hear any noise at all. Any HF noise would get lost, as the response of the woofers drops off above 2kHz, but anyway .....

My mid and woofers are dead silent, just noise from the tweeter. Also I get popping when cycling the amps on/off without any input connected.


Julf, good idea, somebody else mentioned double checking all connections/grounding inside enclosures.

Right now I do not have earth/ground connected to the case, should I ground the case to earth?

[Theodosis O.]

Robbby, have you checked the DC at the output of ncores ?

[Julf]

Originally Posted by robbbby

Right now I do not have earth/ground connected to the case, should I ground the case to earth?

As in house/mains earth? No, I wouldn't, but I would make sure the case is connected to pin1 of your XLR connector (and pin 4 / ground on the nCore input plug - the shield on the input cable).

[jtwrace]

Mine are dead quiet too as they should be.

[ua100k]

Originally Posted by robbbby

Hey guys, trying to do some troubleshooting and had a question for those of you that own ncores. When powering cycling the amps without anything connected to the amp other then the speakers are you guys experiencing any light popping at power up and power down?
When the amp is powered up, speakers connected but no input, are you guys getting static/white noise when you put your ear near the tweeter?

I'm just trying to figure a few things out and some are saying they get dead silence at the tweeter with the amp on and no source and some are saying the static/white noise is normal. Just wanted to see what others with ncores are experiencing.

Thanks

You are getting the noise from the amp and/or power supply.
Check in this order.
1. Audio input wires are shielded and away from other noise sources on the boards.
2. Move your boards away from the inputs. You might have just the right amount of interaction. You can try shielding with foil.
3. Play with your grounding. You may have your circuits acting like a radio receiver. Try grounding the input XLR audio ground/Chassis pins. Try grounding the chassis to power supply ground, and so on.

[mr_push_pull]

this is interesting. my UCDs only output the slightest amount of noise that can only be heard ear against tweeter at max volume. and I'm not even sure its amp noise, it may be because of front end (DS1666 volume control). output wires running relatively close to input ones, not balanced, not shielded, not twisted. true, speakers are only 83 dB W/m.

[Julf]

Originally Posted by jtwrace

Mine are dead quiet too as they should be.

Indeed - with a specified 124 dB SNR, pretty much any noise is an indication of some sort of abnormal issue.

[ChrisPa]

Robbby - testing with a shorted input seems like the starting point. They should be silent both in terms of pops and background noise.

There is a gentle click from the modules when they power up - not through the speakers

[robbbby]

Thanks for the replies guys.

I have adjusted the dc offset at both the input and output using r95 and r136. What does the third pot on the far side of the board do?

I guess I will also have to check all my grounding and wiring. I will take a picture when I get home from work and hopefully somebody more knowledgeable may be able to spot something troublesome.

ChrisPs - Can you explain the testing with a shorted input? I'm not sure I understand. Thanks.

[ChrisPa]

short the input to the power amp
turn the power amp on

there should be no pops through the speaker
THe general consensus is also that there should be no audible hiss too

If there's a pop - then it implies there's something awry with the amplifier
A click form the module itself (not through the speaker) is to be expected

If there's hiss then it also impies there's something awry

If the pops and hiss reappear when you connect your upstream equipment, then it implies they're being caused/generated by the upstream equipment