hercules djcontrol inpulse. damn background noise.

in our recording studio we needed a small dj console to test our songs.
we bought the hercules djcontrol inpulse 200 console on the amazon site.
when we connect the console from the speakers (presonus eris e8 + yamaha hs8) a loud background noise comes out.
we have no electrical problems, everything is wired to the "state of the art", but connecting the hercules djcontrol inpulse 200 console there is a strong background hum.

our tests:
- we changed the cables
-we changed usb port
- we tried to connect it directly to the sound card
-we tried to connect it to the "mackie big knob passive" controller
-we have always used great ts-rca cables.

but the noise in the speakers remains.
could it be a factory defect?
should i send it back?
thank you
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nel nostro studio di registrazione avevamo bisogno di una piccola consolle dj per testare le nostre canzoni.
abbiamo acquistato la console hercules djcontrol inpulse 200 sul sito amazon.
quando colleghiamo la console dagli altoparlanti (presonus eris e8 + yamaha hs8) esce un forte rumore di fondo.
non abbiamo problemi elettrici, tutto è cablato allo "stato dellarte", ma collegando la console hercules djcontrol inpulse 200 si avverte un forte ronzio di sottofondo.

i nostri test:
- abbiamo cambiato i cavi
-abbiamo cambiato la porta usb
- abbiamo provato a collegarlo direttamente alla scheda audio
-abbiamo provato a collegarlo al controller "mackie big knob passive"
-abbiamo sempre usato ottimi cavi ts-rca.

ma il rumore negli altoparlanti rimane.
potrebbe essere un difetto di fabbrica?
devo rimandarlo indietro?
grazie

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lenovo w540 notebook
windows 10 pro
intel corei7-4930mx
20gb ram

Hello,

Welcome to the forum.

1) Most common cause of background noise on USB-bus-powered audio device: noise of the computer power supply 

• To test it
  If the computer is a laptop, disconnect the computer power supply to operate on battery
  - if the noise disappears, the noise comes from the power supply,
  - if the noise does not disappear, the noise does not come from the power supply.
   
• To avoid it 
  Add a USB hub which has a power adapter between the computer USB port and the USB-bus-powered audio device.

2) Very common cause of background noise on audio devices: saturation 

• To test it
  On the controller: set the master volume on the controller volume knob below 50% of the travel of the volume knob, set the High (treble) knob at the central position (50% of the set High frequency potentiometer travel), set the low (Bass) knob at the central position
  On the speakers, set the volume below 40% of the possible volume
  - if the noise disappears, the noise comes from saturation,
  - if the noise does not disappear, the noise does not come from saturation.
   
• To avoid it 
  Never turn knobs to the max: it is a bad audio setting and you may damage your speakers.

3) Possible cause of background noise: ground loop, caused by a power outlet not properly grounded  

• To test it 
  Take good headphones (as good as the speakers or better) and check if you hear the ground noise in the headphones.
  - If you cannot hear the background noise in the headphones, the noise may comes from a ground loop (difference of potential between the ground of the power of the computer (and then the power ground of the audio output of the USB-bus-powered audio device) and the ground of the power of the speakers.
  - if you still hear the background noise in the headphones, it is not related to a ground loop.
   
• To avoid it 
  - Check your power connection (power plug, electrical power strip)
  - Move your equipment in another room and power your computer and speakers in another room. If your house is an old house, test in another house.