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I've got a dozen older DP-DMX20L units that are sending noise back into the electrical system and ultimately showing up in the sound system.  Goes quiet at 0, 50 & 100% and the closer to 25 & 75% the louder the hum.  Is this simply inexpensive dimmers or should I be looking elsewhere?

It should be noted that ALL audio signal cables are balanced XLR type, everything is powered from the same panel with the same ground (I know, I installed it.)

I actually didn't have this issue when I used a separate source for the lighting power.

Last edited by joegardner
Original Post


It Looks you're experiencing electrical interference issues in your lighting system, affecting your sound system. This is likely due to inexpensive or older dimmers. The noise is most noticeable at specific dimming levels and disappears at 0%, 50%, and 100%. To resolve the problem:

  • Consider dimmer quality and upgrade if necessary.
  • Ensure you're not overloading dimmers with excessive wattage.
  • Physically separate dimmers from audio equipment.
  • Verify proper grounding to prevent ground loops.
  • Use isolation transformers for lighting circuits.
  • Invest in power conditioning equipment with noise filtering.
  • Confirm proper shielding of audio cables.

I hope You can find the solution if you take these steps


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