Speakers buzz until console turns on..? Why?

holickpro · Post by **holickpro** » Mon Oct 15, 2007 12:45 pm

With the mixer off and the monitors on, there is a major buzz/hum. Not a big deal, I just turn my console on first, but I am still curious. If no signal is sent to the speakers, why would they buzz? I am sure there is a very simple explanation for this.

Thanks.

Don T · Post by **Don T** » Sat Nov 10, 2007 3:36 pm

Hello,
Generally it has to do with "loading" the circuit. Some devices use diodes to power supply to protect and center "ground." For sure the impedance changes when the circuits are powered. There is also the possibility of ground loops and lifted ground with the power off. Maybe your gear has a ground loop that only gets shunted when the common mode rejection (read balanced signal) is functioning. Since I don't know your setup I can not definitly say.

Most Studios have a "turn on" order.

barefoot · Post by **barefoot** » Wed Nov 21, 2007 8:29 am

It might be some type of relay circuit on the console outputs used to prevent power-up transients from popping the speakers. The cable ends may just be dangling on the mixer side until it powers up and closes the circuits.

Just a guess.

Thomas

Jannik Gade · Post by **Jannik Gade** » Fri May 09, 2008 2:26 pm

If your power cables to the speaker aren't grounded, but your mixer is, you can be cutting the ground to the speakers when turning off the mixer.

try getting power cables that are grounded..