John Sayers' Recording Studio Design Forum Archive

Living with this frustrating noise that I think is EMI.

It doesn't matter if I move away from my computer monitor. I've tried turning all dimmers off to see if that helped an no difference. I've shut the circuit off in the studio and plugged into a different circuit (with no dimmers on it) and no difference. Used different guitars, different cords, eliminated everything else from signal chain, tried different amps, checked the circuit for bad ground.

The only thing that eliminates the hum is if I face a specific direction or 180 degrees to that direction.

Any suggestions?

Have you checked your grounding scheme? Do you have proper "star grounding" in your studio? If not, have you checked for ground loops? Have you checked that the building ground is good, and that all your equipment is properly grounded, for both signal grounds and also electrical grounds? Have you tried using a 100% battery powered system and killing all the power in the building, then turning on the circuits again, one by one, to find out which circuit is causing the problem?

Lots of things to try still....

- Stuart -

Soundman2020 wrote:Have you checked your grounding scheme? Do you have proper "star grounding" in your studio? If not, have you checked for ground loops? Have you checked that the building ground is good, and that all your equipment is properly grounded, for both signal grounds and also electrical grounds? Have you tried using a 100% battery powered system and killing all the power in the building, then turning on the circuits again, one by one, to find out which circuit is causing the problem?

Lots of things to try still....

- Stuart -

Soundman2020 wrote:Have you checked your grounding scheme?

No I haven't. Honestly, not even sure what it is. I have all of the audio equipment in my studio plugged into a single outlet. If that's of any help.

Soundman2020 wrote:Do you have proper "star grounding" in your studio? If not, have you checked for ground loops?

I have all of the audio equipment in my studio plugged into a single outlet. Wouldn't that eliminate ground loops?

Soundman2020 wrote:Have you checked that the building ground is good, and that all your equipment is properly grounded, for both signal grounds and also electrical grounds?

No. Would I need an electrician to do this?

Soundman2020 wrote:Have you tried using a 100% battery powered system and killing all the power in the building, then turning on the circuits again, one by one, to find out which circuit is causing the problem?

No. Could this be done by using a battery powered guitar amp?

I have all of the audio equipment in my studio plugged into a single outlet. Wouldn't that eliminate ground loops?

It should, in theory, but there might be other grounding paths that you didn't notice.... And it is possible (but unlikely) to have potential differences along ground paths from other causes too, such as induction from nearby power cables.

Would I need an electrician to do this?

If you don't know how to use a multi-meter to test that, safely, then yes, get an electrician to do it.

Could this be done by using a battery powered guitar amp?

Definitely! Kill the power to the entire building at the main breaker, and try playing your guitar like that. If you still have hum, then it is not coming from your place (neighbor?), but I'm betting that it will be completely gone. Then you can put the main breaker on, trip all the sub-breakers, and put them back on one by one, to see which one is the culprit.

Afterwards, don't forget to re-set all your alarm clocks, timers, and other devices that might not be happy about losing power!


- Stuart -

How about in a different room or better yet a different building?
Some guitars are very sensitive to EMI fields in the air. That's why turning or moving the guitar changes the noise.