Noise, Noise, Noise

[kupgas@aeneas.net]

I know this subject is probably beaten to death, but it still plagues me. I am using two UPS backup batteries to power my studio equipment and I still have this annoying "60 cycle" hum coming through. I'm using good cables, and I've tried dropping the ground on every power cord to no avail. I'm not picking up any radio stations, but this hum is frustrating. Any help or links to articles would be a great asset.
Thanks
Kupgas

[Audioholic]

is your UPS also filtering the AC, like what a furman would do? You may need to clean out your AC, also can you pinpoint if the buzz is coming from any partiulair source, like for instance, remove each cable to see if its gone...

[dpd]

Start with just your amp connected to your speakers. Then connect amp to whatever drives it. Then plug in ONE piece of gear, etc, checking the buzz as you go along. Does it all come on at once or is the increase gradual?

Sounds to me like you have a bad ground on your AC service.

[Steve Kerman]

The UPSs are likely causing a lot of your hum problems. Most inexpensive UPS systems generate a stepped waveform instead of a pure sine wave. The harmonics of that stepped waveform are much more likely to bleed into your equipment than a pure sine wave is.

[kupgas@aeneas.net]

Thanks for all the tips, men. I've gotten most of the 60 cycle stuff out by using a ground eliminator on a few of the power cords. I know that's not safe if something fails, but at least I'm finding out what units might be inducing most of the noise. It's amazing how much noise the central a/c makes when I "listen" to my condensor mic (48v) through the board with headphones.

Now that most of the noise is gone I'm finding the most coming in when I patch the board to the adat. The adat has rca inputs, the board has left and right XLR's as well as rca record out jacks. I'd like to make balanced cords, but without two connectors and a shield on the rca side, it seems impossible.

How do I check to see if my power company's service is properly grounded? I though about running a dedicated 110v line from the box to the studio upstairs just to isolate everything to one circuit.

Any suggestions would be helpful.

Thanks,
Happy 4th of July
Pray for our troops.
Kupgas