Cleaning up AC ie. RFI EMI ,suggestions?

[b mcgibney]

Alot of the stuff I record is pretty low volume so anything I can do to lower the noise floor helps alot. I just finished copper foil sheilding all my guitars and that has made quite some difference for recording those instruments but it is obvious that there is still a lot of hash either being radiated or carried by my AC supply system. With the single coil guitars in particular, it does not matter where I stand in the studio, only by holding the guitar in a certain position can I get it to be quiet. Is this EMI or RFI? I live in a suburban part of the city with no big industry around. Also FYI my house is old ie. 85 years but was completely rewired 20 yewars ago to code.

My entire studio is running off one 15 amp circuit. All my rack gear is is in a 6 foot tall open frame metal rack. The main breaker box for my house is behind one of the walls of my studio (can't do much about that). Using a polarity tester I've confirmed that everything is wired correctly. My search (type power line conditioner) into google yielded many results and solutions ranging from 29 dollars to stuff in the 3 k range. I'd be keen to hear from other DUC members about there tricks for keeping the studio as quiet as possible. FWIW I have access to some big copper rods and heavy wire and i'm not afraid to drill holes in walls. I have a soldering gun and I know how to use it

On a somewhat related topic has anyone tried using those Radio shack isolation transofrmer on the mac audio outs to limit the amount of computer noise that gets into the audio chain?

Any links /suggestions appreciated---as always

Brian

[b mcgibney]

The single most important thing is a good ground connection for your house and studio. Ideally they are on individual feeds
but since they are probably not, once you get everything plugged in with the best ground scheme you can provide, go around
your house and unplug all the items in your house that you can, now listen and see if there is any difference in the studio's
accumulated audible noise. You'd be surprised what puts hash into the AC lines.

Would some sort of a AC filter help then at the head end. As I said earlier everything in my my studio is powered off a single AC plug with the exception of the Mac and firewire drives which are plugged into the other duplex plug. I had originally thought that was the only thing on that circuit but it turns out that is wrong, So a dedicated circuit from the main panel is the first thing I am going to do


Would it be of any use to drive a ground rod into the earth and tie that to the utility ground or alternately undo the ground connection from the main AC feed supplying the studio and use the ground rod as the ground connection for the studio? ie, disconnect that one circuit from the panel ground and use a true ground. I remember years ago in my parents bathroon if you touch the drain plug and the taps at the same time you would get quite the tingle. An electrician came and tied the supply and waste sides of the plumbing together and the problem was gone although I guess there was current flow between the two systems. SCARY! now that I think of it.

Having done that procedure, try physically and electrically isolating the various audio components one by one to determine
which are the most problematic - no doubt it will be your computer.

My computer is in another room. There is definitely some computer noise when I plug the mac audio outs into the external mixer. Some days things seem worse than others --weather?-- Also the CRT is quite close to the DIGI 001 . I often record with it turned off. Obviously a LCD would help--its on my list of upgrages

FWIW I would characterize the noise I'm getting as more buzz than hum. I'm going to take an ohn meter and see how much resistance exist between the ground @ the plug and the farthest thing plugged in ie the ground pin at the end of tha last power power strip.

THANX for your input

[hansvanriet]

The Sony Oxford Noise plug ins (Restoration Tools) are excellent for tracks with noise and clicks that are hard to filter out.

[sndchck]

i get the same problem only when my monitors on or if i'm close to it with my guitars. i just turn it off when i do my final takes.
Obviously though, there's gotta be a way to not have this problem.

[MissHiss]

Have you considered a wireless system? You can get a male-to-male 1/4-inch adapter on the receiver and have absolutely no wires at all. I used to literally hear radio stations on my Marshall until I got a wireless system.