humming like mad -- help!

[lilcapn]

hey --

i'm using an 8-track reel to reel, tascam, and a soundcraft board, ready to mixdown, got everything set up and routed, and of course then i notice the freaking HUM that's just about louder than any one thing in the mix.

i've searched and read other threads about this and know to keep power cords away from snakes, etc.

i assume it's a ground loop hum, it sure sounds like it, and i kind of think that there's going to be no way to get rid of it running stuff through the various effects ancient (space echo) and modern (distressor) and in between (lovetone pedal), some of which are unbalanced, some balanced, etc.

two questions:

since my tape machine is unbalanced, no matter whatever else i do, will that factor ALWAYS give me ground loop hum problems?

and

i don't have pro tools or any computer mixing software, but in those set-ups, is there some kind of "hum cancellation" plug-in or something that people use? maybe that's just wishful thinking..

thanks!

[TexRoadkill]

Plug everything into the same electrical outlet. If that doesn't work than try a ground lifter on the different devices until you can kill it.

[Sennheiser]

What Tex said, but do it systematically. Lift the ground on each piece of equipment one at a time until the hum is eliminated.

When I first started to upload to NWR.com, I had a bad ground loop problem with my set up (which is very similar to yours) whenever the stereo mains were hooked up to the computer sound card. I lifted one ground at a time with each piece of computer hardware and the hum gradually faded. The biggest culpret was the CPU itself.

Before that, I had a problem with a compressor. I lifted that ground and all was quiet.

My two signal snakes to and from the recorder and outboards at times have to cross the AC cord for my TASCAM mixer as it is on a rolling platform. I built a small "U" shaped box, open on the bottom, lined with two layers of foil coated bubble wrap. When the two snakes have to cross, the AC cables are covered with this box and the snakes lie on top of it at a 90 degree angle.

Never have had a problem with AC induced hum.

[lilcapn]

cool idea about the u-shaped box! my cords are definitely crossing at times as well.

time to start systematically working through all the devices that are up and running to find the humming bastard.

thanks!

[lilcapn]

one ground lift on the board itself, and bye bye hum!

seems like cheating at best, dangerous at worst, but i've got a quieter mix so i'm sticking with it!

thanks again, board.

[muhairwejas]

Hey Lilcapn,

What steps exactly did you go through. I've had that nasty hum for ages and it's almost made me give learning the art.

I also dont quite get what Tex means with ground lifting. Would you elaborate more please.

James

[lilcapn]

i just used one of those 3-prong to 2-prong plastic adapter thingies on the power supply for my board.

it came back yesterday when i had stuff running through this old reverb unit; guess i need a few more of those ground lifters!

[sjjohnston]

Originally posted by lilcapn
i just used one of those 3-prong to 2-prong plastic adapter thingies on the power supply for my board....

That's great, but uhm ... just don't touch the mixer or anything.

Actually, you'll be fine so long as nothing breaks. And even then, it might not kill you.