Odd Hum Problem

[EricTheEZ1]

I've been slowly gearing up for recording on my computer direct from my amp.

I have a Workingman's 8004 Head and a Soundblaster Live Drive that I use the front Line-In 2 input on.

I tried using an instrument cable to go from the amp (Preamp Out) to the PC and it had HORRIBLE buzzing that came through in the recording AND the amp.

My friend gave me an XLR to 1/4" to try out and I connected it to the Balanced Output to Line-In 2. There's still hum coming out of my amp's speakers but much less (a few decibles of hum) in the recording. When I use the ground/lift switch, it cures the humming of the speakers but the recorded signal has something like 30 decibles of hum. It goes freaking crazy.

Anybody know what's going on here? Why would my speakers pick up sound from a one way output connection? Please help me.

-Eric.

 

[DemoEtc]

You're getting the hum even with the bass unplugged?

If not, could it be the pickups being unshielded or some stray line noise coming from wiring in the walls/floor?

 

[Selta]

Sure you're not using a stereo plug where there's only a mono jack? I did that a few times, got something similar to what you have going on.

-Ray

 

[EricTheEZ1]

The bass isn't the problem. I've gone direct from Bass -> PC with no noise. If the connection is made between the amp and the PC, it hums. What's wierd is how the noise is coming through the AMP as well. I mean, the Preamp Out/Balanced Out...they're OUTPUTS.

I don't know if it's a stereo plug. I've used 1/4" to 1/4" that were instrument cables and I'm now using an XLR to 1/4" that is a friend's microphone cable. I *think* it's mono (1 black band around plug). How would I go about getting rid of that hum coming from my amp?

-Eric.

P.S. - I have been looking into getting a Sansamp Programmable Bass Driver. I know it's more than just a tone box, but a DI as well. Would the XLR out on the DI elimate most/all hum?

 

[Selta]

Did you try the input on the actual card, then? On the back of the PC instead of the front? That might be part of the problem as well.

-Ray

 

[EricTheEZ1]

I would have to use a 1/4" to 1/8" adapter since there's no 1/4" on the back/actual sound card. Wouldn't that reduce sound quality?

-Eric.

 

[Selta]

I would have to use a 1/4" to 1/8" adapter since there's no 1/4" on the back/actual sound card. Wouldn't that reduce sound quality?

-Eric.

Nope, that's what I do currently.

-Ray

 

[Lyle Caldwell]

Are your computer and amp plugged into the same outlet? Sounds like you have a ground loop.

 

[DaveMcLain]

I would try lifting the ground to see if that cures the hum problem. You can do this quickly by using an adapter at the AC outlet where your amp is plugged in (not the safest way). Or you can take a cord and lift the ground by cutting the shield loose at ONE end. Using that cord between your amp and computer allows the signal to travel through a shielded cable without providing a ground path through the shielding that induces hum. Most of the time it works best if you can attach the shield at the quiet end, probably the sound card, give it a try.

 

[EricTheEZ1]

I already have a ground/lift switch on my amp. When I use it, my amp still hums, but the recording has minimal hum. It's actually not that horrible, especially since I can use a simple noise filter and it's pretty much all gone. The amount of hum I get is similar to using an amp mic. Almost reverb like, in the mix.

Like I said, if I don't use it, there's no hum in the amp, but a TON in the recording. I think I'm gonna accept what I have until I can get a DI box since that would cure the amp's hum, for sure, and it would most likely reduce the recording hum to even less/nothing.

Thanks for the help, everybody.

-Eric.