Interface issue - can you help me?

[famous beagle]

Just got a Tascam US-122 off ebay. Supposedly in perfect working order, etc.

The drivers seem to install perfectly (got the latest one from Tascam's site), but I'm getting a whining noise from my monitors. My monitors aren't making this noise by themselves when turned on with no signal cables.

A few weird things:

1. The noise doesn't change in volume when I turn up the line out knob (which controls the signal to my monitors). It stays the same regardless.

2. The noise is not present in the 122's headphone jack. It's quiet and clean as a whistle.

3. The noise changes levels depending on what I'm doing.

Check out the attached file where I recorded the sound with my iphone held up to the monitor speaker.

It starts out with no programs running.
Around :06, I open Reaper, and the noise gets louder.
Around :19 or so, I open up a Reaper project, and the noise gets louder and nastier (additional static, etc.)

Does anyone have any clue what the hell this could be?

I'm running Windows XP SP 3.

Thanks!

 

[JimmyS1969]

I used to have this noise. Can't remember what I did to fix. It was an old computer and a long time ago. I think it was changing to balanced cables to monitors from interface, or at least making sure they didn't run parallel to power or USB cables. I just don't remember.

Still XP still huh? I can't help much there...

 

[famous beagle]

Thanks for the response Jimmy. The Tascam only has RCA outs, so a balanced cable wouldn't do anything, would it?

I don't have the signal cables running near any power or USB cables.

 

[TimOBrien]

Do you have everything plugged into the same electric outlet? (you should)

 

[JimmyS1969]

Thanks for the response Jimmy. The Tascam only has RCA outs, so a balanced cable wouldn't do anything, would it?

I don't have the signal cables running near any power or USB cables.

Naw, unless the out's are balanced, it won't make a difference.

I wish I could remember exactly what the issue was. It was a desktop and USB connection. It could have been using a different USB port for the interface. I just don't remember man. Sorry.

It could possibly be a ground thing like Tim mentioned, but I never had anything plugged into a different circuit ever myself. Sorry I can't help more...

 

[famous beagle]

Tim: Yes I do (though I tried plugging into others just to see and still had the problem)

Jimmy: Ha! I thought the same thing but always kind of wondered because I don't think I've ever tried it. But I guess we can finally put this one to rest. I figured I'd try balanced cables just for the hell of it and see what happens.

So I ran an XLR-to-1/4" TRS cable from the monitor (XLR end) to the interface (1/4" end) and just used a simple female 1/4"-to-male RCA adapter to connect to the interface's RCA output.

Guess what? Problem solved. Noise gone completely! I didn't think it would make a difference either, but I guess you can't believe everything you read!

Thanks so much!

 

[JimmyS1969]

Well then, I have learned something new also.

I suppose even with the shield not being connected, it seems it is still giving block to interference. This may change some recommendations I give here. From the monitor side? Now I am curious...

Glad you got it sorted man!

 

[bouldersoundguy]

I suppose even with the shield not being connected, it seems it is still giving block to interference.

It's probably the ring/cold/pin 3 that's not connected at the send end. But that doesn't matter: the common mode rejection will work because the cold picks up the interference with opposite polarity so it still cancels the noise when received by an active balanced input.