Noise/buzz/hum from USB cable

Question

Noise/buzz/hum from USB cable

I connect my Yamaha S90 keyboard to my iMac G5 to get MIDI data to GarageBand. Works fine BUT the USB cable introduces some fairly nasty noise into my studio setup. Unplug the USB, the speakers go back to nice and quiet.

Is a wireless connection a possible solution to this problem. If so, is there a device that would connect to the USB B connection on my keyboard and transmit wirelessly to my Bluetooth capable Mac?

Nothing worse than noise that's not supposed to be there. I'd appreciate any comments.

Thanks,

Scott

iMac G5, Mac OS X (10.4.3)

Posted on Dec 15, 2005 12:00 PM

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Answer 1

Dec 15, 2005 1:32 PM in response to Scott Alexander

I can't imagine the cable being the source of the hum. It delivers digital, low-bandwidth data to your computer. You are only transmitting midi, no audio?

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Answer 2

Dec 15, 2005 4:28 PM in response to Scott Alexander

Thanks Christoph, you helped to solve my problem but I still don't understand some things.

In response to your question, I did also have the S90 keyboard connected to a Mackie 1402 mixer via 1/4 in instrument cables. To repeat the symptoms, if I pull the USB MIDI connection, the noise goes away. Plug it back in and the noise comes back.

Your response led me to these two experiments:
1. If I let the USB cable still be connected but pulled the 1/4 in instrument cable audio connection, the noise was gone. Good info but no solution because I still want the connection to audio.
2. I replaced the 1/4 in cables with balanced 1/4 in lines. This solved the noise problem with the USB cable.

Not sure I understand the interaction between the 1/4 in lines and the USB cable but your response led me to the solution.

Thanks alot.

Scott

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Answer 3

Dec 15, 2005 10:57 PM in response to Scott Alexander

Good that my post made you check your cables again ... 🙂 Audio cables can pick up hums and noises in a lot of ways, they're basically antennas, and if there's one weak point in your chain, you can catch a lot of buzzes. That being said - I don't really understand how your system picks up the noise. Maybe trying a different USB cable with a good shielding is worth trying.

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Answer 4

Dec 16, 2005 7:19 AM in response to Scott Alexander

I have a Yamaha DGX-505 and I ran into the exact same problem. Whenever I have both cables plugged in I get the hum. It is a minor inconvenience, but at least we are able to get rid of it.

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