I have a little setup that a PC connects to Yamaha 01V96 mixer.

I connected the mixer to the sound card using 3.5 stereo to 1/4" mono splitter cable. Since the cable is not balanced cable I am getting hum in the speaker.

How can I get rid of the hum? Is there any cable that I can get to change the the unbalance output from the sound card to balanced output?

  • 1
    You’re getting a ground loop. You need to unplug everything, then plug back in one at a time to determine the source / cause of the hum. Then you’ll be able to reconfigure your setup. Usually they run about 60 or 120hz. Dec 24, 2018 at 20:39
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    If the cause is a ground hum, then ground loop isolators can work very well to eliminate the hum. Or do you have an option of using S/PDIF ? Dec 24, 2018 at 20:50
  • I was actually using a sound card with ADAT, but it died. My current sound card has only SPDIF, but the Yamaha mixer receives only ADAT. That is why I am using the analog output for now. I think I would have to go with ground loop isolator until I get better sound card option.
    – Kay
    Dec 25, 2018 at 2:10

1 Answer 1


There are simple audio ground loop isolation adapters that are, in principle, nothing other than a simplistic DI box. As opposed to a proper DI box, they have unbalanced connections on either side. This will not give you the common mode rejection of a proper balanced connection, but your separated "ground loops" will then be the two-fold ground connection from adapter to mixer, and from adapter to laptop. Those "loops" are minimal compared to half the room and its wiring (which is what you apparently currently deal with).

Here is an example image:Audio Ground Loop Isolation Cable

A proper stereo DI box usually has two 6.3mm TS inputs on the unbalanced side and XLR outputs on the balanced side: you'd use that with the usual adapters/cables, it adds quite more bulk, and the quality is inherently better (due to the symmetric connections) as well as usually done with higher quality components (higher level tolerance, lower distortion, better low frequency transmission). If there is to be a long connection, it should be on the balanced side as that is quite more robust against noise.

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