Electric humming noise in speakers, probably from 2xRCA to 3.5mm jack cable | Any advice?

[skybellrock]

Hi,

I have an unorthodox setup. I have my computer connected over HDMI ARC to the NAD T748 receiver. Using the receivers RCA pre-outs I connect it with 3m 2xRCA to 3.5mm jack cables to two pairs of KEF LSX speakers for 4.1 surround (Awaiting one LS50 anniversary for center channel).

I have noticed an electric humming when the speakers are at 75-100 sound level (their own amp levels). The noise must come from either the cable or the contacts of the receiver. When the speakers are not plugged in but active the noise is not there, so it is not speakers self-noise. When the receiver is turned off the noise is still there. To be fair these are the cables I bought from Aliexpress. I know, chinesium and all that.

Before I go wasting money on more expensive cables I have a few questions:

• Is there really a difference in noise between these types of cables?
• What should I look for in this type of cable to ensure it does not pick up noise?

Thanks for any and all answers.

 

[Ian Wendt]

Unplug the HDMI cable from the PC, see if the noise persists.

 

[skybellrock]

Unplug the HDMI cable from the PC, see if the noise persists.

Hello,

Thanks for the suggestion. I figured out the problem. The cable passed near to a power extension which created strong interference.