SoX and Audio Unit give scratch

Hi,
I use the Linear Tilt Eq from Kock-Audio with a great pleasure … but if I enable the SoX X2, X4 … the playback give scratch noise … Is there a special SoX setup to give a perfect playback ?

Thanks to all

What is USB cable you are using now? I ever had the noise problem like yours when I used normal/ standard USB cable for PC to my DAC 24/192KHz. After I change to USB from Chord Company (USB Cable with Audio grade), the noise disappear.