Bluesound Node distortion/clipping

Hello world!I have just recently picked up a Bluesound Node (2021 version). I was very excited to get her all hooked up and streaming some hi-res audio however once I had it hooked up immediately noticed distortion/clipping at any volume in the midrange (female vocals, piano etc). My setup for the unit is as follows -

Bluesound Node ---> RCA Out--->Sansui AU-317 (AUX input)--->KEF LS50s

I have searched far and wide for answers on this - It appears others have experienced similar issues and they seem to have solved it by lowering the output volume on the BS however I have done this and the problem persists. I didn't have this issue prior to adding the Node and my turntable plays fine as far as I can tell however it's difficult to compare as i don't have the most troublesome tracks on vinyl. I have also tried different inputs, cables, channels, volumes and streaming services. I'm about to get an external DAC so will test with this as well once I have it.

Is it possible that the Bluesound is outputting a too hotter a signal for the amp or is the amp not capable of driving the Kefs and I'm only just noticing the impact due to playing around with different music because I have a new toy?