Speaker buzzing …

Hello there I have noticed that I have a buzzing/ distortion noise on my speakers above half volume and As I turn the volume up the noise gets louder after halfway volume when I have my LP12 switched on if I switch to cd input the noise only starts around three quarter volume and only rises a bit as the volume is increased but is nowhere near as loud as the LP12 aux imput …I don’t play much more than two thirds volume so under normal playing volumes it is not a problem but I would like to get it sorted if I can !. And hopefully it is not causing any harm to my speakers . Any suggestions welcome ?
The system is
Linn LP12
Niam CD3
Niam nac 92
Nap 90

When were your Naim 92 & 90 last serviced…?