QSC K8.2 problem

[HalfSwede]

Thanks Frantz. Not done firmware update for a while. Will do that but I think unlikely to change things as buzzing is mechanical sounding rather than electronic. Really appreciate you testing your K8.2 In Sample Synth play bass sound such as Fend Prec Direct without any effects/EQ direct into K8.2 using Default pre-set. On mine buzzing worst on A below middle C semitones adjoining and then octave below. Buzzing audible modest volumes ie Nord Master Volume at 50%, K8.2 50% and Sample Synth -3.5db. Does that give you enough detail? If you do get buzzing then then experiment changes to Nord EQ, K8.2 DSP settings and if you have mixer or DI to see if that makes a difference. Thanks again