The Ksa should not hum, mine does not. Do you have the shorting pins installed in the balanced inputs when using single-ended inputs? If not...get some from Krell or it will hum.
On the other hand, maybe some Ksa models do hum? Mine is KSA-250.
Dave
On the other hand, maybe some Ksa models do hum? Mine is KSA-250.
Dave