@jea48 is the best there is for troubleshooting hum. You need to follow his instructions to the letter. Remove the power conditioner from the system. You should only have the monoblocks and the preamp hooked up and plugged into wall receptacles.
Krell KAS amplifier hum
The amps are directly plugged into their own dedicated 20A outlet. Is there a "conditioner" I can use to minimize/eliminate the mechanical hum I'm hearing through my MBL 111f speakers. I'm not looking for a multiple outlet item, rather, one which plugs directly into the wall and into the back of each monoblock. Please advise and thank you in advance.
Best,
Jose
Best,
Jose