The massive toroidal transformer in your Lexicon amp is most likely being effected/rattled by DC Offset ... the DC offset is being created by all the switching power supplies in your household appliance's and anything that has a remote control including your cable box/DVR and your flat screen
The DC Offset is created by the switching power supplies which use half wave bridge rectifiers that draw current in uneven pulses ... these uneven pulses will cause big toroidal transformers to rattle, buzz, or hum ... causing the transformer to lose some of it's efficacy and reducing it's headroom and dynamics ... not good in home theater
The DC Offset enters your amp through the power cord so disconnecting ICs and speaker cables will have no effect as the pulsing Offset is entering on the power line ... switching power cords will not help either as they merely act as a conduit to the Tranny
I've also never seen a power conditioner that deals with DC Offset ... although Bryston does incorporates a DC Offset blocking circuit in some of their amps
Channel Island and PS Audio offer units that may be worth looking into
The DC Offset is created by the switching power supplies which use half wave bridge rectifiers that draw current in uneven pulses ... these uneven pulses will cause big toroidal transformers to rattle, buzz, or hum ... causing the transformer to lose some of it's efficacy and reducing it's headroom and dynamics ... not good in home theater
The DC Offset enters your amp through the power cord so disconnecting ICs and speaker cables will have no effect as the pulsing Offset is entering on the power line ... switching power cords will not help either as they merely act as a conduit to the Tranny
I've also never seen a power conditioner that deals with DC Offset ... although Bryston does incorporates a DC Offset blocking circuit in some of their amps
Channel Island and PS Audio offer units that may be worth looking into