I own two large power conditioners. The 88lb Furman sits halfway between the amplifier (which is between the speakers) and the audio rack (which is near my seating) I used to use that PC for the amp too, not anymore, but too lazy to move it. It sits on the floor up on spikes. The other PS Audio P-600 is behind the audio rack..One comment on placing something ON TOP of a power conditioner... If it has a big transformer.. I would say you should at least have an extra inch of space added between the top and any component over it.
Another consideration is realize plugging and unplugging power cords.. plus if you use aftermarket thick and unwieldy cords.. Some racks block acess.. You make need to just put the power conditioner on the floor where you can allow power cords to fit without a hassle.Also if the conditioner is off the floor.. then the weight of aftermarket power cords and them pulling out of the AC outlets is a big PITA too. So all in all the floor is the best overall place for one. Maybe up on spikes to keep the bottom vents clear of the carpet.
Another consideration is realize plugging and unplugging power cords.. plus if you use aftermarket thick and unwieldy cords.. Some racks block acess.. You make need to just put the power conditioner on the floor where you can allow power cords to fit without a hassle.Also if the conditioner is off the floor.. then the weight of aftermarket power cords and them pulling out of the AC outlets is a big PITA too. So all in all the floor is the best overall place for one. Maybe up on spikes to keep the bottom vents clear of the carpet.