AC Conditioners: Must Have Tweak or More Voodo

As the old school, 2 channel, sentimental dinosaur that I am, power conditioners are very newfangled devices to me and are filed in the same section of my brain as home theatre receivers. However, I have just moved into an apartment in an old townhouse where half the plugs don't even seem to work and even the ones that do requie "cheater" plugs. As I continue to build a system around a Levinson 23.5, ARC SP-11 MK II, Michell turntable and Sony SCD-1, I am wondering if some of these devices would erase my worries about old wiring in the house. Can someone please educate me on what I should do? Dealers seem to tell me that the power amp should go into the wall or a chang lightspeed thingy and that PS Audio 300 would be good for all the source components but I'm clueless. Would these things really mitigate the need to rewire or seek a dedicated line? Thank you.