I went to the local music store to look for a power conditioner for my new rig (rack-mounted Yamaha CP2000 poweramp and a Sansamp RBI preamp). The salesman told me that power conditioners are not made for power amps and that I shouldn't use one, or I might damage my amp. I've never heard that one before; is it true? I used the SEARCH feature and many people said a good power strip with a high joules rating will work just as well. What is considered a high joules rating?