I don't think that my Furman PL-Pro E is manufactured anymore, I believe that they were around £450 originally, but it was a fairly high class unit in its day! If memory serves it can power 8 units. There are fairly cheap devices that power only one or 2 units, and as technology has improved the price has fallen. However, if your mains is really that noisy it might be worth trying to find out what is causing the noise first. Fridges are often a cause of noise for example. Go round the house and unplug things one at a time, retry your amps, and see if there is an improvement.