I have seen no real sonic improvement to my ears with the power conditioners I have installed on my systems. Bear in mind that the system can theoretically draw quite a bit of load, but only for short durations. For instance the 7700 could possibly draw all 7 channels into 4 ohms at 300 plus watts per channel. That all by itself is more than 2 KW. In reality though the whole system will only draw a fraction of that power because we don't ever run the amp at full load for very long and likely only the front main channels are drawing significant power. The protection afforded to my systems from those conditioners is what I bought them for and they do that job quite well. I live in South Florida and get a lot of lightning strikes every year. The systems have acted several times to shut my equipment of with out damage. At least once lightning struck right outside the house and took out two 70 foot palm trees by going down one and up the other. That power passed through the ground where my house is grounded and my equipment would have been fried otherwise. The only benefit from improved performance I have noted is that I have more than 10000 hours on my DLP projector bulb and it is still going strong.

As far as amplifiers and other gear having power conditioners, it is partly true because the power supplies in good gear is designed to work with varying voltages during the day and automatically adjusts to the condition at the wall socket. However, that wall socket could be faulty or not supplying the right power which the conditioner can either help overcome or at least tell you there is a problem.