Power supply to Amplifier

I use Furman Elite PFi 20 conditioner. It has very tight non-sacrificial over/under voltage protection with circuit breaker. It provides separate filtered outputs for power amps, preamps and video. I don't experience any loss of dynamics perhaps because it uses Power Factor Correction - that consist of huge inductor and capacitor. By storing energy they not only smooth-out supply current, making it look like resistive load, but also can deliver large peak currents to load (55 amperes max). If I remember correctly Elizabeth uses Furman Reference series conditioner that is even better, providing complete isolation and therefore additional common mode noise suppression.

Rlwainwright, you're right - it won't do a thing when lightning hit is direct (1 foot wide plasma) but it will help when it hits transformer, street light, ground near your home etc. The best is always to unplug and I do it during thunderstorms or when leaving for few days. For everyday use my amp is ON all the time protected by Furman. My DVR and TV are also plugged-in since it is recording shows during day.

Also, Al has very good point. It doesn't have to be lightning. I experienced few times light bulbs going slightly brighter for a second or so and in one case Furman's circuit breaker switched off. Voltage reached dangerous level without any thunderstorm in whole area. Such things like inductive kickbacks, that Al mentioned, would not be noticeable but could easily damage electronics. My Furman filters them out and suppresses them without even engaging circuit breaker.