you need a product similar to the SOLA regulator. This is a ferroresonant transformer regulation device with a buck/boost tertiary winding which does the actual voltage regulating. They come in many models with different size power capacities. Might be a good idea to use a smaller device for the source components & a separate larger one for the amps. I have no experience with them in regard to audio applications, but we commonly use them in the telecommunications electronics industry.
The design will help to suppress line transients as well as regulating the large voltage swings, however for better/faster clamping of large voltage spikes (such as during a thunderstorm if you are not home to unplug the equipment) you should have an AC line conditioner with an integral transient snubber. Typically I recommend the Chang Lightspeed line of AC conditioners, which both cleans up the line noise/hash, and contains a large internal MOV (metal oxide varistor) to soak up those big damaging voltage spikes. The 9600 is a nice large capacity model that will handle all your equipment. Myself: I use a small model 2500 for source components, & a large model 9900 amp, for my high power amps.