Basic surge protection with some noise filtering without strangling the amplifier?

I installed a whole house surge protector that clamps down fast and can take whatever happens to be flowing when the shut down happens, even a lightning strike.

Try the Richard Gray stuff.  Works great

Some really great advice on this thread.  I would add to it by saying: 

1. nearly everything you try unless you get into big bucks will, and does strangle the amplifier.  Going into a wall is best.   For digital sources, a power conditioner is your friend and can pay big dividends in sound quality. 

2.  For me I have occasional DC line noise, which would show up sometimes and sometimes it was fine.  My neighbor got solar panels and the issue got worse.  So, I am now using the PS audio whatever they call it and it's been superb.  It also has DC filtering up to 2v.   I have used power amps into that, but occasionally think I hear a difference.  Using class D power amps (red dragon) and Rogue tube preamp now and tubes and class D *seem* to be less power sensitive, but that could be now I've resolved all the power problems.  

hope this helps.  

Well, it’s early hours for the Furman Elite-20 PFi, with the 625 V2 and a REL Carbon Special plugged in to it, but I thought I’d report back that so far I notice no SQ or performance degradation whatsoever — with a decent range of my usual music, although have not tried any classical yet.  And it is nice to have some peace of mind should there be some building electrical system (elevator motors, HVAC, god knows what) surge or other issue that my much loved Rowling is more protected than it was. 

Thanks again everyone for sharing your experiences, hard-won insights & knowledge and suggestions.

I own the Furman Elite -15 PF i. I bought it primarily for surge protection and with the hope it would not make my system sound worse. I didn't necessarily expect it improve the sound of the system.

Listening to my system after installation I thought the Furman improved the sound. I wasn't certain whether it was just my imagination. Later that evening, my wife, who enjoys listening to music with me and has a good ear but is oblivious to my equipment - mentioned that she thought the system sounded better. 

So I would recommend the Furman for surge protection. You may or may not notice an improvement, but I don't think plugging your amp into it would hurt the sound of your system. And by the way, it provides very good protection in my experience. Experienced a bad power surge and the Furman shut off before any harm came to my tube amp (tube amps can be especially vulnerable to power surges). Turned the Furman back on and everything was fine. Best purchase I ever made.