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

BTW, while I do think protection from brownouts is important (EVS in Furman lingo) it's particularly bad for switching power supplies.  A brownout can cause a transistor intended to be high efficiency/binary to turn linear and low efficiency, burning it out.  

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.