I have been a stickler about keeping power cables away from signal cables...on equipment ?

I too try to keep all of my cabling as separate as possible, but to some extent one can only do so much. I think of it as a best practice type of thing. Might not really help, but certainly can’t hurt.

Correction Millercarbon, 'these things all make difference YOU think you can hear in a non-blind comparison.'

As we age...Rock on..

I toss em this way and that, until I get some hum, then it's a chase, sometimes a long one.

but only had hum from power twice in all the years, and way back when, fm antenna hum (college days, t shaped twin leads taped to something this way or that. coax to real fm antenna solves that.

Some people have endless problems with noise of all types.  Others seem remarkably lucky in never or rarely experiencing such issues.  I have worked in several fields where power cabling in proximity to signal cabling is an unavoidable fact.  No matter the industry or issue the basic rules and guidelines appear to be universal.  I will throw together a list of some of the most basic procedures I have come across.  Any updates, edits or clarifications gratefully accepted.

1. Cables carrying different types of energy or very different levels can and do interfere with each other debating that is counter productive
2. Distance can attenuate interference as effectively and perhaps more reliably than shielding, anything that helps helps
3. Twisted pair data cables are common as unshielded UTP or shielded STP but are all designed to cancel noise via the 'twist' so shielding is considered to be 'as needed' rather then a general panacea 
4. In the cable and broadcast worlds shielding for co-ax serves functions beyond the audiophiles concerns so yes foil, braid, foil and braid, double foil and braid and solid shell co-ax all perform differently but maybe not in ways familiar to the audiophile
5. Cables running in parallel present the greatest risk of interference those lying perpendicular the least, remember this when you are forced to have different types of cables near each other. Sometimes a tricky routing problem can be gotten around by simply dropping a speaker cable across a power cable at precise right angles instead of killing yourself trying to keep them apart. Not actually recommending this, keep them apart if at all possible but that's a slippery phrase as we all know
6. RFI can be so difficult that people have moved because of it but there is a clue.  Strong RF fields in one spot can often be hard to detect a short distance away and even standing nearby can make a change.  When you hear a local FM station through your phono stage the cables usually get the blame and they are usually guilty but sometimes they get help.  I had a MC phono stage that always played a local station whenever the input cables were connected.  Disconnecting the TT end, changing cable orientation, changing cables all made changes but nothing got rid of it.  When I swapped out the phono stage it was GONE!  Tried the cables that were worse earlier, moved them around etc. NO RFI.  So, lets blame the phono stage.  Except, the phono stage picked up no RFI unless cables were connected to the input so it looks like the kind of complex interaction that can drive you nuts (yes I know:))