Your most indispensable "tweak"?

So many interesting suggestions!  Thanks all.  And feel free to keep them coming...

@highend666 - thanks for the link, although completely impossible in my listening space

@stringreen - details of your carbon fiber outlet please?

@sjsfiveo - yes, couldn't agree more about NOS tubes

@soix - not sure what these jumpers look like in action -- can you describe more?

@barbapapa - not familiar with PPT -- what does that stand for?

@chrismini - super interesting suggestion

So many isolation/shelving ideas too -- will look into those.  Thanks!

Debrox > Deoxit.

Sacrifices to the Greek God of music Apollo. 

Details of Carbon Fiber outlet cover.....this is the most idiotic thing I ever experimented with.   Surely the replacement of a plastic outlet cover would have no effect on the sound.   I even tried to load the inside of the cover with Blutak....no difference at all, so I left it in place.   The outlets themselves are audiophile approved Maestro, the cable is Neotech with top of the line Furotech carbon fiber plugs on each end.  On a lark, I went to Ebay and got 3 carbon fiber outlet covers for the 3 outlets in the stereo room.   The covers are from HongKong (although they came through California, they were 20 dollars each, and the change was very dramatic all on the up side. 

Annual ear wax removal