Wierdest tweak not appreciated by others:
Stuffing the DAC with antistatic grey foam.
This tweak was first mentioned by a guy from Holland in Stereophile years ago.
I stuffed my first DAC an Adccom DA600, and was happy.
Then a used Adcom DA700 was out there for $250. so I bought it and moved the stuffing from the 600 to the 700.
I find it really does make a difference. The foam stuffing soaks up all the stray EMF, and makes the end product (music signal) cleaner.
The Antistatic foam (cut into small shapes to fit most of the nooks and crannies)is wrapped in thick plastic and fills the interior of the case completely, or, for under the main board separated from the electrical contacts with a thin cardboard sheet.
However, a number of folks have totally dissed this mod. Either because they think it is a fire hazard (in a sealed chassis?) or they must just not like it? Anyway, NO ONE has ever tried it from my mentioning it, at least not reported back that they did.
Added: I originally used antistatic foam sheets from Radio Shack, but last year bought large (40" by 40" professional black foam) from a wholesaler. It took months to deliver! but now i have a lifetime supply!
Als, supposed to work in CD player, but the interior of most CD players is a crowded, convoluted nightmare and i never did add any to a CD player, though I opened some up and looking at it's innards.. gave up. To even put some under the main board would mean disassembling the player. No Way!
DACs are very flat straightforward inside in comparson.
So... Antistatic foam qualifies.. It definitely qualifies as a wierd tweak.