Hi
I suppose a bad, loose connection can be audible ... Some connections can be so loose that one can see see sparks coming out of it when the equipment is drawing power. such problems are traceable and measurable.
Good honest tight connections shouldn't do that.. If one wants to be on the safe side, one could use, in the USA, Hospital -Grade outlets. They provide a very tight connection. Unplugging and plugging are difficult... The idea behind hospital-grade outlets is to make sure that the connection is difficult to break: imagine that the cord of a life support machine too easily unplugged from the wall outlet, someone trips on the wire of the life support machine and turning both the machine and the patient off ...
Once at that level is reached no clear difference. The rest is what clever marketing and our audiophile mentality almost compel us to believe .. Thus you see now an explosion of "audiophile" outlets with the most famous, cryogenically .. even cryo wires... and none are cheap with the current audiophile darling the Oyaide costing above of $200 when it is cryo-ed and cooked (I would suppose that such an inhumane treatment to the poor metal would have it lose all its organic sound but ..
). To make it even more interesting they have different faceplates, of course expensive too with carbon fiber and the appropriate audiophile price which means at least $100 .. FYI this FACEPLATE
cost without the outlet $379.99
..
Of course we, audiophiles, will hear these differences .. The only problem is that not knowing the presence of the Oyaide outlets makes us lose that exhalted hearing acuity but once we know we are listening to an
Oyade, such acuity quickly returns .. And of course it is superior to all other outlet out there, until some other company manages to convince us that their $ 750 outlet and faceplate combo is even better ...
We are , seemingly heading toward the $1000 outlet + Face faceplate combo .. Will wonders ever cease ???