Bought two of the Neotech NC-P311 (12.8mm, 14mm, 16.5mm, 18mm) Cryo treated Gold plated UPOCC Copper Male AC plug from Sonicraft for $23.95 each. Replaced the AC plugs I bought at Lowes that I used when I built my two balanced isolation transformers. These originally retailed for $70 each.
Wasn't sure what to expect, but after around 6-10 hours of burn in I can say that the overall sound is a little smoother, micro detail a little better.
Recommended; no affiliation with SC.