Power cord? Why?

Does it make sense to use greater than 12 gauge for the power cord since the outlet itself to the breaker box is only 12 gauge? In most cases bigger is better. However, if the outlet can only give you 20 Amps then what's the point of using a 30 Amp power cord since your device is drawing less than 6 Amps anyway?

Anyone did A/B test with 12 gauge vs 10 or 8 gauge? I've compared 12 vs 14 and it doesn't make much difference. 12 gauge seems to give slightly better bass than the 14 but not by much. From my own A/B test, the difference is no greater than 2~3%.

Thank you Sean. I guess there is no point for me to change from 12 to 10 since I don't really have a dedicated line for my stereo system. The power cord I need is only less than 3 ft long anyway. Like what I observed from 14 to 12, there probably will not be much difference from 12 to 10 in this case.

Audioengr, tks for your reply. I'm using twisted pair of 12 total AWG wires. I was thinking about doubling that and get 9 gauge.