Silver plated will be of zero benefit when you are dealing with 60Hz AC. The skin effect becomes a factor three orders of magnitude beyond that. Litz is also wasted on 60Hz for the same reason. All you need is stranded copper of sufficient ampacity for the load. For example a turntable consuming a steady 35 watts is more than fine with an 18AWG cord. A power amplifier rated to consume 300 watts might consume brief peaks 25% higher than that, and is still adequately served with an 18AWG cord, (remember that peak of 375 means 3.3 amps at 115 volts), but it “feels better” having a heavier cord, so manufacturers usually bump it to a 16AWG. In fact, a little resistance in that power supply cord is a benefit, since we can put a nice, low impedance RFI filter in the power supply input stage, we need something upstream to sink that noise. So when you are looking at power cords, remember these things and that the old adage “all that glitters is not gold” holds true here too.
