Best Power Cable Component Hierarchy

I would go ’upstream’ with cables, like power cords. Distributor, source, dac, pre amp, power amp. But every component reacts differently on power cords due to the quality of the power supplies and the influence shielding has on components and nearby cables. Sometimes components perform better just because there is less cross contamination. But source first gives the most satisfaction IMO.

The biggest difference in my system has been the power cord on my amp.

I agree to use your best cable to the power conditioner / distributor.  As previous posters have said, it is best to experiment since the response is component dependent.  And as suggested above, use smaller gage cables on low power components and larger gage for high power components such as amps.