Prioritizing Power Cable Upgrades by System Component.

@imaninatural 

In my opinion the answer is - it depends. 
A power cord upgrade on DAC can make just as significant improvement as the right power cord would on the amplifier.
If your system is able to resolve the differences a power cord upgrades make I’d say DAC, pre-amp or amp…doesn’t really matter where you start however the subwoofer would be last on the list. 

Also, keep in mind that there are power cables that work better on DACs than they do on pre-amps or amps and vice versa. 

Just my $0.02. 
 

“the influence of the power cable is inversely proportional to the quality and sophistication of the built in power filtering and power supply of any component.”

That quote sounds good, makes sense. But my experience definitely does not confirm it, nor at first blush refute it. This would need to be backed up by lots of observations. I can think of lots of possible contra examples from my experience but most are confounded by some factor. But, better sounding equipment is much more sensitive to small differences… so I have my doubts… I would always test. 

OP, definitely power amp first with emphasis on current. Then (I think) source with emphasis on isolation… shielding. Then in between.

I'd probably agree with amp first, but then you only expose another weak link with each PC. In the end all equipment is important, but I guess you have to start somewhere, can only say I'm happy I'm done with it. I too keep previous upgrade cables, never know when they'll come in handy at some future date. But then I use this philosophy on everything in system, way too much audio stuff in house.

@carlsbad  - This sort of aligns with my experience of hearing a significant improvement with the $50ish W Audio power cable on my Pathos integrated amplifier, but not with my other components.