Which of these power cords ?

On the contrary, the power cord is the first 3 to 6 feet outside of the component that alters the performance.

In my system Power Chord swapping is easy to hear the differences...the same power cord on my DAC can sound vastly different on my preamplifier and again on my amplifier. I enjoy trying new power cords and have collected a lot of them. The Black Sand Audio is a great sounding cord on all my equipment and at a fair price...I purchased mine used in good condition. 

 I have an audio only subpanel with 8 dedicated circuits of 20 amps each per outlet in the listening room isolated from the lighting and HVAC servicing the room which goes to another subpanel.  The audio power outlets have Synergistic Research Blue duplexes.  The wiring is 10 gauge.  I built the room for listening purposes only.  The 42,000 LPs/78s/CDs are housed in an adjacent storage room and record storage Tuffshed.

I have the DH Labs Red Wave power cable on my amp. It's the biggest single improvement I've ever experienced, I was amazed.

Yes, at least 2-4 dedicated home runs of 15/20 amp 10/8 gauge wiring and hospital/audiophile grade outlets to the audio system is a big improvement—I’ve done this twice in the last two homes I’ve lived in (one was a rental with my landlord’s permission) and the results are amazing—easy to listen to/hear over the standard outlets. Both electricians thought I was “nuts” and I got them to listen to the “outlets” after the install and the amount and impact of the bass response on my 200 watts Class A amplifier was easily discernible to their “non-audio file“ ears, and they admitted they would not believe it unless they heard it and installed the wiring themselves.
I would upgrade the wiring to your audio room first, before trying new power cables, if possible, and then buy “used” cables and listen for differences in your set up. The improvement will go well beyond bass response...that is merely something that non-audiophiles and audiophiles alike can easily hear.