Take a serious look at the Puritan power conditioners, 136 and 156. Less expensive than the big boys and actually more effective. If I had to apportion money, I'd put it there before trying power cords. BTW, the Puritan PCs are also very good and don't break the bank. But the 156 is transformative: check out several threads about it here.
Help selecting a power cord.
All my gear has the factory supplied power cords I’m ready to try 1 aftermarket power cable as a test. So what brand power cable should it be and what device gets it first? Tube pre? Tube main? D/A? CD transport? Roon Nucleus? Subs? GE Trefs?? Turntable? Oppo 103? Which piece of my gear should be most affected by the improved power cord?? I look forward to the responses and will likely choose the cord that has the most recommendations.