I'm having a really hard time with: "Power cable reduced my soundstage"...

A soundstage is a mental construction of the listener based on the tonal accuracy of the equipment. If the soundstage shrinks it means the component may not be as tonally accurate as it should be. Power cables are capable of affecting the tonal balance of an audio component. That’s how they could shrink a soundstage.

Super good question. AFAIK, the best a power cable can do is block noise, and transmit power.


Too good a cable, and it transmits noise and power. Based on this, here is my thinking on an affordable, effective middle ground:

https://inatinear.blogspot.com/2019/04/power-management-for-frugal-audiophiles.html

Tone and soundstage are two very separate performance characteristics IME.

The academic studies of psychoacoustics better explains the difference your friend claims to hear - more so than any quasi-technical explanations you’ll find littered throughout the web and this forum.

The only ways a power cord might affect the sound is if it either, a) restricts current (increases resistance) to the point that it limits the amplifier beyond its maximum current draw capability, or b) its shielding is different, thereby causing an increase or decrease in the total EMI of the system. These two scenarios are both uncommon.

What is most likely is that your friend expected to hear a difference which affected his/her brain chemistry (altered mood) which led to a real perception (not necessarily reality) of difference. That’s about as close as a component can get to creating "magic." Remember that all magic is an illusion.

The same phenomenon occurs when one listens to their system while fatigued, or following a stressful day.