If this amp manufacturer in their literature brags about the quality of the transformers they use, and how well built their power supplies are, which results in a good sounding amp, then they are clueless. Their power supply design is meant to take the outside power and convert it for the amps use. The transformer on the light pole or underground by your street is doing the same thing for your house. And if it is of poor quality, or not operating in top form, it will affect the power the transformer in your amp is converting, just like a poor power supply in an amp results in poor sound.
Look what poor power does to a computer. Why do companies install all kind of power equipment to keep their computers in top form, if it really does not matter?
Would you trust a hospital if they did not control the quality of the power running the machine keeping you or a loved one alive while they are getting well? Would you be happy if they said, it is just power and does not matter?
If "hospital grade" power cords, plugs, and power conditioners matter for the quality operation of delicate medical equipment, and matter to heavy computer users, then they must also matter for transparent, revealing audio equipment.
No rocket science explanation required.
