I have known of the power cord's effect on sound quality since the late 1970's. My first exposure came from a request made by our purchasing manager. He had asked me to help source a power cord for a new preamplifier we were launching.
Power cords have traditionally been added to the box containing new products. Called courtesy cables by some, throwaways by others, these power cords are included because customers rarely have extras. It is assumed by the buyer that what is supplied is adequate, if not recommended. Manufacturers treat them as afterthoughts, customers seem indifferent. Into this dynamic I was asked to help find the least expensive courtesy cable possible, one that would adequately serve the needs of the preamplifier it was intended to power.
Preamplifiers take very little power and even the thinnest gauge cables should be adequate, if not overkill. With this in mind I got samples of many gauges and put them on the test bench to make sure they worked without loss. I was not disappointed. From the smallest to largest diameter of cable no differences were evident on test equipment. Before making the decision to go with the smallest gauge, least expensive cable, I decided to make sure my foot wasn't being shot, which so often happens when I make decisions not based on listening.
I started with a 16 gauge power cable, having first rejected the 18 gauge as silly looking connected to the large preamp chassis. The sound was seemingly a bit 'thin' compared to my memory of it, but I rejected that notion out of hand. After all, the only difference was a power cable that on the test bench was overkill. Next I went thicker, to a 14 gauge, and was shocked the thinness had been reduced.
"What the hell?"
I grabbed what had been used in the past, an even heavier gauge 12, and listened again. I was floored by the improvement. Going from a large 12 gauge to a smaller 16 gauge sounded as if the music had passed through a filter that robbed its life and fullness.
This process was a revelation to me because there were no such things as aftermarket power cables at the time.
This was all new territory and much work was to follow.
