AC cords for Hegel H390 that do not color sound?

I enjoy the sonic attributes of my Hegel H390.

Power cords I’ve tried in the past have brought improvements over the stock cable but at the cost of brightening or darkening the amp’s tonality.

If you are able to suggest cable brands/models in the 1 - 1.5 K range that are more transparent, please do so.

Thanks!