A lot of companies have a signature sound and Hegel definitely has one. It’s not the amount of watts as what the whole chain of electronics that makes them. I bet you haven’t used 100 watts since you bought your H390, unless you’ve really cranked up.
BTW, I have the H390 as well and am extremely happy with it. Having said that, with the H590 for sale at half price, I wonder what the used ones go for.