Two experiences from me, the last one I can not explain. Comments welcome.
Frst & briefly: Amphion Argon 3 standmounts driven by a peachtree amp. I swapped the amp for a Krell amp of the same power. Result: tonnes of bass suddenly appears. I guess this is because the Krell amp was able to provide a lot of current when called on. I.e. it’s transient power was more.
More interestingly, due to a bizarre series of events I was able to try a second NAD C298 power amp in addition to my C298 driving KEF Reference 3 speakers (not a super tough load), this meant that I could use them as bridged mono blocks, and so went from 180W per channel to 600W, but with the same gain (this is switchable on the NADs), and no change in circuit design or parts quality.
The result of 3x more power was that everything just got more relaxed, more effortless, less shouty. I think I ended up listening louder, because it was just all so smooth. It was like my system had slipped on a smoking jacket and poured itself a brandy. Lovely. Not louder, no more base, yes a bit better stereo, but mainly just more effortless. I have no idea why this effect happens as the KEFs probably take only a couple of watts at normal listening levels.