What is your experience with amp power?

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.

At the risk of oversimplification (which this is) a power amp is essentially a modulated power supply. In that context the best amps* I've heard all have large linear power supplies. As regards the ultimate power needed, all things being equal, a good big amp will beat a good small amp, but in the real world where budget constraints apply, room size, speaker choice and listening level will influence choice.

* I haven't critically listened to any tube amps above 100 wpch.

My 45w Primaluna EVO 400i and my 35w Pathos TT Anniversary sound so much better than any HP amp I've tried on my Focal Scalla Utopia. For instance, they have more bass, more punch and more control than my 333w / ch Bryston 6BSST2, which ended up in my separate HT system. By chance, an Isotek Titan power block and Nordost Valhalla power cords help a lot in terms of "punch". Primaluna is now driving my Devore O/96s and the Pathos for the Scallas is definitely a keeper

One of the best systems I’ve heard had tube, 40x2 watts going to some Acoustat speakers with a couple of small subwoofers. With the lower bass removed from the main speakers, 40 watts was more than enough power.

The "high power" tube amp that I like a lot is the Synthesis A100 (rated at 100 wpc).  That amp runs tubes of my liking-KT66 in pushpull-so it is sort of the exception to what I generally like and dislike.  If someone truly needs much more power, even though I am a tube fan, I would suggest looking at solid state because, to me, many high powered tube amps sound hard and brittle (some call it "glare").  These days, solid state does not sound harsh or "grainy" (terms commonly applied to solid state in the past); to me they sound a touch lifeless at modest listening levels and are not quite as engaging (one's mind tends to wander instead of being pulled into the music).  There is no doubt that solid state can deliver very tight and punchy bass, but overall, it is still tubes for me.  I also don't have a particular preference for tube topology--I like some pushpull amps, single ended triode amps and output transformerless amps.