What is your experience with amp power?

My personal preference and priority is for lively sound at modest volume levels. This is more commonly achieved with tube amps than solid state.  My favorite tube types happen to be quite low in output, and I prefer amps that don’t rely on many tubes operating in parallel—fewer tubes sound more pure and clear to me.  This does mean I have to make do with lower power, but this is a minor compromise because the power I get from my amps is “sufficient” (Rolls Royce used to stay away from the numbers game by refusing to give a horsepower rating for their motors, and instead, they said its output was “sufficient”).  With my 99 db/w speakers, I get by with 6.5 watts per channel from a parallel single-ended 2a3 amp and 5.5 watts per channel from a pushpull 349 amp (my favorite amp).

First is sound quality.   If you don’t like the first watt, you won’t like more of them.   That’s not my quote, but I really liked it.

Second is synergistic.   It has to work well in my system (with my other components), not someone else’s, like the dealer’s…

Third is power.   More is always better.

Fourth is aesthetics.   It’s got to look good and have a high WAF.

Fifth is price.   I have to be able to afford it as I don’t want a new wife.

Sixth is new vs used.   I prefer new, but usually end up with well cared-for used.  (See Fifth as I get a better bang for my buck).

YMMV (your mileage may vary)…

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