SET the best?

Thank's Ralph. Does this apply to SETs specifically or to any low powered tube amp. The amp I'm considering is a 25W/ch 300b push-pull. That's Focal's lowest recommended rating for an amplifier to drive my speakers, but I've read advice (might have been yours) that those minimum w/ch recommendations always apply to solid state designs that increase their output as the impedance drops. That said, the amp that I have in mind is well made with pretty beefy transformers.

In analyzing your power needs it is not just a simple equation based on speaker sensitivity. You have to consider the size of your room, how loud you play it and type of music. What one person needs 100 watts for, another may only need 5 watts.

fwiw I push my 8 wpc Meishu (into 97 db AN speakers) pretty hard and always enjoy it, but I would not want less power...

You have to consider the size of your room, how loud you play it and type of music.

So true. My room is medium/large; speakers (TMM) are 87dB, min. 6.5 ohms, running full-range but are augmented by a pair of 12" self-powered subs. Power are a pair of Audio Mirror 45 Watt SET monos (Vlad says conservatively rated and able to handle peaks of 90 watts). But I do not listen at concert-level volume (average 80-85dB at seat). And the sound is glorious: clear, intimate, and great tone. I am thankful to find such a powerful, great sounding SET for my not so efficient speakers.

My speakers are 97 db and 16 ohms. I find that 30 wpc is not enough- its much easier to play the system if I have 60 watts. But the amps I use are designed to not generate any loudness cues to the human ear (unlike SETs, which rely on enhancing the 5th and 7th harmonics to get the 'dynamic' sound that SETs are known for), so I use the power without the system sounding loud. My room is 17'x 22' and is moderately lively with lots of diffusion. I do like to listen at higher levels, often reaching 100-105 db, but the system is relaxed at those levels and lacks any hint of being 'loud'.

I put 'dynamic' in quotes here and above because IME, many audiophiles when using that word are often referring to distortion of the 5th and 7th harmonics instead of actual dynamics. The way this works in an SET is the 5th and 7th harmonics don't show up until you really push the amp, which is usually on transients. So the loudness cues exist on the transients, but not in between. This is why SETs are well-known for being so 'dynamic' in a way that is out of proportion to their power. IOW its a psycho-acoustic effect.

This is why so many SET users play their systems at relatively low levels- the loudness cues created by distortion prevent them from wanting to turn it up. But if the system is designed to avoid these harmonics and has the ability to play louder, it will be very natural to do so.