SET the best?

Hi Ralph,
I'm going to acknowledge, before I even ask, that this question is likely an example wrongful thinking.

Many people use tubes with speakers that were probably not designed with tubes in mind - in my case JM Lab Mini Utopias. My question is: Can a modification be done, perhaps to the crossover, that would result in the amp seeing a friendlier impedance curve?

For clarity, I'm asking about speaker mods only.

Phaelon, SETs are usually not very powerful. A big one is 15 watts, maybe 20. If you really want to hear what they do, the speaker has to be efficient enough that you never bring the amp anywhere near full power.

At full power, the THD is often about 10%! At low power levels, the distortion might be unmeasurable, and what of it there is will usually be lower orders (2nd, 3rd and 4th). At high power the high orders become involved- that is the range of the amp that tells you not to turn the volume up any higher- it *sounds* loud due to to the presence of the 5th and 7th harmonics, which tell the brain how loud the sound is.

So the efficiency of the speaker is paramount and no matter what anyone tells you, to really hear what SETs do you need high efficiency: 97-98 at a minimum if your amp makes 15-20 watts. A 45-based amp needs a speaker that is more like 107 (if you really want to hear what it does anyway). This power limitation is one reason why I don't use SETs. The bigger you make them, the less bandwidth and detail.

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.