Indeed, high efficiency and high impedance speakers are common factors when you read/hear someone is happy with a SET amp. Another factor is the SET should be driven "well below" its rated power, which is of course undefined how low is low enough.
I'm in the process of building an active system with SETs for treble and midrange and class-D for midbass and subwoofers. It's said power required below and above 350Hz is about the same, so by crossing around there (or higher) you relieve the SET from carrying half the load. If you further divide the upper range into two, then each amp will carry 1/4th of the load.
I have my eyes on Yamamoto's A-08S (45 SET), and while the speaker driver options aren't super wide, there seems to be enough. I guess demand pulls for drivers where high efficiency and impedance aren't as big a deal, the manufacturers follow suit. It is being a fun journey!
I'm in the process of building an active system with SETs for treble and midrange and class-D for midbass and subwoofers. It's said power required below and above 350Hz is about the same, so by crossing around there (or higher) you relieve the SET from carrying half the load. If you further divide the upper range into two, then each amp will carry 1/4th of the load.
I have my eyes on Yamamoto's A-08S (45 SET), and while the speaker driver options aren't super wide, there seems to be enough. I guess demand pulls for drivers where high efficiency and impedance aren't as big a deal, the manufacturers follow suit. It is being a fun journey!