SET amp for high efficiency horn speaker

Also take a look at the hand built Deja Vu Audio SET and PP amps in both 300B and 2A3/45 configuration, which come up on Audigon occasionally. Those built around vintage Chicago and Acrosound output transformers are quite amazing.

go for KR Audio amplifiers. The most quiet amplifiers and SET with bass....

What about SET like Yamamoto or one from Komruo?

yamamoto 45,wavac md300b, jeff kornef 45 SET,art px25,cyrus brenneman cavalier,FI 2a3 mono blocks. Depending on your loudspeakers design these should work well I used them on my hi-eff horn riggs. Still some horns can be a bit harder to drive any info on your horns would help with suggestions. Mine are also 109 db 1 watt 8 ohms so easy load for SET which they are designed to use.

Which loudspeakers are you using? I ask this because I own 3 pairs of highly sensitive speakers but lower than 110 DB. The reason I ask is that the smallest amp I use with my most efficient speakers (104 DB) is a Mac with 50 wpc. I use vintage amps with "36 watts" per sidewith Vintage JBLs that are 102 DB/W/M. -In quotes because this figure has been questioned. In any event a highly sensitive speaker need not be driven by a low power SET. The opposite is true you cant drive low sensitivty speaker with a low output SET. The extra head room is surprisingly very compatible with high efficiency speakers and yields a richer tone and body to the sound. Flea power is said to be purer but I think it just sounds thin. SET amps with a single power tube are not all low power. Some give you that rich sound with the minimalistic signal pathway, just pick amongst the suggetions. If you like 300Bs you can get them in a paralel push pull circuit which delivers 18wpc. In any event be sure the trannies are very substantial your power supply is critical.