Full Range Drivers and SET's, why is a classic combo?

If they are still available, the First Watt SIT-3 does a wonderful job with a horn and at 18 watts can easily drive most any horn.  Very tube like sound and a great price

Another possibility for better bass response with still a "SET" sound is a 6W6 Push-Pull Amp that has the screen voltage properly tuned--this will give amazing response.  The 6W6 is one of the most linear tubes made and very beautiful in this configuration with full range driver.  I have come to use this as my goto system--6W6 12W P-P driving a variety of full range speakers in both horn and bass reflex cabs.  Custom transformers from ElectroPrint.  The only SET I really preferred over this was a 71A design, and although the sound was to die for it was limited to about 800mW in a single tube configuration.  As you move up the SET family (71A, 45, 2A3, 300B, 211) the sound gets progressively less clean and a little of the sound stage disappears at each level IMHO.  Not that the entire family isn't amazing--just that the lower the power, the better the sound, again IMHO.

I use Heresy IIIs and a 12wpc (depending on output tube used) Dennis Had Inspire "Firebottle" SEP (pentode) power amp and it's an astonishingly good combo...loud and clear and a sub or two makes it really work.

Cube Nenuphar’s with Bakoon 13R 😜