Ultra is (digital) preamp for active 4 way dipoles (full range drivers)

[Poultrygeist]

I'm also an open baffle devotee except I run full range drivers with nothing in the signal path between single ended tube amp and drivers. I use a separate amp for the LF. I've tried DSP and active crossovers but they add their own sonic signature and detract from the SET magic. Currently using a Wiim Pro+ into a SU-9 DAC.

 

[Poultrygeist]

In the garage I use a WiiM Pro streaming to a Schiit MB DAC. A SET amp drives the Lii Audio F-15 OB's while a plate amp drives their Eminence Alpha bass woofers. The box speakers are Swan HiVi kit speakers from Amazon powered by a Fosi ZA3 and it shares the WiiM stream.

 

[Poultrygeist]

My favorite OBs so far are the 12" Zenith 49CZ alnico's from 1957 with front firing compression horns and rear firing Realistic super tweeters wired out of phase over 15" Eminence Alphas H-frames. A Decware SET amp drives the Zenith and tweeters while plate amps power the bass woofers. Low bass provided by a pair of Bucket Subs. https://www.transcendentsound.com/bucket-sub.html