First Watt F7 driving Wilso Sophia II's?

The F7 is a fine amp, it’s going to be a bit of a gamble, depending how quite you listen, it’s only 20w into 8ohm and still only 30w into 4ohm, I think you’ll reach it’s limit very early before you get to medium/loud level.

The Sofia 2’s are 88db not an evil load, but not easy either.
The speaker’s impedance drops to a minimum value of 3.26 ohms at 220Hz. This is upper bass where a lot of power is needed.
https://www.stereophile.com/images/archivesart/Sopfig1.jpg

Think they'd be happier with the Conrad Johnson Premier 12 Monoblocks 140w version you were talking about in other posts

Cheers George

georgehifi. You are not incorrect. In fact my Wilsons liked the solid state Premier 350 from CJ best. It could run them at volume 4-15 and be completely in control, meaning the sound was full and rich where in comparison the Premier 12’s tube amps need about a volume of 35 (running ET-5 or Premier 16 LS2 pre’s from CJ). It’s not high volumes I’m looking for but detail at low volumes, bass at the same, no slam needed. 
This said I’m interested in Pass Labs SS equipment.  I also have Revel speakers and Klipsch Forte’ speakers at my access and this may be for a different room. I’m just investigating and educating. 

For what it's worth, I run my Sophias with a pair of VTL MB125s or a pair of Quicksilver M120s with the KT150 tube upgrade with great effect but just love to drag out my Pass Labs XA30.5 which I just can't bring myself to sell although heavy and bulky and doesn't physically fit in my system just sounds marvellous and seems to my ears as powerful as the tube amps.

tooblue667 It was worth a thought. My CJ tube amp is an ART 150, using KT150's and 6922's hooked up to my ET5 or Premier 16LS2 or Premier 17LS and then the Sophia II's. The ART with the ET5 is close to Nirvana, the ART 150 reminds me of my Premier 350 with tubes and less fatigue. 
On reading your XA30.5 note, I exchanged email with Nelson Pass who recommend I look at the XA25. I did and I purchased it for use. He also said I would have no problems pairing it with my CJ pre. I have no problems finding a speaker to work with it if need be but I don't anticipate that.