I am TORN between Tube power amp and SS power amp.

If the 91dB mentioned above is the sensitivity, then all that speaker needs is 1 watt to produce 91dB sound level at 1 meter. So there's no surprise that a 12 wpc amp can and will sound loud (clear is a subjective term) enough in a moderately small room. Other factors, which one could argue that are more important, are the speaker's efficiency as well as the way its impedance behaves across its frequency spectrum. Throw a piece of content with wide dynamic range and lots of transients, something like a large orchestral western classical music content, and the weaknesses become glaringly clear. Vocals, single instrumentals, and small bands like jazz trios, etc., not so much. 

Thank you very much for your informative replies. Especially to you #almarg and #kalali. You are very helpful guys! I really appreciate your feedback.

Cheers!🙂

I run both a solid state phono stage generally viewed as one of the best ever made, and a tube phono stage (CJ Premier 15).  Both give satisfaction.

Suggest that you seek out a good sounding phono stage and not worry about what the internals are.

   Hi Rodulfo, I have a pair of JBL 4312A’s on Sound Anchor stands . They are currently in the closet as I went to low power tubes . Your speakers need 100 plus wpc tube or 200 wpc SS . I’ve run these along with  my long gone Century 100’s using Dynaco MKIII’s ( 60 wpc ) , ASL 30 wpc ( El 34’s) Sansui 9090db, Bryston 4BSST, Yamaha RX-V, Modwright KWI-200. So with tubes , 30 wpc was too little and 60 was just starting to cut it . The Yamaha was 105 wpc ( but home theater stuff ) so not good. The Modwright had good control , but was dry . The Bryston was great ( so maybe the Hafler would be nice) . I contacted Quicksilver and they recommended their 120 wpc amps . Most people underestimate how much power the JBL’s need . Also too little power leads to clipping damage . I would go with SS for simplicity, but it might be too dry for your taste. This is a good speaker for a tube pre and a SS amp , or a big tube amp. I’m actually considering the Latino 120 wpc Monos . FWIT many people bi-amp the big JBL’s with tubes on top and SS for the woofers ( sometimes class D). But that’s a whole different beast , but due to the large power requirements. Many of us are willing to deal with the hassle of tubes because the result can be stunning with vintage JBL’s . BTW I also have Klipsch Heresys, but prefer the JBL’s . Happy Hunting, Mike. 

  Also , I have a Had Inspire on right now . At 12 WPC , don’t even try to run the JBL’s . That’s why I have Heresys and KG 1.5’s to supplement  my Zu’s .