Pass XA100.8 or Sim W7 Monos?

Contact Quintessence Audio in Skokie Il. as they may carry both makes.
I am not associated with the busines.

If you go with the W-7, I suspect you would get better results with one amp operating in stereo mode than with two of them operating in bridged mode.

You'll note that in bridged mode the W-7 has a maximum power rating only for an 8 ohm load (600 watts), and no rating for a 4 ohm load. That is often the case for bridgeable amps operated in bridged mode, because in that mode the amp "sees" a load impedance equal to the speaker impedance divided by two. So the nominal 5 ohm impedance of your speakers would be seen as a very challenging 2.5 ohms, and undoubtedly the actual impedance is significantly lower than 5 ohms at some frequencies.

Also, based on its 150W/300W ratings in stereo mode for 8 ohm/4 ohm loads, the W-7 should be capable of around 240 watts into 5 ohms in stereo mode. That is significantly more than the XA100.8 is capable of, at least on paper, and is within 1 db of the upper limit of the 50W to 300W range of amplification recommended by Dali for your speakers.

If you do want to invest in a pair of W-7's, it would most likely be better to biamp them, in a vertical biamp configuration.

Regards,
-- Al

The Dali's are themselves perhaps a little on the polite side. The A/B Pass Labs amps may be more appropriate for your system and taste. An X150.8 would be less expensive, more powerful, still have fairly high bias, and might be just what you're looking for. The smoothness of the XA amps is wonderful for very revealing speakers.