Amp/Preamp combo for Wilson Sophia 3's

Bo1972, the JBLs are capable of very good depth. The problem is not the crossover but how the amplifier drives the speaker. Higher efficiency speakers also have a lot of back EMF, which can mess with amplifiers that employ a lot of negative feedback and also have a low output impedance. The speaker does not need a lot of power; but the power that it does get has to have some finesse.

I see. Thanks for the info!

bo1972, if boulder is so lacking, what SS amps are suitable for your listening standards? (i found the pass XA series lacking control, though they did sound pretty good).

I would choose for the X series and not for the XA series. I will do personal a next upgrade to the X600.5 as well. I prefer drive and speed as well. The difference between Boulder and Pass labs is more than only the sound. The Pass Labs gives a different focus on the different instruments. You hear more easy the difference in the sound of all these instruments. With the boulder it is extremly well controlled, but you miss the different coulor of instruments. Sound realism is a very important part in the world of highend.

then we'll disagree. i've owned both xa's and boulder, and prefer the boulder considerably. i understand why you like the pass. i just don't think you've heard the boulder in optimal conditions; the pass can cover sins, the boulder does not, if that makes sense...the boulder also needs to be warm to sound best, whereas the XA series comes to life quickly.