Amplifier advice for Wilson Sophia speakers

Why the combination of a Pass Labs amp and a Boulder preamp? Since you know about Boulder preamp, what do think of Boulder amp? What do you hear differently between a Boulder design for amplifier versus that of a Pass Labs or an Ayre? I am more interested in amplifiers for a Watt Puppy, but Sophia sounds sufficiently similar.

Because this combination gave me the best result. I would buy Boulder 1010 pre or 2010 pre but not any Boulder power amplifier. Same rule applies to Pass Labs. Nelson Pass makes power amplifier best but not preamplifiers.(as far as I know he doesn't design pre amplifiers) As long as Boulder amps concerned , only 1000 and 2000 series may drive any load below 8 ohm, 800 series will not double their output when load is below 8 ohm. On the other hand Pass Labs .5 series double their output when load drops to 4 ohm. That is very important if you deal a speaker, 4 ohm, 89 db. Wilson Sophia 2. Btw, Boulder power amps has a such a characteristic sound neither solidstate nor tube. They are built for Class AB operation. I prefer heavily biased class AB or A amplifiers. Pass is good according to my taste but not boulder.

I listen at fairly loud levels as well but also like to have great sonics at low levels for quiet listening nights after working too hard. :-) So I asked one of the audiogon pros for their advice...

Albert Porter guided me to VTL MB450s. These were an excellent choice for my room and preamp (a new Audio Research LS26) and Purist Audio Cabling. Sources include Ayre CX7e, Linn LP12 (all current updates through end of 2006).

FYI: I purchased a new pair of Wilson Audio Sophia Series 2 speakers in Oct 2006.

Happy Listening!

I heard Pass Labs X.5 series behaves like a class A at low volume. How low a volume must it be? I usually listen in the range of 70-85 db. Secondly why stop at such lowly 250W X250.5? Wouldn't an X600.5 sounds better? I heard power doesn't have to be for loudness. It also means more juice for non-woofer components to do their thing. Both Sophia and Watt Puppy are rather large speakers as well.

hmmm, I would say around 47-50 db, it will be in Class A operation.(also depends on source, cd, xrcd, Sacd, voltage of the cd player, recording.....) X250.5 will give first 35 watts in Class A mode. This is for sure, than, if you raise volume (-55 db ) it will switch to AB when it needs realy a bass slamm. If the meter of X250.5 starts shaking time to time, it means bias is not fixed, amplifier needs to switched to AB.
X600.5 will sound better with more demanding speakers from Wilson range, but not with sophias. Building a Hi-End setup is tricky thing:In this case, If I could find substantialy better amplifier, I would have bought it. (cost is no object , even my speaker cable is expensive as my Pass Amplifier)
I hope this helps.