How big of a difference do amps make?

McPherson, Sounds like a good plan, getting a tubed amp for your Merlins. I've not heard the Thor so I can't comment further about that but it has a good reputation. I also agree with getting the 8004, it has gotten high marks as well. In fact I was thinking of getting one for backup. I have a lot of hybrid cd's and would like to hear what SACD has to offer.

FWIW I've had three 'watershed' moments in audio. My change from a SS pre to a tubed pre, my change from ss amps to tubed amps, and finding my present speakers.

Good luck. I too think you are in for a treat. :-)

Some amps make a big difference to your bank account, but do
very little to improve the sound. It is really important to pick the right amp for your speakers, so in that view, it can make a hugh difference. Dont confuse this with spending more money to get a "better" amp, because it could be a waste of money if the amps are not right for your speakers.
Hopefully you have a good dealer that has sorted through allot of combinations to find systems that work well.( a tall order, i know :)

I agree with Schubert. Tube amp with SS pre is better than SS amp with tube pre. I tried it. All tubes is the best. I have Lipinski L707 speakers and they sound great with my Linn Classik, but not nearly the same as my Cary tube set up.

The tube amp makes a huge difference, the preamp second.

I've gone back and forth from tubes to solid state many times in the past 40 years and now have both types of systems. Is one better than the other in most ways? Nope.