Will adding a preamp dramatically change my sound?

Generally the problem with CDP-to-amp direct is the use of digital volume control, which can greatly compromise the sound. However, since your Cary is providing analog volume control and Cary generally uses high quality parts, I doubt you'll gain much, if anything, by adding a pre.

As you spend more and more, both analog and digital volume controls can, and usually do, get better. Still, if this is going to be your only source and there's a good match with your Spectron (you'd expect that from Cary) then you're probably in great shape.

Cutting out a set of ICs is almost always a good thing. In fact, you'll probably gain more by upgrading your ICs and PCs than adding a pre.

Anyway, there's no harm in trying a pre-amp, but don't buy without doing and A-B comparison.

Dave

you also want to consider the output impedance of your player in relationship to the amp. A preamp could lower the impedance making it easier for the amp to drive the signal.

a preamp may color the sound, creating a "flavor" you may or may not prefer. it may be worth your time to listen to a feww preamps.