What affects sound quality - preamp or amplifier?

My budget unfortunately is quite limited. No more than $1500 max.

Warren get the best pre that you can afford. I always put the most $ into the control amp (the pre) which if compromised will limit all of your sources to the capabilities of the marginal pre, and if sending a compromised signal onto the amps you will never realize the quality that you paid for. Make the preamp your best piece; this is a common philosophy.

To answer your question in the spirit in which it was asked: All things being equal.... (which they never are) the pre-amp will have a more dominant affect on the sound you get. (this answer comes from my experience and reading the words of those more experienced)

When I purchased an integrated a few years ago, I got a highly recommended piece in which the pre section was weaker than the amp section. When I went to upgrade, it made the process much more difficult, I couldn't just add a better power amp when the funds were available, I had to replace the pre, then soon after get a power amp (or look at 2 front end pieces!)

The conventional wisdom is: START UPSTREAM, that is; closest to the source. Get the best pre you can and add on from there. A good pre will make a mediocre amp sound better. A bad pre will make a good amp sound worse.

What you're advising makes sense to me. So, what is a quality preamp that (must have) the 5 channel surround stereo effect which will be the primary way it is used. I'm open to suggestions about what a good combo preamp /amp would be in lieu of an a/v receiver. Thanks alot.