Just a power amp, turntable and speakers?

As has been said, you need a volume control in the circuit, which is what a preamp does. Otherwise it would simply play at full volume all the time. Plus you must have a phono preamp, either built in to the system preamp, or a separate unit. The phono signal is very low output, plus it is equalized with an RIAA curve, and sounds horrible without the proper re-equalization.
Does your Scott integrated have pre-amp output jacks on the back? If it doesnt, you cant add a separate power amp to it.

Yes, the Scott unit does have a pre-out.

Are you sure that it is pre-amp out, and not just a tape out, which will not have volume control.

Damn, you're right. It's just a tape out. I was thinking it had a true pre-out because that's what the seller told me. Not a big deal, I didn't pay much for it.

I'm going to get something new I think. I'll read up a bit on this site first, for sure.