Just a power amp, turntable and speakers?

No, you need at least a phono preamp with a volume control.
(Very few phono preamps have volume controls, which is why most people, myself included, have a preamp with either phono boards, or a seperate phono preamp.) The phono preamp is also necessary to correct the cartridge's signal. It comes out of the cartridge with a RIAA std. phono curve signal, which needs to be corrected, or else the sound would not be a flat frequency curve.

Hope that helps, (and I am sure you will get a lot better, and more detailed explaination from others on this site.)

you could get an amp with volume control, but you will still need a phono-pre. You could do an integrated, although i do not know it any integrateds have phono stages.

unless you are mistaking a power amp for a receiver.Then your phono preamp,volume and tuner are all included.20+ years ago.

get a vintage marantz integrated amp....plug your table in.....you are home free.

I actually just got an HH Scott 436 integrated unit, but it seems like it's a little underpowered for the speakers I'm running. I was just wondering if I could employ just a Crown or Marantz power amp alone, and take the Scott out of the picture since the turntable is the only input. (I only have experience with modern integrated receivers)

Any suggestions on an appropriate power amp to pair with the Scott 436? Is there a reason to avoid a late model Crown? Or should I go with something more age appropriate?