How will a pre amp help me with sound in a home stero

I'm curious why you would want to do this. As receivers go, this is pretty decent.

A pre-amp is just the control part. A receiver is an amp, pre-amp and tuner all built into one box. What kind and model is the pre-amp?

To use the pre-amp, since the pre-amp as no amp you would have to run it into a separate amp or back into the receiver. For example if the pre-amp has optical inputs and that receiver won't have any opticals inputs, HDMI and etc.

Most recievers don't have a turntable input. That would be the only reason to add a preamp with one IMHO.
Dave

It's an old receiver made back around late 70s~early80s so it has a turntable input.

sorry, dbl post.