Do I need a phono stage? noob needs help

You'll need a phono stage.

Think of it like this: That little electrical signal coming from that tiny wiggling piece of diamond sitting in the groove of a spinning vinyl record needs some help. It not only doesn't have the oomph of what comes out of your CDP or your tuner, it also needs to have its signal shifted around, put back as it was before things were changed in order to get the music onto the record in the first place. A phono preamp does both of these. And the good ones do these things better.
If you want to give it a try, get yourself an inexpensive phono pre, plug your TT into that, plug the phono pre into your Mac, and you'll see if you like it. If you do, if you get a taste and enjoy it, there'll be so darn much to discover and play with that you will be able to drive yourself completely crazy. Like many of the rest of us around here.
Have fun!

In those thrilling days of yesteryear, nearly all receivers and preamps included a built in phono stage. But since the increase of digital sources and the decrease of interest in vinyl playback, more manufacturers have eliminated the phono stage. Newer receivers, whether stereo or multi-channel are still called receivers but once the phono stage is dropped from a preamp, it is now common to refer to it as a line stage.

The phono stage performs two basic functions - additional gain (may be high for MC cartridges or low for MM or HOMC; some phono stages provide both, selectable by different inputs or a switch and single pair [L & R] of inputs) and inverse RIAA to compensate for the EQ utilized when the record was mastered. Any outboard phono stage as others suggested will do this.