Total newbie question here about completing a system

Hello all: Forgive the novice nature of this, but I'm trying to help my son build out a system and I'm a bit lost. Here's what we have so far: Adcom GFA 5500 amp, Audio Research LS2 preamp, Klipsch RP-160M reference premiere bookshelf speakers (new), an old Yamaha turntable, plus a tuner and CD player that we're not certain we'll use. We seem to be missing an equalizer, correct? Also, I should note my son plans on using mostly digital (Pandora, etc.), plus some wax. Please advise on what we need to round this out. The digital feed needs to be converted, correct? Again, so sorry for the basic questions, but most of these components are inherited and I don't have enough understanding of putting this together. All wit and wisdom welcome.