Best budget preamp for my entry level system?

Greetings everyone. I need some input on the selection of a pre-amplifier.

After years of making the most of and enjoying my existing budget system, I'm kicking in a few dollars to upgrade my system. I'm currently using a Marantz 2215B receiver, a Pioneer PL-550 turntable, a pair of Boston Acoustic CR-9's, an old junky JBL sub, and a bluetooth adapter to connect to my i-phone for streaming audio....

So far I have purchased the following replacement / upgrade components: Zu Audio Omen Dirty Weekend Speakers, and a Emotiva UPA-200 Amplifier.

>>> Any recommendations on a pre-amplifier? I'm definitely thinking pre-owned, and something around $300. Would want to connect my existing turntable, and a good quality CD player to it in the future. Also like to use my I-phone as a source as well through either a bluetooth adapter, or plugging in directly. I mostly listen to classic rock and rock.

Thank you, any feedback provided would be greatly appreciated!

Rene