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!


Other really good lower cost values:  older Dyna PAS 3/3x tube units; Counterpoint SA-1000 tube unit.
Johnkent3 does the Yamaha CX-630 use traditional relays or solid state switches for input selection? I’ve got a NAD 1600 preamp/ tuner that has solid state switches, one of which had become defective and causing distortion. I’ve liked the quality that Yamaha stands for, and might replace the NAD 1600 with one of these. 
Well, regarding the USP-1 vs. PT-100 comparison, given the information supplied by auxinput, between these two choices I would be inclined to purchase the USP-1 due to design approach/build quality. I agree that 10 years does not represent 'old' for an amplifier. Provided the condition of the USP-1 under consideration was in good condition. 

There are other used preamps that could also be considered. Makes from NAD, Rotel, Jolida, Vincent, B&K, Hafler to name a few. I would look for a 2-channel pre.

Does your receiver have pre outs? If so use it as a pre and save additional funds for a more substantial upgrade if so desired.

Check out the Parasound Zpre3 add here on audiogon. Might just be the ticket.