Advice on what preamp to select.

Have an AR SP9 upgraded past a MK111. The phono is very good. So @ $1100 good value and get it upgraded further down the track if you have a good tech.

Seeing Vincent mentioned, the best Pre-Amp I own and have heard for the money is the Vincent SA-T8. Competes with or bests Pre's costing much,much more. Above your budget and line level only.

A used Audible illusions 3a would fit your needs nicely. It has 1600ohms output impedance however. What is input impedance of your monos? 

Interested and would like to see more on your SP9.  How do we proceed?

copied this from review  on the amp

The Adcom's input impedance at 1kHz was 47k ohms, and its output impedance was uniformly low—ranging from 0.02 ohms from the bass to the upper midrange and increasing slightly to 0.03 ohms at 20kHz. The gain of the GFA-565 was 27.1dB into the unbalanced inputs. I found that the three gain settings on the balanced inputs—0dB, +4dB, and +6dB—actually gave quite different readings. The +4dB setting was actually 8dB down from the 0dB, the +6dB setting was down 14dB from the 0dB. Unweighted noise was 70dB below 1W into 8 ohms
Read more at http://www.stereophile.com/content/adcom-gfa-565-monoblock-power-amplifier-measurements#o0IIiIqQ6YtF...