I have always had a combo 2-channel & HT system. I used to listen to my 2-channel sources through my Sherwood-Newcastle P-965 pre-pro and Odyssey Audio Stratos HT3 amplifier. Adding a dedicated 2-channel preamp (first a used Conrad-Johnson PV11, recently upgraded to a used McIntosh C220), has made a large inprovement in the sonics of my 2-channel chain. Although the Sherwood is a pretty good sounding pre-pro for the money, I hear improvements in soundstage dimensions, bass extension, timbre, image definition and detail. While Yammi AVRs are a good value, I doubt they can compare to a decent dedicated 2-channel preamp. I would recommend you look for a tube-based preamp.
For a $1000, you should be able to get a used, but minty Conrad Johnson PV-11 or PV-12. I am sure there are others as well, from companies like Rogue Audio, Cary, Audio by Van Alstine, Prima Luna,Audible Illusions, Jolida, Audio Research, Belles, Manley, VTL and Quicksilver. IMHO, most any of these preamps will take your system to another level.
For a $1000, you should be able to get a used, but minty Conrad Johnson PV-11 or PV-12. I am sure there are others as well, from companies like Rogue Audio, Cary, Audio by Van Alstine, Prima Luna,Audible Illusions, Jolida, Audio Research, Belles, Manley, VTL and Quicksilver. IMHO, most any of these preamps will take your system to another level.