I picked up a used Jolida Fusion preamp last summer for about $700 and put it in my bedroom system (Integra 80.3 AVP and Wyred4Sound ST-1000 MK2 amp) and it provided an improvement over the 2 channel audio of the Integra, not a dramatic one though. The Fusion has a home theater bypass function so you should be able to switch it between your receiver for 2 channel and home theater.
In my main system I have a Modwright LS100 for 2 channel and the sound quality is dramatically better than my Marantz AV7704 AVP.
Unless you score a nice used preamp at a below market price you're probably not going to realize much of an improvement if your budget is under $500.
In my main system I have a Modwright LS100 for 2 channel and the sound quality is dramatically better than my Marantz AV7704 AVP.
Unless you score a nice used preamp at a below market price you're probably not going to realize much of an improvement if your budget is under $500.