Value of some items

New to the forum but thought you guys could help me with some info on some items I have. I have 2 Rowland Research amps not sure the series or how to know, 4 amps with no name only a plate with the model WL-500 and a serial number, a Polk SRT 5 speaker system, and a Win Laborties pre amp and turntable. I haven't been able to find out much info on these things especially the turntable. I have pictures but don't see where to post them here. I would greatly appreciate any help in figuring out a little more detail about these pieces and what the value may be to try and sell them.