Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
R2 has no effect if you are driving the circuit differentially and looking at the differential output. I presumed this was the case, since you have a tail current source that greatly suppresses any common-mode gain.