help purchasing controller monitors

[yl956]

im a lil confused on purchasing a monitor controller to control the volume output of my speakers and headphones...so this is my setup i have a tlm 102 mic going into a avalon m5 mic preamp going into a lynx e44 pcie sound card.. so my next purchase would be a monitor controller...as of right now i have a pair of krk rokits 5 but will be purchasing the yamaha hs8 very soon...i also have a pair of avatone mp1 headphones&ath-m50x to check my mixes..

so my question about monitor controllers are...do certain monitor controllers colour the sound in any way? i mean do cheap quality monitor controllers add extra noise or color than expensive high quality builds?... im really just trying to get the true sound coming out my lynx e44 card without any extra effect or color to it...i just need a controller monitor for my speakers and headphones and with a mono switch and no ad/da converstion since the lynx e44 have built in ad/da converters... any recommendations?