you can stick with audio research components, but I'd still convert them all to the balanced versions. I just wonder why not SP9 balanced...?
mac seems to be another great choice of yours(that probably also has balanced inputs).
the simplier solution is to run electronic balanced line converter with balanced amp. this component is available from mac and few other pro brands. check with pro-music or audio store that may have such ones with tubes or transistors depending on your choice.