Since ATCs are intended for use with a balanced source, it would be a good idea for that source to support the balanced line standard. In this way you can run longer interconnect cables and the artifacts of those cables will be minimized- meaning that you don't have to use expensive cables to make it work really well.
The tricky bit is the input impedance. Most tube preamps won't be happy about the 10K per side (our preamps drive that just fine FWIW). So check with the preamp manufacturer to see if this is an issue. BTW, if the preamp supports the balanced standard (also known as AES48) then the input impedance is not an issue for the preamp.