Well, you can indeed use any interconnect if you don't mind the hum. Best that it be shielded.
are phono cables different from regular rca's?
to go from a step-up amp (Hagerman, FET) into the the mm input of the phono preamp, it would seem that an rca-terminated "phono" cable would be indicated; it's outputting a signal essentially the same as a mm signal from a cartridge. Is a "phono" cable intended for such low-level signals preferable to a normal rca interconnect, in this application? Are they constructed differently?