There is actually one substantial difference between the cable that feeds the input of a SUT and the one that comes from the output of a SUT. The difference is the impedance level at which they operate which dictates the situational needs.
Lets assume a 10Ω cartridge and a 1:20 SUT. The cable from the cartridge will be operating with a 10Ω source impedance which is so low that length and cable capacitance is typically not much of an issue. Granted the signal levels are also quite low so noise pickup can be a concern so this wire is always typically shielded. Since it is a low impedance line, the penalty of the shield is minimal. On the other side of the SUT the cable sees 4000Ω and suddenly capacitance starts to take its toll. Due to the higher impedance shielding is a must for quiet operation but the capacitance that comes along with the shielding becomes the "gotcha". This is the main reason it is wise to keep this cable as short as possible. This is particularly important when you get into the higher impedance cartridges through high ratio SUT's
dave