In addition to short and shielded, low capacitance is critical. This is a high impedance node which makes it ripe for hum pickup and premature rolloff / phase issues from excessive capacitance.
@nandric I can use one sut with three inputs for 3 arms that means 3 cartridges - i have one turntable with two arms and one with a single arm next to one another - they can use the SUT. I am a bit puzzled with how you think i made an incorrect choice given that amongst those recommended was an Entre over and above an FR. I did indicate that i wanted a multi input SUT, otherwise i would have just got a switch box