Cables, Cables, Cables!!

[Timo]

Does your audio interface have balanced connections?

What instruments do you want to interface with it?

Most keyboards have unbalanced outputs (except the TI, incidently, which has fully balanced outputs).

For TI > audio interface, use up to six (balanced) cables on TRS jacks as needed.

For unbalanced gear, you can use unbalanced (mono) cables on TS (mono) jacks. Or, at a greater effort, you can eliminate another source of hum by manually making up pseudo-balanced cables.