You can assign the MIX IN signal in the TD-50 to the PHONES output only. Doing this will prevent the signal coming into the MIX IN from passing through to the Master or Direct outputs, or the USB output.
1. Press the SETUP button.
2. Press the PAGE UP button to confirm that you're on "SETUP page 1."
3. Press the F1 button (OUTPUT).
4. Press PAGE UP or DOWN to select page 2 ("OTHER OUTPUT").
5. Press F1 (MASTER).
6. Press the cursor right button to highlight "MIX IN."
7. Turn the dial counterclockwise to move the indicator to the PHONES line only.
8. Press the KIT button when you're finished. The new setting is saved automatically.