Can you give me the steps to remove the SMARTDAC+ GX/GP series' SD memory card?

Yes, the procedure is as follows.

1. Press MENU.
2. Tap the media eject icon.
3. On the screen for selecting the type of media, tap SD.
4. Remove the SD memory card.

For details, see “Basic Operation” in the first step guide (IM 04L51B01-02EN).