How do I overdub on the TP-7?

The TP-7 does not have a traditional overdub function where new audio is layered on top of existing recordings. However, you can achieve a similar result using the mixdown feature with a TX-6 mixer.

Mixdown with TX-6

The manual describes a mixdown workflow that lets you combine multiple tracks. This requires a TX-6 connected to the TP-7, where individual recorded tracks can be routed and mixed together into a new stereo file.

Alternative approach: multitrack recording

The TP-7 supports multitrack recording, which lets you capture separate takes or sources as individual tracks. You can then play these back together and adjust their levels, effectively building up a layered recording without destructively overdubbing onto a single file.

Memo recording

For quick layering ideas, the memo recording feature lets you capture short takes independently, keeping each pass separate so nothing is overwritten.

If true overdub (recording onto the same file while hearing playback) is a core part of your workflow, the TP-7 is not designed for that use case. The multitrack and mixdown approaches are the closest the device offers.