It depends on the model and how you plan to route signals:

Submarine (2-string) – Works with a single input for combined output, or two inputs if you split its two adjacent strings independently.

SubPro – Provides up to four separate outputs. For full flexibility, an interface with at least four inputs is ideal, though you can also run mono or stereo with fewer.

SubSix – Provides six fully independent outputs, one per string. To capture each string on its own track, your interface needs six instrument-level (Hi-Z) inputs. If you have fewer, you’ll need a mixer or DI setup to manage or combine signals before recording.

You may also want to include the output from your guitar’s regular pickups alongside the Submarine signals. Many players find unique sounds by blending the two – using the Submarine Pickups to augment the existing tone with extra layers, processing, or separation.

In short: more inputs mean more routing options, but all Submarine Pickups can still be used effectively even with a simple 2-in / 2-out interface.