Question

Is a DI box needed when using a Studio 24c to record guitar direct into Studio One 3?  I have both active & passive pick up guitars.  Not sure if it is necessary.  I plan to use Amp Sims inside the DAW.

Answer 1

No it should be fine because it accepts instrument level input. But it's weird that there's no Hi-z switch, I don't see how it accepts both line and instrument levels without it (the manual doesn't clarify this but says it works with both).

Answer 2

The Manual for the 68C says you cannot use active pickups without plugging it into a line input rather than the instrument input.  That means, unless I am incorrect, you need a DI box of some kind? 

Instrument Inputs. The 1⁄4-inch TS connectors on Channels 1 and 2 can be used with passive instruments (guitar, bass, etc.). See Input Source Button for more information.

Power User Tip: Active instruments are those that have an internal preamp or a line-level output. Active instruments should be plugged into a line input rather than into an instrument input. Plugging a line-level source into the instrument inputs not only risks damage to these inputs but also results in a very loud and often distorted audio signal