Why would you want this?  Are you concerned that your audio software is modifying the signal post-soundcard?

With tape, since the tape modifies the signal, you need to be able to monitor the tape, since that is the signal that you're committing.  But with a DAW, you monitor the soundcard's input.  The signal there is precisely the same signal that is recorded to disk.

For example, if you consider the signal chain:

1. mic >> 2. preamp >> 3. soundcard >> 4. recording software environment >> 5. hard disk

The signal at 5 is precisely the same signal that is present at 3.