Hi John,
when you plug something in the Line input, it disconnects the Speaker input from the speakersim (the load is still attached to your amp).
On the Torpedo Live there is no easy way to have both input connected and switch from one to the other. You have to unplug the 1/4" from the Line input to get the Speaker Input back.
On the VB-101 Torpedo Studio you can select the input from the Torpedo Remote or on the unit itself (selection by relay).