this is from page 4-5 of the Spider Jam Pilot Guide that comes with the amp:

Output Routing for RCA Jacks

You can choose what signals are sent to the RCA jacks on the back of the unit:

Press the Tone / Settings button three times to show the additional functions.

Turn the Select knob to highlight Output Routing

Press right on the 4-way button.

To have everything come out of both Spider Jam’s on-board speakers and the RCA jacks, turn the

Select knob to select Normal

To have the Guitar come out of Spider Jam’s 12-inch speaker and everything else come out of the RCA jacks, turn the

Select knob to select Performance