Jessica,
I'm logging your post against case 00331072.
If you have an Activboard 300 Standard with audio upgrade kit, 300 Pro, or 500 Pro, it will be in the frame on the left-hand side as you're looking at the front of the board.
These are the only models of Activboard with built-in amps, so for anything else check your audio cabling to identify.
Thank you,