In the middle you see the end of the Interface card, containing eight transistors for driving the power LEDs. On the right are the audio amps. I use three audio amps because the cabinet have one full-tone spear in front and two tweeters on the sides. I tried to make it stereo by using mixed bass in the middle and stereo treble on the sides. No success with this though, the stereo is not perceptible without lining it into a PA or something.