Table of Contents

Headphones and Mixer section

Schematic Overview:Headphones and Mixer

VoltageControlledAmplifier Audio

IoBoard Audio (Mix out and Headphones)

This section is relatively simple. It taxes the incoming signal on the Mix In jack, and combines it with the x0xb0x signal. Then it is sent to Mix Out Jack. It is also sent to the headphone section, which is the LA4140, and support circutry.

The Mixer

The input from the VoltageControlledAmplifier goes through a Capacitor and Mixing Resistor, so that it can be mixed in with the audio from Mix In. Note that the Mix In Audio has twice the resistance as the x0xb0x audio.

(blah blah transistors, blah blah. Need more info. WorkOnMe)

The Headphone Amplifier

The Headphone Amplifier uses a LM4140. It's support circuitry is practically right out of the datasheet, with a few exceptions. (WorkOnMe)