Audio Amplifier

Project Overview

We created a PCB to allow users to change the volume of their audio signals before it goes to their speaker, via 3.5mm headphone jacks. You can also optionally put your signal through custom digital filters to change how it sounds!

Block Diagram

We used this high-level block diagram to inform the design of our PCB, with some small changes:

Instead of at the end, we place the amplifier at the start, allowing us to amplify the initial, non-offset signal
We had to add DC offset and unoffset blocks before the signal went to the microcontroller to center it around 1.65V, stopping information loss on digital conversion
We had to also create a a block to generate -3.3V from 3.3V, as -3.3 is necessary to power Vss of all our amplifiers

Schematic

DAC

Power Regulator

5V to 3V3 converter

DC Offset Block

Analog/Digital Toggle Mux

Amplifier

Output Buffer

Layout

USB-C

5V Regulator

5V Step-Down

Microcontroller

LED Indicator

Audio DAC

Slide Switch

Potentiometer

Audio Amplifiers

Headphone Jack In/Out

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