Miniamp

Miniamp

A portable, battery powered Hi-Fi DAC and headphone amplifier.

Shortcuts

• Features
• What is it?
• Resources
• Assembly
• Bill Of Materials
• Photos

Miniamp Zine

Features

• Independent USB-C Ports
  • Top Mounted Data Only USB-C
  • Side Mounted Power Only USB-C
• Variable Size Audio Outputs
  • 1/4"
  • 3.5mm
• 5 Physical Media Control Buttons
• Toggleable Power Switch
• 2 Integrated 18650 Batteries
  • Avoids Discharging Connected Device (e.g., Mobile Phone, Laptop)
• Small Form Factor

What is it?

Miniamp is a portable, battery powered DAC and headphone amp designed for phones, portable devices, or for desk deployments. The Miniamp features a Hifi DAC chip capable of producing 24bit 44.1kHz outputs at 2.1Vrms, with adequite power for majority of headphones. It utilizes a Silicon Labs CP2615-A02-GM USB to I2S chip, a Cirrus Logic WM8524CGEDT DAC, and an Analog Devices MAX97220AETE+T headphone amplifier. It also has a battery charging and protection circuit to handle charing, protection, and output regulation to the ICs using 2 18650 batteries in a 1s2p configuration. This setup removes power draw from the data streaming device and offloads it to the batteries, with a passthrough power circuit to power all devices externally with a long battery life.

I created this to have an easy device to bring around with me at school so I can use my wired headphones and control them without the need to open my phone for controls or worry about my phone dying which was really nice. It should work well and do exactly that since I love the apple dongle, but its just super small, feels like its gonna break, and just kinda basic without any controls.

Resources

CAD Link: https://cad.onshape.com/documents/a14a9a55c78bf32f82e1c97a/w/0351478092a46614c60a771f/e/1fa4c67b30b50298fb86e419?renderMode=0&uiState=6a336e0a197a1dd98d81aa96

CAD Files: HERE

ECAD Files: HERE

Production Files: HERE

Assembly

You will need:

• PCB (PCBA with ICs attached if you do not have a way to solder smd parts without legs, the assumed method of this assembly guide)
• Rest of ICS needed
• Required Heatset Inserts
• All printed parts
• Soldering iron
• Solder
• Matching screwdriver to screw set (allen key in provided kit)
• Small pair of tweasers

1. Gather all resources, print all case parts, and have a clean open workspace
2. Carefully solder all components not installed with PCBA according to the schematics and ECAD files (most resistors, caps, and all THT parts)
3. With the PCB assembled now, to start assembling the case you want to heat your soldering iron to about 225°C and carefully insert the M3 heatset inserts into the standoffs on the top case part.
4. Now that both the case is assembled and ready, and the PCB is ready, test the PCB outside of its case to ensure it will work without issue. If there is an error, seek help or investigate to make sure all components are placed correctly.
5. Insert the PCB into the top case, slide on the TPU band, and screw in the bottom case using the 4 M3 bolts
6. Enjoy!

Bill Of Materials

BOM: HERE

PCBA BOM: HERE

Both can be found in files, normal BOM here and the PCBA BOM here

Photos

Miniamp Main PCB Schematic

Miniamp Power PCB Schematic

Miniamp Case Front

Miniamp Case Back

Miniamp Case Inside

PCB All Layers

PCB F.Cu Layer

PCB In1.Cu Layer

PCB In2.Cu Layer

PCB In3.Cu Layer

PCB In4.Cu Layer

PCB B.Cu Layer

Top of PCB

Bottom of PCB

Render of PCB

Credits

This project uses:

• KiCad
• Figma
• Hack Club Fallout