4 layers44.1 × 50 mm
2 layers82.5 × 39 mm
Usb dac
whatwareweb/usb-dac2USB DAC based on PCM2912A IC
- Size
- 82.5 × 39 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 28
- Nets
- 28
- Pads
- 112
- Tracks, vias
- 205, 0
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 12 Jul 2024
- Updated
- 1 Jan 2025
Overview
Usb dac is an open-source printed circuit board by whatwareweb, from the whatwareweb/usb-dac repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 2-layer board of 82.5 × 39 mm with 28 parts on 28 nets, routed with 205 tracks and 0 vias.
It is built around the PCM2912APJTR. Its parts include 14 capacitors, 9 resistors, 2 connectors, 1 IC and 1 inductor. It belongs with the audio and music boards of this library.
Main components
1README
README.mdusb-dac
USB DAC based on TI PCM2912A IC
This design is tested and working, I use it as my daily driver DAC
pcb fabrication
I ordered my pcbs from OSHpark, the project link is here for a 1-click order that is already configured and will work well https://oshpark.com/shared_projects/iy0FjLmS
performance tweaking
This DAC has been designed with good low-frequency response in mind, large output capacitors are used to ensure very low frequencies can be reproduced
To adjust high-frequency response, C4 and C5 can be decreased to allow higher-frequency sounds to make it to the output. Too high of a capacitance for either of these will lead to a muffled sound
C9 and C10 are the output capacitors, the Rubycon model listed in the BOM does very well for the price but they can be swapped out for any higher quality electrolytic capacitor with the same lead spacing. to increase LF response make these a larger value, to decrease make them a smaller value. I just used these as I had like 70 of them spare from another project
assembly
Check the assembly directory for assembly pictures
This board design is tested and working, but if you would like any help you can open a github issue and I'll try my best (no i will most likely not give you one for free, sorry)
During assembly it is very helpful to open the board view in KiCad to see the component values and the BOM
This board has been designed with easy assembly in mind, there are only 2 SMD parts which you could get assembled for you at a PCB assembly service, the rest of the parts are through-hole and very easy to solder DIY.
parts
The parts in the BOM can all be purchased at Mouser electronics (DigiKey probably has them too, I didn't check)
I just went with the cheapest option of the rated component value with a minimum voltage rating of 5v, so if you need to get components from some other supplier you can do that as well and it will probably work, just make sure to double-check the lead spacing for the capacitors, inductors, etc
bom
To export the BOM, open the schematic in Kicad, and click the BOM icon in the toolbar, from there you can copy/paste or export
Parts
28| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 1uF | Capacitor_THT:C_Rect_L7.0mm_W2.0mm_P5.00mm | C1, C8, C11, C12, C13, C14 |
| 4 | 3.3k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R5, R6, R7, R8 |
| 2 | 100pF | Capacitor_THT:C_Rect_L7.0mm_W2.0mm_P5.00mm | C4, C5 |
| 2 | 30 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 2 | 30pF | Capacitor_THT:C_Rect_L7.0mm_W2.0mm_P5.00mm | C2, C3 |
| 2 | 820uF | Capacitor_THT:CP_Radial_D8.0mm_P3.50mm | C9, C10 |
| 1 | 0.1uF | Capacitor_THT:C_Rect_L7.0mm_W2.0mm_P5.00mm | C7 |
| 1 | 1.5k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | 1M | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 1 | 1uH | Inductor_THT:L_Axial_L5.3mm_D2.2mm_P7.62mm_Horizontal_Vishay_IM-1 | L1 |
| 1 | 3.3uF | Capacitor_THT:C_Rect_L7.0mm_W2.0mm_P5.00mm | C6 |
| 1 | 5.1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R9 |
| 1 | 6 MHz | Crystal:Crystal_HC49-U_Vertical | Y1 |
| 1 | AudioJack3 | Connector_Audio:Jack_3.5mm_CUI_SJ1-3523N_Horizontal | J2 |
| 1 | PCM2912APJTR | Package_QFP:TQFP-32_7x7mm_P0.8mm | U1 |
| 1 | USB_C_Receptacle_USB2.0_14P | Connector_USB:USB_C_Receptacle_GCT_USB4105-xx-A_16P_TopMnt_Horizontal | J1 |
Questions
How big is the Usb dac PCB?
It measures 82.5 × 39 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Usb dac use?
28 parts, built around the PCM2912APJTR. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Usb dac KiCad files?
From the whatwareweb/usb-dac repository on GitHub, at the commit this page was made from: the board is usb-dac.kicad_pcb and its schematic usb-dac.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Usb dac design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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