Tag: usb audio interface

Build this Simple but amazing USB Audio interface for only $5

In case you want to connect your audio mixer or electronic piano or any other line level audio equipments to your computer or laptop for recording, here is a simple USB audio interface circuit that does the job. It is based of PCM29XX IC from TI. This is used in many analog audio mixers with usb interface such as the Behringer Xenyx USB mixer series.

About USB audio interface circuit

This circuit is USB powered. The IC has 16bit delta sigma ADC and DAC and capable of up to 48kHz sampling rate. it has stereo line level input and outputs.The crystal needed is 12MHz.

 

Quick PCB design

Here is a simple PCB layout that I designed using kicad software.

3D Render

simple usb audio interface PCB design
simple usb audio interface PCB design

Want to have a copy of the Kicad design? Just like my facebook page and send me a message. thanks for visiting… 🙂

Prototype

Since I needed this circuit for my recording may piano and guitar covers, I built my own using universal PCB. This is what I used on my guitar and piano covers on my youtube channel here. 

At first time try, I am having problem with it. Windows shows an error message “Device not recognized” when I plug this to my Laptop’s USB port. Upon hours of troubleshooting, I found out that C13 and C14 is causing this issue. These are the capacitors connected to crystal oscillator. When I tried to removed these capacitors, the issue now gone. I tried to lower the value from 22pf to 15pf but it didn’t solve the issue. I also tried 5pf but same thing happens. For this prototype I just removed C13 and C14. Maybe because there is parasitic capacitance on the board that I used.

There’s no need for drivers, it installs automatically when you plug it in. It has 16bit ADC/DAC with up to 48kHz sampling which is good enough for recording. 16bit/48kHz might not sound great but it is actually good. This chip is used by Behringer on some of their Xenyx USB mixer and also on their cheap usb audio interface. The audio quality is not the best but it is better than those cheap USB sound card on the market. This is good enough for recording for you youtube content. 

Video

Here is the actual video of my prototype in action.

Please subscribe to our YouTube Channel. 🙂

USB audio interface Parts list

RefValuePart
C11u16V electrolytic capacitor
C20.1uceramic capacitor
C34.7u16V electrolytic capacitor
C44.7u16V electrolytic capacitor
C51u16V electrolytic capacitor
C61u16V electrolytic capacitor
C71u16V electrolytic capacitor
C81u16V electrolytic capacitor
C91u16V electrolytic capacitor
C101u16V electrolytic capacitor
C114.7u16V electrolytic capacitor
C124.7u16V electrolytic capacitor
C1322pceramic capacitor
C1422pceramic capacitor
D1LED:LED
J1USB_B:USB connector
J2Input3pin JST connector
J3output3pin JST connector
R12.2 ohmsResistor SMD or 1/4W or 1/8W
R21MResistor SMD or 1/4W or 1/8W
R31MResistor SMD or 1/4W or 1/8W
R41.5kResistor SMD or 1/4W or 1/8W
R522 ohmsResistor SMD or 1/4W or 1/8W
R622 ohmsResistor SMD or 1/4W or 1/8W
R71MResistor SMD or 1/4W or 1/8W
R81MResistor SMD or 1/4W or 1/8W
R91MResistor SMD or 1/4W or 1/8W
R10220 ohmsResistor SMD or 1/4W or 1/8W
U1PCM2902CUSB interface IC
X1CRYSTAL12MHz Crystal

The parts list does not include input and output connectors, you may opt to use RCA or phone jack connector.

I am planning to build an improve version of this device and sell it online so stay tuned! Subscribe to my youtube channel and facebook page to keep you updated! 🙂