SONICA 1 - Headphone Amplifier with TPA6120

Sonica 1 is a rebirth of an older design of mine. A few years back I designed a small PCB for a headphone amplifier, based on BurrBrown (TI)TPA6120A2 chip amplifier. I made a power supply on a piece of test PCB with a toroidal transformer. The end result was quite pleasing and I have used it since then as my main source for music at home, whenever I wanted to use my headphones. You can find more information on that project here. I decided to give this project a new life and design improved PCB while using the same enclosure to house it. The old toroidal transformer is replaced with sealed one. The input capacitor for the main regulators are doubled and the potentiometer is now large ALPS. There is a fix in the control circuit. My old design was switching on the output with a second delay and switching it off the same way. The fix allows the output to switch off as soon as power is switched off, so the headphones are disconnected before the large capacitors discharge, removing any unpleasant audible effects. I ended up using EasyEDA for my design this time. More precisely the beta version of the Desktop EasyEDA Editor. Now I can do offline design as well. One thing that isn't well developed yet is the BOM generator, so I attached my own version with better sorting and manufacturer name column added.

Update on the project: PCB assembled and amplifier rebuilt. More info and photos here.

A license reminder. This project is open source, but with a license agreement (Creative Commons Attribution-NonCommercial-ShareAlike 4.0). Feel free to use my work as long as it is in line with this license. Thank you!

NOTE - When The PCB is assembled, I will add a photo. This will take some time as many components were bought on eBay from Chinese sellers and shipping takes a long time.

Change Log Rev1.3 - 07.2017

• Fixed footprint for WIMA 100nF capacitor (pin spacing was 2mm instead of 2.5mm)
• Fixed footprint for LM317/337 heatsink (mounting hole enlarged from 0.8mm to 1.4mm)
• Mains AC connector changed to 5 pin (only 3 pins mounted for safety)
• Minor improvement of plane on top layer around top N.C. pins of TPA6120A2

Rev1.2 - 05.2017

• 10 Ohm output resistors changed from 1W to MELF0204
• N.C. pins of TPA6120 connected to ground
• Ground plane added for the amplifier area
• PCB updated and PCB order placed

Rev1.1 - 05.2017

• Added ground plane for power supply area of the PCB. No schematic change

Rev1.0 - 05.2017

• Initial version of the new design