I needed a stand-in for the now non-operational headphone amp on the Alesis Mixer I recently ‘resurrected’. An op-amp and two discrete transistors came to mind, but I dismissed this for my solution. The TDA2030A has been around a long time, but is still readily available, and more importantly, is only pennies more than an op-amp in price.
The schematic I present below is lifted unashamedly from the TDA2030A datasheet. There is also a PCB design in the Application Notes for the device, but I preferred to roll my own, paying cautious attention to the layout of the PCB – the GND runs in particular. With the components given, the amp output is clean and shows no signs of instability. I did all my testing on a 15-0-15 volt power-supply. Note I’ve included two 10 ohm resistors for two sets of headphones, and I’ve also brought out the amp output to a pin-header so that the amp can be used as a power-amp also.
The Eagle Schematic and PCB files are here: http://joebrown.org.uk/images/Headphone Amp/Headphone Amp.zip
Note that if only heaphones are to be connected, then a much smaller heatsink will suffice. I used the amp without any heatsink at all, and it made no complaints.
All parts are available from my handy local stockist ESR.