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
The fully-working amplifier, including hand-made heatsink.
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.
The completed amp, before fitting the heatsink.
The PCB, after etching.
The TDA2030A Headphone Amp Schematic
The TDA2030A Headphone Amp PCB Foil Pattern
All parts are available from my handy local stockist ESR.
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