Simple uBitX V3 Audio Amp Fix

Jim WB2LHP in MI <jmarco1955@...>
 

For those of you running a V3 board with the TDA2822M audio chip, here is a simple fix that should prevent the IC from being destroyed.

Insert a 15 ohm, 1/2 watt resistor in between the 470uf output cap and the (+) speaker lead. This limits the maximum DC output current of the IC. Without it, the speaker looks like a dead DC short and will stress the chip on power up and during operation. There is still more than sufficient audio power for the speaker. I am using this on my V3 with no issues. It's easy to try and doesn't involve hacking the board.

I also limit the power supply to 12 volts DC maximum. Using a common 12 volt, 3 amp switching power supply does a nice job at keeping the maximum voltage and current at bay.

Happy Holidays. Jim WB2LHP

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