Cool Cap Engineer

Engineering by an anime nerd

Mini Projects: 15 Watt Audio Amp Experiment

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A couple weeks ago, I mentioned that I was learning how to build audio amps and I tried building one using Sparkfun’s STA540 audio amp kit. Well, I tried to design the PCB for my modified version of Sparkfun’s audio amp kit, but I ran into a very….large problem. In order for me to make sure the STA540 properly drives two speakers at 25 Watts, I needed a multiwatt heatsink. However, the heatsink takes up 1/3 of the PCB! Not to mention it will be a pain fitting it inside a box since the heatsink is also very tall! In otherwords, I needed to find something else.

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Then I heard about the TPA3122, a 15 watt stereo audio amp.  Although it can only drive 10 watts less than the STA540, the space it saves more than makes up for it. After building the circuit, I ran into latching issues, or when the ic stops working due to voltage spikes on the dc bus. At first, I thought adding more bulk capacitance would help, but it had no effect. After asking around, one person suggested to rewire the circuit to be much more orgainized. Not only did I rebuild my circuit on the breadboard, but I place .1uF decoupling capacitors as close to the IC as possible. Afterwards, the amplifier worked marvelously! I even recorded a video of the amplifier in action.

Suffice to say, I will consider using the TPA3122 for my next audio project. Well, that’s all from me today! If you have any suggestions, comments, or concerns, please feel free to use the comments below. See you guys again next week!

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