Dual 3A DC-DC Voltage Regulated Power Supply LM317 LM337 BD139 BD140 TIP35C TIP36C

Preface

Fig.1 – The dual 3A DC-DC voltage regulated Power Supply

Fig.1 – The dual 3A DC-DC voltage regulated PSU

Initially I built this PCB because I was fed up to hear the annoying low frequency noise from the speakers of an old amplifier. The issue came from the power supply that clearly wasn’t very good. The residual 50Hz signal from the AC line, technically called ripple, was so high that it generated an awful fixed background sound. By installing this PCB, after the existing PSU, I solved my issue.

Later, I decided to use the PCB as a general power supply to test my projects. It has always worked perfectly even if setting the voltage output by trimmers was not very comfortable. For that reason, if you are thinking of building it for that purpose, I suggest to substitute the trimmers with potentiometers by connecting them with wires to the board or, better, redraw the whole PCB mask.
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Amazingly Small and High Performance Audio Power Amplifier LM3886

Preface

Fig.1 - The amazingly small and high performance audio power amplifier with LM3886

Fig.1 – The audio power amplifier with LM3886

By using the LM3886 it is possible to build a very small PCB but with the performance of the more complex and expensive commercial power audio amplifiers. Of course I’m not comparing this amplifier with some super ones available in the market, but you’ll remain amazingly surprised listening to how good it sounds.

The basic configuration suggested by the LM3886‘s data sheet works well already but it is possible to change something to make it sound better. For instance adding a few extra components to filter the signals more carefully, or, since a handful of components are necessary, it might be worth spending a little more money to buy some high quality ones.

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