DIY Music Gear: SK3875 Amplifier & Speaker Tips

If you're up for some DIY music gear, consider trying out the SK3875 amplifier board. You can easily find pre-made boards online.

This is an amplifier board. 

Once you've got the board sorted, finding the other components is a breeze.

You'll also need a chassis and various small parts. The maximum internal dimensions for the chassis are 342mm depth, 92mm height, and 218mm width. Mounting holes have an 8mm diameter, suitable for transformers with a maximum diameter of below 120mm. The heat dissipation holes measure 187mm*30mm, with a distance of 163mm to the inner panel.

For power, a 160W toroidal transformer with dual 26V and dual 15V outputs is recommended. The 15V output powers the preamp.

Here's a semi-finished diagram for the DIY project.

And here's the completed assembly.

For speakers, consider using a simple maze-type enclosure with 4-inch full-range drivers. Once assembled, you can solder the speaker cables yourself.

As for the audio source, you can opt for a ready-made player like the one shown below.

Once you've got everything ready, it's time to wire it up and give it a test listen.

Generally, after a few days of testing, you should reach a satisfactory level. However, you might encounter minor issues with the amplifier, such as noticing some background noise when turning up the volume without music playing. In that case, a quick fix involves opening it up and adding a ground wire. After this tweak, you should notice a significant improvement. Even when the volume is turned up high, you'll only hear a slight bit of noise if you place your ear close to the speaker; at a little distance, it should be barely audible.

If you find the low frequencies lacking, consider adding a two-way crossover and upgrading two op-amps, swapping out the 5532dd for the 2132. This upgrade applies to both the amplifier preamp and the audio source.