DIY 50W Class D Busking Amp for $10

Victor Gwee

New member
My first project was converting a 15W Artec A15C here, which I accidentally destroyed the speaker after a few months...

My second project was converting a 200W Lunchbox Acoustic here which is still up and running well. However, I desired a more efficient and lighter setup and I realised I usually don't need so much power. I also wanted to spend $10.

Most acoustic amps are class AB, which are 50-70% efficient. Class D amplifiers are about 90% efficient, which sounded like what I wanted! Hence I opted for a Class D design, reusing the cabinet from the Artec Amp for this third project. Some may have heard (pun intended) that Class D introduces distortion. However, after listening to online reviews and playing with the finished product, I couldn't tell any consistent difference between Class D and Class AB.

Let's dive into the design.

For the amplifier itself, I opted for this TPA3116D2 (50W + 50W) board on Lazada, costing only $6!

For the power supply, I went for this trusty "150W" unit for only $3.50, which allows a supply voltage from 10V to 24V (allowing you to run it off a laptop mains adaptor if you're indoors)

For the 6.5" speaker, I'd already used up my $10 budget. So I went to the neighbourhood car audio shop and asked if they had any used speakers to give away. Amazingly, I got a Rainbow KX165 coaxial speaker for free!

In theory, all these components should play nice and work together. Will update once I've assembled it together!