(EN) Class D do-it-yourself stereo HiFi with Tripath TA 2040 chip

 

This is the little Hi-Fi I built. It is based on two Wondom serie boards from Sure Electronics, a company famous for manufacturing printed circuit amplifiers.

The important premise is that this project was born with two purposes: to create a Hi-Fi stereo starting from a minimum budget and to gain some experience while having fun. This means that someone more experienced in Hi-Fi than me will turn their nose up at some of my choices, probably with good reason. I am sure this project could be put together with better components, but that is not its purpose. Be lenient.

The two cards used are the AA-AB32155, capable of 2x15 Watt in class D based on the Tripath TA 2024 chip, and the AA-AB41136 bluetooth receiver.

On internet there are numerous instructions on how to modify the AA-AB32155 board to improve its sound and performance, but I found it perfect as it is so I have not made any changes.

On the front panel you have:

• the volume potentiometer
• a switch that allows you to choose between Bluetooth and line input as audio source
• a mute switch
• a Bluetooth on/off switch, so as to avoid unnecessary (albeit low) power consumption
• a blue led that indicates the Bluetooth is on
• a white led that indicates the Hi-Fi is on

Front panel

On the back panel you have:

• the C14 power socket with the on/off switch
• two pairs of binding posts to connect the speakers
• a pair of RCA coaxial inputs

Back Panel

Inside are the two boards and the power supply, which converts the mains voltage to the 12 Volts needed by the HiFi. I chose a switching power supply capable of delivering 3 Amps, which are more than enough to make the whole circuit work.

Inside the case

The power supply, 12V 3A

The case is the Galaxy model produced by MODU, with the front and rear in brushed aluminum, the sides in extruded aluminum (which also act as heat sinks) and the iron lids. The rear panel is black, while the front one is available in both black and white; I opted for the latter. The side panels also came in handy for securely fastening the power supply and pcbs to the enclosure using screws and nuts inserted into their grooves.

To screw the two boards to the wall I used an aluminum "L" profile, you can find it in DIY stores, which I cut to size and drilled. You can see the Bluetooth board on top, while the amplifier is mounted below.

The boards screwed to the side panel

For the volume I opted for an ALPS RK27 50 + 50 K stereo potentiometer, equipped with a pcb that makes the wiring easy.

The Alps potentiometer

I tested the amplifier by connecting a pair of cheap Lonpoo LP42 speakers. The sound is not bad, I can only imagine how it can improve with a couple of appropriate speakers. I want to clarify that I am not an audiophile and that the quality of the audio that this little toy spits out is more than enough for me.

I am starting a trial and listening period, on which I will try to update you in the future. I would also like to add some decals on the front panel; if I had to do it I undertake to post some photos of the result.

Have fun and thank you for reading this article.