I’m thinking to create a first gift for my newborn (ooopsss… he is not yet here, just about to). A small MP3 Player with tiny amplifier to drive a small speaker should be a nice idea. I will introduce him to music as early as I can. So this could be the right time.
After searching around, I finally find a small chip amplifier, TBA820. It’s a small, 8-pins DIP type, low power at 2 Watt maximum on B-Class. Not a bad as a start. I don’t play with A or AB-Class due to heat issue. The goal is small design, almost no heat, and could be powered with battery when needed. This TBA820 chip amp should be excellent stuff.
The finished kit shown as below. With around 5 VDC power from battery, it could drive my tiny 2″ mini speaker at quite loud volume. Nice!
The detail of the kit. It has tone control also (bass and treble adjustment). But I decided to remove this section.
A closer examination on the oscilloscope. At around 5 VDC supply and about 5.6R dummy load, I could get around 0.3 Watt. Not bad at all (considering no heat and the volume is loud enough).
It started to soft clip at about 0.4 Watt.
Even worst at about 0.45 Watt.
At full volume, almost 0.7 Watt, but we had a complete clipping here 😉 I think I could get higher Wattage with higher power supply, like 9 VDC or more. But that’s not the main objective, since at 5 VDC supply, the output was more than enough.