If you’re looking for a DIY amplifier project made with a minimum of parts, this is the build for you. [Rouslan] created a 70 watt class D amplifier using an ATtiny45 and just a few dollars worth of additional components.
A class D amplifier simply switches transistors of MOSFETs on and off very rapidly. By passing the signal produced by these MOSFETs through a low pass filter and connecting a speaker, a class D amp is able to amplify a signal very efficiently. Usually, these sort of amp builds use somewhat esoteric components, but [Rouslan] figured out how to use a simple ATtiny microcontroller to drive a set of MOSFETs.
In [Rouslan]‘s circuit, the audio signal is passed into the analog input of an ATtiny45. Inside this microcontroller, these analog values are sent to the MOSFETs through a PWM output. [Rouslan] threw in a few software tricks (explained in revision 2 of his build) to improve the sound quality, but the circuit remains incredibly simple.
[Rouslan] posted a video going over the function of his ATtiny amp, and from the audio demo (available after the break), we’re thinking it sounds pretty good. Amazingly good, even, if you consider how minimalistic this 70 watt amp actually is.
Thanks [Alec] for sending this one in.