Friday, January 13, 2012

50W Power Amplifier Circuit using STK084

50W Power Amplifier Circuit using STK084

This is the circuit diagram of 50W power amplifier circuit which built based on single power amplifier chip of STK084. It's an well-known old IC for audio frequency (AF) amplifier.

This circuit requires dual polarity / split power supply with maximum supply of ± 50. The recommended supply is ± 35 / 2-3A DC current. You may use this split power supply circuit for the amplifier. Use 28V center tap transformer to get about ± 36V output.

Technical Details:

Power output: 50W
RL : 8 Ohm
TDH : 0.2 %
Rin : 52K
Gain : 26.4 dB
Noise : 0.3 mV

Take a note that heatsink is required to be mounted on the power IC since it will going to hot when operated and deliver high power output (high audio volume level).

About Audio Amplifier
An audio amplifier is an electronic amplifier that amplifies low-power audio signals (signals composed primarily of frequencies between 20 - 20 000 Hz, the human range of hearing) to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain.

The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification, equalization, tone control, mixing/effects, or audio sources like record players, CD players, and cassette players. Most audio amplifiers require these low-level inputs to adhere to line levels.

While the input signal to an audio amplifier may measure only a few hundred microwatts, its output may be tens, hundreds, or thousands of watts. More explanation about power audio amplifier can be found at

This is a video tutorial about how to a very simple audio amplifier based on the LM386 amplifier chip. It can be built for less than $20 (or might be less than $8 in some countries) and used to amplify any low level audio signal including a guitar, bass or mp3 player.

Watch the video:

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