Amplifier parts list:
P1 = 22K Log. Potentiometer (Dual-gang for stereo)
R1 = 1K
R2 = 4K7
R3 = 100R
R4 = 4K7
R5 = 82K
R6 = 10R 1/2 watt
R7 = R22 4W Resistor (wirewound)
R8 = 1K 1/2W Trimmer Cermet (optional)
C1 = 470nF
C2,C5 = 100µF/3V Tantalum
C3,C4 = 470µF/25V
C6 = 100nF
D1 = 1N4148
IC1 = TLE2141C
Q1 = BC182
Q2 = BC212
Q3 = TIP42A
Q4 = TIP41A
Power supply parts list
R9 = 2K2 1/4W Resistor
C7,C8 = 4700µF 25V Electrolytic Capacitors
D2 = 100V 4A Diode bridge
D3 = 5mm. Red LED
T1 = 220V Primary, 15 + 15V Secondary, 50VA Mains transformer
18W Audio Amplifier Circuit Notes:
- Can be directly connected to CD players, tuners and tape recorders.
- Do not exceed 23 + 23V supply.
- Q3 and Q4 must be mounted on heatsink.
- D1 must be in thermal contact with Q1.
- Quiescent current (best measured with an multimeter in series with Q3 Emitter) is not critical.
- Adjust R3 to read a current between 20 to 30 mA with no input signal.
- To facilitate quiescent current setting add R8 (optional).
- A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 & C4. Connect C6 to the output ground.
- Then connect separately the input and output grounds to the power supply ground.
Source: redcircuits.com
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 wikipedia.org
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 wikipedia.org
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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