CONTENTS :
A. Introduction
B. Pre-amplifier circuit using LA3161
C. Filters like stereo rumble filter
D. Stereo control module
E. Audio Power Amplifier using STK459
F. Miscellaneous
Here i have presented material in making a simple HI-FI music system. I have done the explanation in modules, so any one interested in only a particular section can also refer to this documentation.
Introduction
The system is a cassette player with aux input for CD, and other stuff. The construction is highly affable and agog especially while making from scrap. The block diagram can be visualized in steps as: -1.Pre-amplifier
2.special filters (like hum filter/stereo rumble filter) (OPTIONAL)
3.Buffer and 1-2 stage amplifier
4.Stereo control module or a graphical equalizers (stereo is optional)
5.A HI-FI power amplifier unit
6.A impedance matching unit and BASS/TREBLE separating unit or Cross Over Network
Other required items are: -
7.Power supply unit: -
a.To The mechanism unit MOTOR
b.Pre-amplifier, filters, equalizers etc
c.To the main power amplifier.
8. Fancy items like dancing LED.
I have not documented the 7th power supply unit and 6th unit which is the impedance matching network and it's job is to match the output of the power amplifier to the respective speakers, as we know that there are three types of speakers namely the TWEETER, SQUAKER, BASE SPEAKER or WOOFER .So for best alimentary it is required that the right frequency goes to the appropriate speaker. So the highest frequencies are played by tweeter, mid frequency by squawker and the low frequency by the woofer. This job is done by the 6th unit and is readily available in the market.
The power supply unit is a piece of cake and can be easily done. Normally 12v is required by the motor and pre-amp, filter, equalizer, but the amplifier which i used requires +/-24vDC WOW! So all I can suggest is you go for IN5402 types of diodes and not the IN4007 diode due to the high current requirement, if you are going for a simple tiny amplifier say the LM386 which can be used in radio do not need this, so a 12v is enough for the application. Normally the buffer is merged in the equalizer circuit, and true in the circuit i have supplied.
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