My DIY on home sound amplifier worked out after a short search on the internet, I concluded that not all the amplifier IC's have same parameters. In order to get a powerful sound , you need a powerful output cascade, so to speak, with a margin, and the choice fell on the TDA7256 chip from SGS-THOMSON Microelectronics. This is a 30W bridge amplifier in class AB and a complex of protections for all life, with a balanced input and the ability to work on a 2 ohm load, which can not but rejoice.
Here is the schematic diagram :-
All nonpolar capacitors took analogs of K10-17B, not for quality sake, but for miniatures for. The scheme is standard, taken from the datasheet, only added a volume control and a resistive adder left and right channels - because I have a candy bar. Nothing prevents you from assembling and using two modules.
Previously, I did not put the totalizers and just connected both channels until one time I was pinned. An inexpensive player connected to such an amplifier began to behave extremely inadequately, stuttered, etc. Apparently some short-circuit of the outputs turned out. Since then, I definitely put in the construction of resistor-summators!
And then it raced!
So, the diagram is drawn, the details are purchased. It's time to draw a signet. The basis is also taken from the datasheet, but well-processed,
From PCB artwork to assembling the whole unit, all steps are shown below.
- Transfering the PCB artwork on copper clad sheet. The pcb design was in multiples to make it easier to print. Otherwise smaller the size , more it is difficult to print.
- After processing the pcb through etching and drilling. It has to be warnished well before soldering the parts.
- After assembling all the parts on pcb. The mono amplifier IC TDA 7256 (from ST electronics) is fixed on heat sink for proper heat dissipation. The heat sink is thoroughly mounted to absorb the vibrations. After assembling parts and wiring, the kit is ready for testing on the bench.
In the process of verification, another rake occurred, it turned out that the microcircuit starts to be excited when the input is connected to the output on the front panel of the system unit. The sound from the speaker came out in distortions, with whistles, howls and wild noise, and no poultices with pottery helped. I already wanted to get upset, but when connected to the phone the amplifier worked like a clock! I know that the ground distribution on the front of the computer is far from ideal, but not a single device has reacted to it so much, except for the headphones. More this microcircuit I did not excite anything: blush:
The sound is very pleased! It is not correct to compare it with TDA7293, after all, different weight categories and applications, but I liked the bass more with TDA7256 when listening to normal acoustics (although the price of TDA7256 bites)
So it's time to celebrate the sound on next occassion in my family.
The amplifier is snugly located on the back wall.
On the back there is a volume control and
terminals for additional speakers.
Not so good looking circuitry but it's fully working. A door handle available at home is put on the top.
I deliberetly gave it an angle to feel comfortable with the weight of the unit while carrying.
On the crash test test drive my grandmother almost choked with joy! As for the sound, it became noticeably more powerful, even in such acoustics there is a difference in the bass.
The supply is fed from a 12V battery with a capacity of 7 Ah, for a few hours, enough.
The unit is not so good looking, but it is working satisfactorily with good output sound quality. We use it often to get into the mood or enjoy our get togethers.
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Outstanding job. I love the diagram.
Thanks @sqlinsix . Actually i misplaced the actual one. This one i redraw with my hand on a quick mode. Thanks again.
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Great job :) PCB Manufacturing : pcb companies