Audio power amplifier with IC TDA7294 or TDA7293 – #Minimus

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Audio power amplifier project based in integrate circuit TDA7294 or TDA7293. Compact printed circuit board and is ideal to be used where a compact amplifier and with adequate power to be used in various applications, such as computer amplifier necessary, games, Mp3 Player, Home Theater, Sound environment, amplified Cash, etc.

Features power amplifier using integrated circuit TDA7294 or TDA7293

  • Classic application using the IC TDA7293/TDA7294
  • To assemble with TDA7294 or TDA7293 just by changing the position of a capacitor.
  • Great audio quality
  • Easy assembly.
  • Uses just a few components in the assembly
  • Reduced size board 50mm X 36mm
  • Power -/+ 18-36 VDC (Symmetrical power supply)
  • Maximum power: 80 (7294) -100 (7293) Watts RMS
  • Output Impedance: 4 at 16 Ohms.

Schematics mono power amplifier with TDA7294 / 93

Tda7294 Tda723 Minimus Power Amplifier Schematic

Suggestion of printed circuit board for assembly of mini amplifier


The transformer is connected at the power supply should be able to provide power equivalent to 1.4X the amplifier power. This power is on the DC voltage used.

In the chart below we can see what will be the maximum power, by matching Po(W) and Vs(+/-).

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4 Ohms Power Amplifier Chart

Eg: for 25V => 60W and 30V => 83 Watts. This when connected to speakers of 4 Ohms. This THD to 0.5%.
Note that for 4 Ohms the maximum is +/- 30VDC for TDA7294.

Below is the chart to TDA7294 linked into 8 Ohms – The power supply can be up until +-36VDC.

8 Ohms Power Amplifier ChartTo determine what will be its maximum DC voltage according to the transformer using the following formula: Vf = (1,4 x Vi) – 0,5
Where: Vf = final voltage
Vi = Voltage in the transformer

Ex: For a 24-0-24 transformer have:
Vf= (1,4X24) – 0,5 = 33V

Ex: Transformer for +/-28VDC
28=(1,4xVI) – 0,5 = 1,4Vi=28-0,5 = Vi =27,5/1,4 = 19,64C

With this value at hand just go on the chart and find what will power for this case!
For TDA7293, see the Datasheet
Notice the layout how to assemble the capacitor properly for TDA7294 or TDa7293.

List of material to assemble the amplifier Minimus Power Series with TDA7294 / 93

R2, R622K – Red, Red, Orange, Gold

Part Value
Resistors 1/4 W 5%
R1 33K – Orange, orange, orange, gold
R3 680 – Blue, Grey, Brown, Gold
R5 22K – Red, Red, Orange, Gold
R4 10K – Brown, Black, Orange, gold
R7 4.7 Ohms – Yellow, Violet, Gold, Gold
C1, 22µF/50V – Electrolytic capacitor
C2 1µF ~ 2.2µF 63V – Capacitor Polyester
C3, C4 10µF/35V – Electrolytic capacitor
C5, C6 100µF/50V – Capacitor Polyester
C7, C8 100nF/100V – Ceramic capacitor or polyester.
C9 22µF/50V – Capacitor Polyester (See text)
C10 100nF/63V – Ceramic capacitor or polyester.
D1 1N4148 – Semiconductor diode
IC1 TDA7293 or TDA7294* -Audio amplifier integrated circuit.
IN Audio input connector
PW Power supply connector
OUT Audio output connector
Welding, Wires, PCB, box,power supply 18 a 36 Volts DC /2,5 Amperes, etc.

Download PDF  Mirror 1

Buy TDA7293 Amplifier board in Aliexpress


LM3886 Minimus Power – Gainclone Audio Amplifier – 70 Watts RMS

Circuit simulator and PCB design software – EasyEDA


9 thoughts on “Audio power amplifier with IC TDA7294 or TDA7293 – #Minimus”

  1. A quick note on C9.

    C9 must be configure correctly for the IC you are using.
    If a TDA7294 then C9 must be connected ONLY from pin 14 to pin 6 of the IC.

    If you use a TDA7293 the C9 (the bootstrap capacitor) the chip manufacturer, ST or STMicroelectronics , says this —

    For compatibility purpose with the previous devices of the family, the boostrap capacitor can be connected both between the bootstrap pin (6) and the output pin (14) or between the boostrap pin (6) and the bootstrap loader pin (12).
    When the bootcap is connected between pin 6 and 14, the maximum supply voltage in presence of output signal is limited to 100V, due the bootstrap capacitor overvoltage.
    When the bootcap is connected between pins 6 and 12 the maximum supply voltage extend to the full voltage that the technology can stand: 120V.
    This is accomplished by the clamp introduced at the bootstrap loader pin (12): this pin follows the output voltage up to 100V and remains clamped at 100V for higher output voltages. This feature lets the output voltage swing up to a gate-source voltage from the positive supply (VS -3 to 6V).

    So you have the option, EITHER pin 14, or pin 12, BUT NOT BOTH!
    IMO, the drawing is correct in trying to show both options, however the write-up fails to indicate well that it is an option depending on which IC you are using.
    I hope this helps.

    • I bought this circuit board on E.Bay and assembled it but it doesn’t work. I am getting only a hum in the speakers. I am not sure about C9 capacitor so I coupled 2 capacitors. Can you help me to find te fault on it.


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