Greetings, everyone! In our latest project, we are once again utilizing the TDA7294 audio amplifier, renowned for its excellent price-to-performance ratio and proven integration. This project is a fusion of the previously shared “Delayed and Loud Speaker DC Protection Circuit” and “TDA7294 Stereo 2X100 Amplifier Circuit” projects. Additionally, we have incorporated a tone control layer with some minor differences in detail.
- CD4060 IC
- Resistors (R1, R2, R3)
- Capacitors (C1, C2)
- Oscillator components (R2, C2) for clock input
- LEDs (optional, for visual indication)
- Power supply (Vcc and Ground)
The circuit necessitates rectifier bridge diodes, filter capacitors, loudspeaker protection circuitry, and a tone control circuit for adjusting audio, bass, midrange, and treble levels. Additionally, there is an additional card in the design that includes a fuse and a filter card, both of which will be connected to the output of the power transformer.
High current lines ( speaker outputs, + v -v supply lines ) must be coated with solder.
Transformer to be used; 2X18V AC for 4-ohm speaker, 2X24V AC for 8-ohm speaker, 250W at home for financial …
TDA7294 STEREO AMPLIFIER CIRCUIT SCHEMATIC
The speaker protection circuit operates at 12V. I achieved this voltage regulation by adjusting it through the main power supply without using any additional sources. However, due to the single-layer PCB being etched, it’s necessary to establish this AC connection using a cable. The connection details are clearly illustrated in the diagram below. Although I can manage it, many beginners find this circuit challenging to create at home.
Furthermore, the supply voltage for the operational amplifier in the tone control section is derived from the circuit using resistors and a chopper regulator. For a 2X18V AC transformer, a 1K 1W resistor can be used, and for a 2X24V AC transformer, a 150-ohm 2W resistor and a 1K5 1W resistor are suitable for RES. The RES resistor is positioned behind the 7812 regulator.
- Very high operating voltage range (± 40 V)
- DMOS power stage
- High output power (up to 100 W music power)
- Muting/stand-by functions
- No switch on/off the noise
- No boucherot cells
- Very low distortion
- Very low noise
- Short circuit protection
- Thermal shutdown