Build Your 50W TDA7294 Audio Amplifier

Description

The TDA7294 amplifier module is a monolithic integrated circuit. It is intended for use as an audio class AB amplifier in hi-fi applications. It features a broad voltage range and substantial output current capacity, enabling it to deliver maximum power into both 4-ohm and 8-ohm loads. With a handful of additional components and an appropriately rated power supply, this module will provide 50W RMS into 8-ohm with 0.1% THD. The user must supply a robust heatsink with a thermal resistance of 1.4°C/W. Pin 10 serves as the MUTE input, while pin 9 activates a STANDBY mode. Maintaining permanent connections to these pins to the supply rail – consult relevant documentation [insert links] – will ensure the amplifier immediately powers on upon power-up. Adjusting the time constants R3-C6 and R4-C5 may eliminate any audible clicks during switch-on. The IC incorporates internal thermal protection, triggering mute at 145°C and transitioning to standby at 150°C. Do not operate the module without a heatsink. The TDA7294 IC's heatsink tab is internally connected to the negative supply rail. If the module is housed within an earthed metal enclosure, the IC must be isolated from the heatsink. Failure to do so will result in a short circuit to ground.

Circuit diagram

POWER SUPPLY

The IC’s maximum supply voltage is +/-40V. However, exceeding this voltage will cause the IC’s dissipation to surpass its limits. Therefore, the supply voltage should be maintained at a safe +/-30V. The mains transformer powering the module should be rated for a minimum of 80VA. To operate two modules in a stereo amplifier configuration, a transformer with a rating of 150VA is recommended.

Specifications

Parts List for Power Amplifier

All Resistors are 1/4W 1%

All Electrolytic Capacitors are Axial

Power Supply

Parts List for Power supply