Schematic Volt

A very simple high efficiency 60 watt stereo power audio amplifier circuit can be designed using the STK433-730-E hybrid IC designed to be used in class AB audio power amplifiers.

This class AB audio stereo power amplifier circuit will provide an output power of 30 watt on two channels at a 6 ohms load . Also this AB audio power amplifier circuit supports a 4 ohms load . For maximum rating on a 6 ohms load this stereo power amplifier project must be powered from a dual 28 volt very good filtered DC power source . For maximum rating on a 4 ohms load this 60 watt stereo power amplifier must be powered from a dual 25 volt DC power source , but typically is recommended a dual 18 volts DC power source on a 4 ohms load .
If is used to provide maximum ratings the output power will have a maximum 10% THD .
Exceeding the maximum ratings, even momentarily, may cause damage to the hybrid IC.
Use the hybrid IC so that the voltage applied to the stand-by pin (pin 13) never exceeds the maximum rating. The power amplifier is turned on by applying +2.5V to +5.5V to the stand-by pin (pin 13).

An output limiting circuit for substrate overheating is incorporated to protect the hybrid IC from the heat generation exceeding the maximum rating.
The load short-circuit protection circuit is activated when it has detected an overcurrent in the output transistors.
However a thermoplastic adhesive resin is used to secure the case and aluminum substrate.
When the IC supply voltage, VCC, is .18V and RL is 4 , the total power dissipation, Pd, within the hybrid IC, will be a maximum of 33Wat 1kHz for a continuous sine wave signal according to the Pd-PO characteristics.
Therefore, the value of 3.10.C/W, is the required thermal resistance of the heat sink.