For the safe operation of audio power amplifiers, each semiconductor has to be operated within its safe operating area (SOA). Usually, conventional protection techniques are used to protect the components, where the maximum current is usually limited to a low and non-critical value. In addition, the temperature at the heat sink of the power components is measured in a simple way and when the critical temperature range is reached, the load is switched off or the output voltage is reduced. In general, these protections are sufficient and avoid overloading the electronics. However, a very high safety margin must also be taken into account — the maximum possible performance of the semiconductor components cannot be fully utilized, because the actual junction temperature inside the semiconductor components would have to be known. With Dynacord's Junction Temperature Modeling (JTM), the temperature is modelled in real time, based on the operating parameters such as operating voltage, housing temperature, output current and output voltage. This is done using an advanced continuously monitoring algorithm, which is applied to all the important semiconductors in the amplifier. Relevant operating parameters such as current and voltage are continuously measured. The resulting power loss of the components is fed to a comprehensive temperature model of the cooling system. Then the actual junction temperature of the power semiconductors can be calculated in real time. This approach allows an optimized usage of the semiconductor components, which ultimately leads to significantly more output power and uncompromising reliability.