WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions.
Click here to have your audio equipment measured for free!
It is a function of the amplifier IC they chose. It requires a minimum output impedance or it will oscillate. It also helps as a protection circuit against momentary shorts as you plug and unplug things although I think the Topping products have a protection circuit for this.