The ST-500DC power conditioner is designed to supply electrical power to High-End and Hi-Fi AV equipment. The main element of the device is a balancing toroidal transformer 230 VAC/115 + 115 VAC designed and developed by Audes, which isolates the equipment from the domestic network.

Outlet sockets of ST-500DC are completely isolated from the mains. The output voltages are symmetrical with respect to the artificial centre tap, which is connected to earth contacts of each outlet socket. The toroidal transformer inside the unit was designed to filter noise from the mains utilising controlled leakage inductance and capacitance. The transformer has very low output impedance, due to which the power conditioner can easily supply large current surges up to the maximum power in each outlet for instantaneous power surges.

Despite the significant power rating of such transformer the construction of the power conditioner minimises harmful electromagnetic radiation. Nevertheless, do not place the power conditioner close to turntables and phono stages.

The ST-500DC comes with an integrated DC blocker. The DC blocker protects the power conditioner from harmful influence of direct current present in the mains. It significantly reduces the hum of the transformer due to presence of a DC offset in the mains.

The device is protected against overcurrent by a fuse. If overcurrent occurs, the fuse will blow, and it will need to be replaced before the power conditioner can be used again. As an additional precaution, transformer has a thermal protection, which switches a transformer off if the temperature of the transformer reaches 90 °C. Once the temperature drops to 75 °C the device will reconnect to the electrical network automatically.