The ST-900V power conditioner is engineered to supply clean and stable electrical power to High-End and Hi-Fi AV equipment. At the heart of the device is a custom-designed balancing toroidal transformer (230 VAC / 115 + 115 VAC), developed by Audes, which provides isolation from the domestic network. Compared to the similarly named ST-900DC, that it is partially based on, its design has been completely revised in a way to allow the users to freely choose where and how they want to place it in their system. The ST-900V has no left, right, top or bottom sides – it can therefore be put on whichever side is more suitable for a specific setup. For this purpose, it comes with a set of rubber feet – the user can decide where they wish to attach them, or not attach them at all. Besides that, the ST-900V remains functionally identical to ST-900DC (that includes having an integrated DC blocker just like the latter) and provides all of the same benefits for audio quality.

The toroidal transformer inside the unit was designed to filter noise from the mains utilising controlled leakage inductance and capacitance. An integrated DC blocker protects the unit from harmful influence of direct current present in the mains. This feature significantly reduces transformer hum caused by DC offset, ensuring quieter operation. The outlet sockets of the ST-900V are fully isolated from the mains. The output voltages are symmetrical with respect to the artificial centre tap that is connected to the PE contacts of each socket.

The transformer has very low output impedance, due to which the ST-900V can easily supply large current surges up to the maximum power in each outlet for instantaneous power surges.

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. Additionally, the transformer includes thermal protection which switches it 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. The power supply line to the power conditioner from the distribution board must be protected by a Type C 16 A circuit-breaker.

All units of the ST-900V come supplied with a standard power cable inside the package. For further performance improvement, it is recommended to combine the power conditioner with the specially designed Audes Power Cable C13 .