Audio hum and ground noise isolator

Our ATG00101 adapter breaks the electrical connection between two devices to prevent hum caused by equipotential bonding currents. This effect is a common cause of hum. However, there may be other causes of noise, in which case the ground isolator will not help. The following explanation will help you identify the cause:

What are ground loops?

This interference occurs when different components of an AV system have different electrical potentials. This leads to annoying noise and unwanted effects in the audio and video output. Often, such noise manifests as a 50 Hz hum. This is because 50 Hz is the AC frequency of our 230 V mains supply. In audio connections, this can trigger a low-frequency hum with a frequency of 50 Hz. 

Why humming or audio interference occurs

This interference occurs due to an imbalance in the electrical potential between the connections. When two devices with different electrical potentials are connected, an equalising current flows from the higher to the lower potential. This is because the devices are connected via earth. The audio, video or antenna cable connects the two devices. Different circuits therefore create potential differences, which are perceived as interference. 

Devices with IEC power plugs in particular – those large 3-pin power plugs found on PCs and stereo systems – are the source of such problems.

You can test this by setting up a minimal setup with just two devices and leaving out any unnecessary connections. For example, just a media player and a TV without antenna. Then gradually add other devices and cables. If you hear a humming noise after connecting the aerial cable or an active speaker, there is a classic ground loop.

What does a ground isolator do?

The ATG00101 ground isolator isolates the connected devices from one another. This disconnects the electrical circuit in audio connections. The sound is then transmitted via induction. There is therefore no longer a direct conductive connection. This prevents 50Hz humming caused by a ground loop. 

Here, the ATG00101 cannot help:

However, if a hum occurs on a device that is not connected to another, or if the second device is not powered via the mains or an antenna connection, there cannot be a ground loop. The ATG00101 cannot help in this situation. For example, if only a pair of headphones is connected somewhere and is humming. Or if a laptop is running on battery power and a connected audio device is humming.