AV:Link Ground Loop Isolator 3.5mm Jack to 3.5mm Socket

The AV:Link ground loop isolator is a passive transformer-based device that eliminates mains hum and buzz caused by ground loops between two pieces of audio equipment connected via 3.5mm jack. The isolator sits inline between a source device (phone, laptop, tablet, MP3 player) and an amplifier, powered speaker or car stereo, breaking the ground connection while allowing the audio signal to pass through unaffected.

Ground loops occur when two devices share different earth paths in the mains supply, creating a voltage difference that manifests as a 50Hz hum or buzz through the audio system. This is common when connecting a laptop to a home stereo, a phone to a car AUX input, or a tablet to powered speakers while both devices are plugged into mains power. The AV:Link isolator eliminates this hum without requiring any configuration, battery power or external supply — it works entirely passively through audio transformer coupling.

The 600mm cable length allows the isolator to sit between devices on a desk, in a rack or in a car interior without requiring additional extension cables. The 3.5mm jack plug connects to the output of the source device, and the 3.5mm socket accepts a standard 3.5mm-to-3.5mm cable running to the amplifier or speaker. The compact 60 x 35mm body is CE-certified and housed in a lightweight plastic case that adds minimal bulk to the signal path.

What causes ground loop hum and how does this fix it?

Ground loop hum is a 50Hz buzz caused when two audio devices have different earth potentials in the mains supply, creating a voltage difference that passes through the audio cable. The AV:Link isolator breaks the ground connection using a passive audio transformer, allowing the signal through while blocking the DC voltage difference that causes the hum.

Does it need batteries or external power?

No. The isolator is entirely passive and works via transformer coupling. It requires no batteries, no mains power and no configuration — simply plug it inline and the hum disappears.

Will it affect audio quality?

Transformer-based isolators can introduce minor high-frequency roll-off and a small reduction in overall level compared to a direct connection. For most consumer audio applications (laptop to speakers, phone to car stereo) the difference is negligible and far preferable to the ground loop hum it eliminates.

What cable do I need to use with it?

The isolator has a 3.5mm jack plug on one end and a 3.5mm socket on the other. You need a standard 3.5mm-to-3.5mm cable to run from the isolator's socket to your amplifier or powered speaker. Most users already own this cable.