AU-100 Dual-Channel Audio Isolator, Ground Loop Hum Eliminator, XLR / 6.35 mm TRS / RCA / 3.5 mm AUX, 20 Hz-20 kHz

1. Product Name

The AU-100 is a dual-channel audio isolator in a desktop enclosure. It sits in the signal path between two devices that share a common power ground, eliminating the hum and buzz that ground loops induce on the line. Each channel has its own transformer, so the two channels are fully isolated from each other and from the remote devices.

Why a transformer instead of a filter. A ground loop is a loop, not a noise source, so filtering the audio only treats the symptom. Breaking the ground loop path eliminates the loop itself: the signal still passes through the transformer, but the current that was circulating in the cable shield has nowhere to go. That is why this product is specified for 50/60 Hz AC mains noise — the frequency the loop carries.

2. Construction and Materials

Two transformers, one per channel. Each channel is isolated through a 600:600 permalloy transformer sealed in a shielded can, marked 600:600 and 1+1:1+1 on the can. The shielded can is what makes this product both quiet and isolated: a transformer without a shielded can is both a component and an antenna. One point to confirm when ordering: the renderings included in this listing show two different can markings, one unit with ZXY2207 and another with PC-1 PRO+, both 600:600. Please check which transformer is actually fitted in your batch.

Enclosure and PCB. Heavy-duty extruded aluminum enclosure with a black brushed finish, featuring an Isolator nameplate and AU-100 marking. Inside, a double-shielded PCB carries the two transformer cans, connector modules, and function switches with silver-plated contacts.

3. Features

Two independent channels, A and B. Each channel has its own transformer, so the two paths are isolated from each other and from the remote devices.

Two 600:600 permalloy transformers in sealed shielded cans. One per channel. The shielded cans both shield and secure the windings, which is critical in racks full of switch-mode power supplies.

Five connector types on each side. Balanced XLR, 6.35 mm TRS/TS, gold-plated RCA, and 3.5 mm AUX, so there is no need for the usual chain of adapters between a mixer and a computer.

Balanced-to-unbalanced conversion, bidirectional. Balanced outputs can drive unbalanced inputs, and unbalanced sources can drive balanced lines.

One-touch LIFT/GND switch. Located on the input panel, for handling loops that bypass the transformer due to a second ground path.

Blocks 50/60 Hz AC mains noise. The frequency carried by power ground loops and the hum this product is specified to eliminate.

100% galvanic isolation. No conductive path between input and output; the signal is transferred via magnetic coupling.

Flat response, ±0.2 dB from 20 Hz to 20 kHz. Covers the entire audio band, stated as a tolerance rather than a "transparent" claim.

THD below 0.001% at 1 kHz, CMRR above 90 dB at 60 Hz. Distortion and common-mode rejection ratio are stated as concrete numbers, making it easy to compare against other products on paper.

Extruded aluminum enclosure, double-shielded PCB. The rigid enclosure doubles as a shield, and the PCB is shielded on both sides.

4. Advantages

Breaks the loop, not the signal. A ground loop is a circuit; breaking it eliminates hum at the source rather than cutting it out of the program material.

One unit replaces a chain of adapters. XLR, 6.35 mm, RCA, and 3.5 mm on both sides, so whatever is on stage can be connected directly.

Mixed equipment is no longer a problem. Balanced mixer gear and unbalanced consumer devices can be converted in both directions through the same unit.

Stays quiet in hostile rack environments. Sealed permalloy shield cans and a double-shielded PCB keep external magnetic fields out of the windings.

A switch for stubborn situations. When the transformer alone cannot break the loop, the LIFT position on the input panel disconnects the ground.

No power supply required. The unit is passive, so there is no power supply to fail and no active stage introducing its own noise.

5. Application Scenarios

Studio recording. Between mixers, audio interfaces, and outboard gear, where shared grounds are the norm and hum is unacceptable.

Live sound systems. Between stage boxes, mixers, and amplifiers, where ground paths run through long cable shields.

Broadcast and installation. Conference rooms, lecture halls, and fixed AV racks, where cabling is installed once and must stay quiet for years.

Video conferencing and simultaneous interpretation. Bringing computer audio into a hall system, i.e., the scenario shown in the renderings: laptop → isolator → projector.

6. Technical Specifications

The table below reproduces the specifications for the AU-100 as given in the accompanying documentation. Where no value is provided, the cell explicitly states this rather than borrowing data from another model. Acoustic figures come from the supplier's specification panel for this model; the measurement setup behind them is not described.

6.1 Overview

6.2 Acoustic Performance

6.3 Connectors and Panels

6.4 Construction

LIFT/GND switch. One-touch operation, located on the input panel between the AUX jack and the B-channel XLR. The position marked LIFT disconnects the ground; the position marked GND keeps it connected. This switch is for cases where the transformer alone is not enough, i.e., when a second ground path exists through rack rails or a distribution panel.

6.5 Quality and Testing

7. Ordering Information

This product is ordered under the model AU-100, with ZXY AUDIO marked on the enclosure. It is a dual-channel isolator with five connector types on both panels and a LIFT/GND switch on the input side. Before ordering, confirm the actual transformer model fitted (the renderings show both ZXY2207 and PC-1 PRO+ shield cans, both 600:600) and confirm the packaging method, as the supplied documentation does not specify packaging or lead time.

Certification: no certificates or test reports are attached to this listing, so this page makes no compliance claims, and the rendering with a row of certification marks has not been used. If the listing requires a certificate, refer to the certificate number itself.

Brand / Manufacturer: ZXY AUDIO, Shenzhen Zhi Xiang Yuan Electronics Co., Ltd. http://www.zxycoil.com