FX-AUDIO-GI-01J Ground Loop Isolator, Line Noise Filter, Sound Quality First Design, RCA Input/Output GND Isolator

This ground loop isolator/line noise filter is designed with sound quality in mind, suitable for everything from car audio to professional studio use. This ground loop isolator (line noise filter) is designed with sound quality in mind, using specially ordered, ultra-low distortion transformers. These transformers are custom-made for audio applications, and are constructed using only ultra-high-precision, carefully selected components that have been filtered out for distortion exceeding the specified limits. This audio accessory prevents and reduces ground loop noise (mainly a low buzzing noise, also known as GND loop noise) in line-level signals, improving sound quality by isolating (electrically isolating) the GND of audio signals (line level) input via RCA terminals. For example, it can be used to prevent the buzzing ground loop noise that occurs in audio signal lines when a DAC and amplifier share a DC branch cable for power. It can also be used to prevent unintentional ground loop noise even without special connections such as a power branch cable. In car audio applications, it is connected between the head unit and power amplifier to prevent or reduce "humming" noise and ground loop noise generated by the car's alternator (generator).

[What is a ground loop?] When multiple devices are connected, a ground loop occurs, causing a loop in the zero-signal reference point (GND). This can result in hum (a low, continuous "buzzing" sound). While GND is generally 0V, connecting multiple devices creates a slight, error-level potential difference between the GNDs of each device. A potential difference means that current flows, and the current generated by this potential difference becomes noise unrelated to the signal. If this potential difference is very small, it will be negligible (inaudible or difficult to hear) and so inaudible that it is inaudible. However, depending on the connection conditions, device characteristics, and environment, it can become a loud, buzzing noise that interferes with listening. To give a simple example, if you branch a DC power supply and connect it to a DAC and amplifier, and then connect the DAC and amplifier with RCA cables, the connection will be power supply - power cable - DAC - RCA cable - amplifier - power cable - power supply (one loop at the branch point).

An effective way to deal with ground loops is electrical isolation. A ground loop isolator electrically disconnects and isolates the GND using a transformer, thereby eliminating the ground loop. In the above connection example, connecting an isolator between the DAC and amplifier will isolate the point where the DAC and amplifier GNDs were connected by the cold side of the RCA cables, breaking the loop. It works on even subtle levels of noise that are barely noticeable during silence or low volume, caused by currents generated by very small potential differences, and by eliminating and reducing noise, you can expect to improve the signal-to-noise ratio and quietness.

There are many inexpensive ground loop isolators available, but the reason for their low price is the precision and quality of the transformer that is their main component. When audio signals pass through a transformer, distortion inevitably occurs, and the lower the quality and precision of the transformer components, the more pronounced the distortion.

Due to the physical structure of transformers, the higher the quality and precision, the higher the cost, which directly affects the product price.

High-precision transformers designed for audio applications are extremely expensive, but low-precision transformer components are readily available as inexpensive, general-purpose components. Many products are sold cheaply using such components, but low-precision components are unsuitable for audio applications, resulting in signal distortion and degraded sound quality.

Ground loop isolators and line noise filters are commonly used as noise suppression devices for car audio applications, but because car audio is subject to a lot of external noise such as the car's engine and driving noise, "removing loud audio noise improves the perceived sound quality, even if it means sacrificing some degradation in sound quality due to sound distortion."

For this reason, many inexpensive products use general-purpose transformer components that are prone to distortion. That's why, for this product released under the FX-AUDIO brand, we custom-produced high-precision, ultra-low-distortion transformers specifically for audio, allowing them to be used in home audio systems without worrying about degradation in sound quality. By further selecting the most precise parts from these custom-made components, we have created a ground loop isolator/line noise filter that minimizes audio signal distortion and minimizes sound quality degradation as an audio product. In addition to the transformers, we also use Mil-Spec compliant metal-film resistors from DALE, a company renowned for their sound quality, for the resistors. Our commitment to sound quality in the components we use sets us apart from the specifications of other companies. When we measured the distortion rate with an audio analyzer, it was found to be 0.0005%, a significantly higher specification than inexpensive isolators, which are around 0.01%.

Ground loop isolators are common line noise filters for in-car use, but even home audio systems can be unintentionally affected by ground loop noise. We therefore set the price at a level that ignores market price and disregards profit margins, hoping that you'll give it a try. Isolators primarily designed for in-car use have issues with the transformer precision mentioned above, which causes noticeable changes in sound quality due to distortion in the transformer, often resulting in a negative impact on sound quality. As a result, they have not been used much for home audio applications. However, even home audio systems are often affected by ground loop noise. The GI-01J was originally conceived with the goal of using it in home audio systems with sound quality as the top priority, but our relentless focus on sound quality has resulted in professional-level sound quality with negligible distortion thanks to an ultra-high-precision transformer! Since it is of a quality suitable for professional use, we encourage you to try it out in both car audio and home audio environments. Once you have one, you can use it as a testing tool to check for the presence or absence of ground loop noise by simply passing it between RCA cables. So even if you don't have any obvious problems right now, it's a valuable tool to have as a ground loop noise testing tool.

Since the interior of newer cars is quite quiet, this is by no means overkill for car audio use. This is also a highly recommended product for professional use in stage sound and studio environments where ground loop noise is likely to occur due to the large number of connected devices.

[How to Use] There is no connection direction, and there is no distinction between input and output. Since there is no distinction between input and output, you can connect either end as the input terminal and the other as the output terminal via a relay between audio devices. Connection Example: [DAC] --- RCA cable --- [GI-01J] --- RCA cable --- [Amplifier]

[Important Notes] This is an isolator/line noise filter product that addresses ground loop noise. While it is effective when the noise source is a ground loop, it does not address noise caused by other factors. Please note that we cannot guarantee that you will experience noise reduction effects for all types of noise. This is a product designed solely to address ground loop noise. Therefore, if used in an environment where no ground loops exist, it may be more susceptible to noise pickup due to a weakened GND strength.

[Product Specifications] Brand: FX-AUDIO- Series: ACCESSORY SERIES Model Number: GI-01J Color: Black Warranty Period: 6 months from date of purchase Input/Output Terminals: Stereo RCA Terminals (Gold-Plated) *No distinction between input and output terminals Accessories: None Size: 40mm W x 71mm D x 25mm H (excluding protrusions) Weight: 100g Eliminates ground loop noise Uses ultra-high-precision audio-specific transformers (custom-made) Selected ultra-high-precision transformers for even greater precision Designed with sound quality as the number one priority, ensuring quality for home audio products Uses DALE resistors (MIL-SPEC), renowned for their sound quality