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DIY Ground Loop Isolator: How To Make a Ground Loop Audio Noise Isolator/Hum Eliminator

A DIY ground Loop Isolator may be your only solution to having a clear radio reception. Sometimes you may experience static or distortion to the audio signal.

This constant whistle-like sound – also known as ground loop noise – can be annoying and may prevent you from enjoying your favorite jam. It can also make you miss out on crucial conversations or headlines of the morning news.

The good news is you don’t have to listen to poor radio reception for the rest of your life. Installing a ground loop isolator to your radio equipment may be the answer to your problem.

Do I need a technical person to build a ground loop isolator? No, you do not. You can construct your ground loop isolator all by yourself by using a few tools and materials that are available at your local hardware shop.

What is Ground Loop Noise and what Causes it?

Understanding the concept of ground loop noise is key to understanding the need for a ground loop isolator.

Ground loop noise is nothing but static or noise that affects an audio output of a receiver.

It propagates through a radio system when the shield of the wire that connects to a receiver carries a combination of noise and audio signal to the ground system.

Ground loop noise manifests because ground cables do not possess perfect conductivity.

As a result, noise filters into an audio receiver via the common ground point because it connects to various other electrical devices.

This noise causes severe audio distortions thereby, making tuning and listening to the radio difficult.

Ground loop noise can occur due to several reasons. These causes are:

  • Ground loop noise occurs when a radio system draws power from a power system.
  • The generated noise is primarily due to the frequency of oscillation of the powerline and its harmonics, which introduce noise into the audio output of a radio system.
  • This noise is more problematic when the radio system connects to an unbalanced speaker system. However, ground loop noise is still a source of concern even with balanced speaker systems.
  • Another cause of ground loop noise is when a difference in voltage exists between two different ground connections of separate electrical devices connected to the same ground system within an enclosed system.
  • This type of noise generated from the difference in voltage is the most severe and can be hard to mitigate.
  • Magnetic capacitance or inductance on a signal cable can cause ground loop noise.
  • The capacitance from a power transformer that feeds the circuit, which powers a radio receiver, can introduce ground loop noise onto the audio circuitry ground system.

Why is a ground loop isolator needed?

Installing a ground loop isolator is the best way of getting rid of ground loop noise. Nonetheless, there are other ways of reducing ground loop noise:

  • Minimization of connection impedance (resistance) by using high-quality wires for both audio and power connections,
  • The use of balanced audio devices and cables all connection points,
  • Through the electric isolation of all-metal cases of devices around the radio receiver.

What is a ground loop isolator?

A ground loop isolator is an electrical device that minimizes interference within a ground loop system by reducing the paths to the ground to only one way.

This device can eliminate interference by balancing the voltage across all ground points within a circuit to the same value.

As a result, it removes any potential difference that may exist within the ground circuitry.

In simple terms, it removes electricity from sound and vice versa within a system. Therefore, it removes electrical noise within the audio circuitry of a radio receiver.

A ground loop isolator consists of an input, an output, and a transformer in between.

Where is a ground loop isolator used?

Apart from removing noise from an audio signal, a ground loop isolator offers a lot to electrical systems, in particular, systems with audio and video capability. Some of the most common uses of ground loop isolator are:

  • To eliminate interference or noise from speaker systems with multiple speaker units,
  • To remove the engine humming sound that filters into the audio output of a car radio,
  • To protect humans from being shock by electric current when using electrical devices,
  • To minimize or remove radio interference in routers and cascade antenna systems that connect multiple antennas.

How does a ground loop isolator work?      

It isolates noise from a ground loop system by stepping up or down the voltage from one ground coupling point to another via a transformer on the same ground loop circuit.

Ultimately, the input and output of the transformer become equal the moment voltage passes through the isolator system.

As a result, interference and noise produced from unwanted voltage spikes get eliminated from the ground loop system.

Therefore, the audio circuits of a receiver can generate a sound that is free of static by blocking AC of low frequency and DC currents from interfering with the high-frequency audio signal.

The more crucial advantage of a ground loop isolator is that it is relatively cheap to construct and install. You can build and install your isolator without breaking the bank.

How Can I Make DIY Ground Loop Isolator?

The construction of a simple ground loop isolator is an easy task. With the suitable materials, tools, and a detailed step-by-step guide, you can DIY a ground loop isolator in a matter of minutes.

However, be sure to get the proper materials and tools for the job. Using the wrong materials and tools can make you waste your time, energy, and money without achieving anything meaningful.

Required Materials and Tools

To construct a functional ground loop isolator, you will need the following materials and tools.

  • Audio Isolation transformers.
  • Female RCA connectors.
  • A soldering iron.
  • Solder flux.
  • A cutter.
  • Electrical tape.
  • Enclosure box and other useful items.

Audio Isolation transformers

  • You will need an audio isolation transformer with a 1:1 turn ratio.
  • If the transformer has four terminals on each side of its primary and secondary sides, you will need only one isolation transformer. If it has only two terminals, you will need two transformers.
  • You can get an isolation transformer from an older device in your home. For example, you can get it from an old modem that connects the computer to the internet. All you need to do is solder it off.
  • Alternatively, you can get an audio transformer for under $10 on the internet. You can even get less from your local hardware shop. With $20, you get two transformers of 600 Ohms each and some change.

Female RCA connectors

  • You will require four female RCA connectors as each will connect to the two terminals of a transformer on either side.
  • You can equally get female RCA connectors off old unused electrical devices.
  • Alternatively, you can buy the four RCA connectors for as little as $4 per connector.

Soldering Iron

  • You will need a soldering iron to solder off parts if you want to make use of old isolation transformers and female RCA connectors.
  • Equally, you will need to solder on wires onto devices using a soldering iron.
  • With $15, you can get a powerful 60W soldering iron if you do not already own one.
  • You can also pay more to get an iron that comes with a complete kit of accessories and a soldering stand.

Solder

  • Soldering tin-lead solder allows you to create a connection between wires and electronic devices through the process of soldering.
  • It is a material that quickly melts when exposed to the heat of a soldering iron.
  • It is an alloy of tin and lead.
  • If you purchase a complete soldering kit, you will likely get all the solder you need to get your ground loop isolator up and running.
  • Nonetheless, you can get a complete role of solder for less than $5.

Solder flux

  • Solder flux is a helpful material that makes the soldering process easy.
  • It allows you to make smooth connections by clearing metal surfaces as it removes oxides and other debris.
  • A container of solder flux gel is cheap and will not cost you more than $10.
  • However, you can make soldering connections without necessarily using a solder flux.

Cabling

  • You will need a small wiring cable to connect and solder various parts.
  • 16-gauge wire is ideal for making a ground loop isolator.
  • A roll of good 16-gauge of wire costs less than $20.

Cutter

  • A cutter is a device that will allow you to cut wires, the sheath of cables, and cut other materials.
  • If you do not have it somewhere in your home, a simple cutter should cost about $5.

Electrical Tape

  • An electrical tape is an essential tool that lets you insulate surfaces of wire and metals that conduct electricity.
  • An electrical tape can be as cheap as $1.

Enclosure Box and Other Useful Items

  • An enclosure box is made of plastic or a non-conductive material.
  • You use it to house and protect the audio isolation transformer and the wires connected to it.
  • Additionally, it serves as a surface for you to affix the female RCA connectors with the output facing outwardly.
  • Any simple non-conductive enclosure around the house can hold the audio isolation transformer, its terminals, wirings, and the terminal parts of the female RCA connectors.
  • You can also purchase a project box from your local hardware shop for under $5.
  • Keep around any item you think you need for the construction. Some glue of any kind can come in handy.

Step by Step Guide on How to Ground Loop Isolator DIY

Constructing a ground loop isolator is pretty easy. You do not need technical training or a technician to make this simple device.

Armed with the right tools, materials, and the step-by-step guide below, you can have a functional isolator in less than 30 minutes.

Step 1:

Sketch the layout of the proposed ground loop isolator with all the components and wirings included.

Step 2:

Have all the required components and tools at your disposal. If you have a working surface, arrange every item neatly on the table.

Switch on the soldering iron to get it hot and ready for use. Have the solder flux ready in the event you may need it.

Step 3:

Use the cutter and cut a reasonable amount of cabling into eight suitable lengths. Use it to expose the conductor underneath the sheath on both sides.

Step 4:

Solder one side of each wire to each terminal of the two audio isolation transformers. Therefore, two sets of cables will connect to the primary and the secondary side of each transformer.

Step 5:

Solder the other sides of each set of wires onto the four female RCA connectors. Use the electrical tape to bundle cables together.

Step 6:

Cut out four openings where the output female RCA connectors can fit through and hold. If the cutter does not cut through, you can use the tip of the soldering iron to make a hole.

Step 7:

Glue the bases of the isolation transformers onto the surface of the enclosure box. Place the face of each female RCA connector through the carved-out openings.

Add some glue around each connector so that it sticks to the box. Finally, close the box and connect the newly formed ground loop isolator.

Connecting the Ground Loop Isolator

On the primary side of the ground loop isolator, connect the two male RCA connectors two their female counterparts.

Likewise, attach the other two male RCA connectors from the speaker to the secondary side of the ground loop isolator.

Power your radio system, and tune in to any station. You will have a clear audio output free of noise, static, and any form of interference.

Conclusion

Creating a simple DIY ground loop isolator device is straightforward and easy.

You can quickly produce a working system that filters out noise from the output of your speakers or any other audio-extending device.

With the right tools, materials, and the step-by-step guide described earlier, you will have a clear audio output from your radio system.

The basic tools and materials you need to complete this project include audio isolation transformers, female RCA connectors, a soldering iron, a solder, cabling, a cutter, an electrical tape, an enclosure box, and other useful items.

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