Are you experiencing a humming sound coming from your turntable?
It could be due to a ground loop, which can be easily fixed by properly grounding your phono preamp. But where do you start?
In this article, we’ll guide you through the process of finding the grounding terminal and connecting your phono preamp to your amplifier or receiver.
Whether you’re a seasoned audiophile or just starting out, this step-by-step guide will help you get the most out of your turntable setup.
So, let’s dive in and learn how to ground a phono preamp!
How To Ground A Phono Preamp
Step 1: Identify the Ground Wire
The first step in grounding your phono preamp is to identify the ground wire. This wire is commonly green, but it can also be a different color depending on your turntable model. If your turntable is new, the wire will most likely be folded and covered with a twist tie under the chassis.
To access the ground wire, you’ll need to uncover this wrapping and locate the unconnected copper spade connector.
Step 2: Find the Grounding Terminal
The grounding terminal on your amplifier or receiver will be marked “ground” and is typically located on the back of the unit. It can be a metal post with a knurled shaft or a simple screw terminal.
You’ll need to unfasten the grounding terminal to connect it to your phono preamp.
Step 3: Connect the Ground Wire
Now that you’ve located both the ground wire and grounding terminal, it’s time to connect them.
Take a piece of wire and connect one end to the ground screw on your phono preamp. Then, connect the other end of the wire to a similar ground screw on your amplifier or receiver.
It’s important to note that you should not connect the ground wire to the mains protective earth. This can cause electrical interference and potentially damage your equipment.
Step 4: Test Your Setup
Once you’ve connected the ground wire, it’s time to test your setup. Play some music and listen for any humming or buzzing sounds. If you still hear unwanted noise, try adjusting the position of your equipment or using a different outlet.
If you’re still experiencing issues, double-check that all connections are secure and that you’ve properly grounded your phono preamp.
Understanding Grounding In Audio Systems
Understanding grounding in audio systems is critical to maintaining high-quality audio output and avoiding unwanted noise. A ground loop occurs when multiple points in an electrical circuit have different grounding potential, resulting in electrical noise, humming, and alternator whining in audio systems. It’s essential to follow best practices for grounding specific car audio components or follow recommended grounding procedures located within your car audio equipment’s user manual.
When we talk about “ground,” we also mean “earth.” However, from an electrical perspective, the closest we get to a real earth ground is one of the prongs on an AC plug in the wall. To avoid ground loops and hum when stringing together a number of components that may use different grounding systems, it’s best to use one ground point if possible. Star grounds are the best option, which is a collection of grounds all meeting at the same point in a system.
Most well-designed audio equipment utilizes star grounding internally. Still, when hooking together products as a system, it’s crucial to try and utilize one ground point if possible. Dedicated AC lines form star grounds, and if each piece of gear is plugged into its dedicated outlet, you’ve formed a star ground.
The signal ground is the reference point from which a signal is measured. In the case of amplifiers, this is the audio signal that has frequencies between 20 Hz and 20,000 Hz or more. It also acts as a reference point for power supply voltages and the like. A clean signal ground is required for audio devices to maintain high signal-to-noise ratios and avoid noise induction into the signal.
Amplifiers typically deal with relatively low-voltage audio signals (particularly at their inputs) and relatively high-voltage power supplies. Having a distinct signal ground for each distinct amplifier circuit is possible and even suggested to keep ground-induced noise to a minimum in the signal. The signal ground should be connected to the chassis ground of the amplifier at a single point.
It’s beneficial to have the signal ground fluctuate along with the chassis ground to keep the relationship between signal and chassis ground. This signal ground may be connected to earth ground through the chassis ground. A system where the signal ground is not connected to another circuit or earth is often called a floating ground or “double-insulated.”
Identifying The Grounding Terminal On Your Phono Preamp
Identifying the grounding terminal on your phono preamp is crucial to properly grounding your turntable setup. The grounding terminal is typically located on the back of the phono preamp and will be marked “ground.”
It can be a metal post with a knurled shaft or a simple screw terminal. Take a close look at your phono preamp and locate the grounding terminal before proceeding with the grounding process.
If you’re having trouble locating the grounding terminal, consult your phono preamp’s manual or contact the manufacturer for assistance. It’s important to properly identify the grounding terminal to ensure a secure and effective connection with your turntable’s ground wire.
Connecting The Phono Preamp To Your Amplifier Or Receiver
After grounding your phono preamp, the next step is to connect it to your amplifier or receiver. This process involves using audio cables to transfer the signal from the preamp to your amplifier or receiver.
Step 1: Identify Your Audio Inputs
Before connecting your phono preamp, you’ll need to identify the audio inputs on your amplifier or receiver. These inputs are typically labeled “phono,” “line,” or “aux,” and can be found on the back of the unit.
Step 2: Connect Your Audio Cables
Once you’ve identified your audio inputs, it’s time to connect your audio cables.
Take one end of your RCA cable and plug it into the output of your phono preamp. Then, plug the other end of the cable into the corresponding input on your amplifier or receiver.
It’s important to note that you should use shielded RCA cables to reduce interference and noise in your audio signal.
Step 3: Power On Your Equipment
After connecting your audio cables, it’s time to power on your equipment. Turn on your phono preamp first, followed by your amplifier or receiver.
Step 4: Test Your Setup
Once everything is powered on, test your setup by playing some music. If you hear sound coming from your speakers, then congratulations! You’ve successfully connected your phono preamp to your amplifier or receiver.
If you’re experiencing any issues with sound quality or volume, try adjusting the settings on your equipment or consulting the user manual for troubleshooting tips.
Troubleshooting Grounding Issues And Humming Sounds
Sometimes even after grounding your phono preamp, you may still experience humming sounds. This could be due to a ground loop caused by other equipment in your audio system. Here are some troubleshooting steps to follow:
Step 1: Identify the Source of the Hum
The first step is to identify the source of the hum. Start by unplugging all sources from your amplifier or receiver except for your turntable. If the hum disappears, then one of your sources is causing the issue.
Step 2: Reconnect Sources One at a Time
If the hum persists after disconnecting all sources except for your turntable, then it’s likely a ground loop issue. Reconnect each source one at a time and listen for the hum to return. The offending piece of equipment will be the one causing the ground loop.
Step 3: Check for Cable TV Connection
Ground loops are common when video equipment is connected, especially cable TV connections. If you have a cable TV connection, try disconnecting it and see if the hum disappears.
Step 4: Adjust Equipment Position
Sometimes, the position of your equipment can cause ground loops and humming sounds. Try moving your turntable and other equipment to different locations to see if it makes a difference.
Step 5: Use a Different Outlet
Electrical interference can also cause humming sounds. Try plugging your equipment into a different outlet to see if it makes a difference.
By following these troubleshooting steps, you should be able to identify and fix any grounding issues and humming sounds in your audio system. Remember to always properly ground your phono preamp and avoid connecting the ground wire to mains protective earth.
Advanced Tips For Improving Grounding In Your Turntable Setup
If you want to take your grounding setup to the next level, there are a few advanced tips you can try:
1. Use a separate ground wire for each piece of equipment: Rather than connecting all of your equipment to one ground wire, use a separate wire for each piece of equipment. This can help reduce the risk of ground loops and improve overall sound quality.
2. Upgrade your ground wire: While any 18 or 20-gauge wire can work effectively as a ground, upgrading to a higher-quality wire can improve sound quality even further. Look for wires with lower resistance and better shielding.
3. Use a grounding box: A grounding box is a device that connects to your phono preamp and provides a dedicated grounding point. This can help reduce the risk of ground loops and improve overall sound quality.
4. Experiment with different grounding points: The best spot for grounding your turntable may not always be obvious. Try experimenting with different grounding points to find the spot that creates the best connection and emits less hum. A simple way to test for the best spot is to touch the end of the wire on different areas of the turntable’s chassis (with the power turned back on, and taking care not to touch any of the metal with any part of your body).
By following these advanced tips, you can improve the grounding in your turntable setup and achieve even better sound quality. Remember, always be careful when working with electrical components and never connect a ground wire to the mains protective earth.
