Vinyl records have been making a comeback in recent years, and with that comes a renewed interest in the equipment needed to play them.
If you’re new to the world of turntables and amplifiers, you may have come across the term “phono” and wondered what it means.
In short, a phono input is a specialized audio input that allows you to connect a turntable to an amplifier or receiver. But why is this necessary? And how does it work?
In this article, we’ll explore the world of phono inputs and explain everything you need to know about this essential component of any vinyl setup.
What Does Phono Mean On An Amplifier
A phono input, also known as a phono stage or phono preamp, is a specialized audio input found on many amplifiers and receivers. It is designed to accept signals from analog turntables, which produce a very low-level output signal that needs to be amplified and equalized before it can be played through speakers.
The reason for this is that vinyl records are recorded with a specific frequency response curve, known as the RIAA equalization curve. This curve boosts the higher frequencies and reduces the lower frequencies during recording, which helps to reduce background noise and conserve physical space on the record.
However, during playback, this frequency response curve needs to be reversed in order to recreate the original sound. This is where the phono input comes in – it includes standardized RIAA equalization circuitry that can boost and equalize the signal from the turntable, allowing it to be played back with accurate sound reproduction.
Without a phono input, the signal from a turntable would be too weak and distorted to be played through speakers. This is why many modern amplifiers and receivers no longer include a built-in phono input – they assume that most users will be listening to digital music formats like CDs or streaming services.
The Basics: What Is A Phono Input?
A phono input is a set of input jacks, usually mini jacks or RCA connectors, located on the rear panel of a preamp, mixer or amplifier. It is specifically designed to accept signals from analog turntables, which produce a very low-level output signal that needs to be amplified and equalized before it can be played through speakers.
The phono input circuitry includes standardized RIAA equalization circuitry that can boost and equalize the signal from the turntable, allowing it to be played back with accurate sound reproduction. This is necessary because vinyl records are recorded with a specific frequency response curve, known as the RIAA equalization curve. This curve boosts the higher frequencies and reduces the lower frequencies during recording, which helps to reduce background noise and conserve physical space on the record.
During playback, this frequency response curve needs to be reversed in order to recreate the original sound. Without a phono input, the signal from a turntable would be too weak and distorted to be played through speakers.
While many modern amplifiers and receivers no longer include a built-in phono input, some newer low-cost turntables include built-in amplifiers to produce line-level outputs. Additionally, devices are available that perform the conversion from phono to line level for use with computers, or older amplifiers or radio receivers can be used. DJ mixers typically have multiple phono inputs, along with line inputs that also use RCA connectors.
Why Do You Need A Phono Input?
If you are a vinyl enthusiast and enjoy listening to music on a turntable, then a phono input is an essential component for your audio system. Without a phono input, the sound quality of your vinyl records will be severely compromised, and you will not be able to experience the full range of sound that vinyl has to offer.
A phono input is designed specifically to amplify and equalize the low-level signal from a turntable, which is necessary for accurate sound reproduction. The RIAA equalization curve used in vinyl recording and playback is unique to turntables and cannot be replicated by other audio inputs, such as line or AUX inputs.
Furthermore, using a phono input can help reduce background noise and improve the overall clarity and detail of your vinyl recordings. This is because the circuitry in a phono input is specifically designed to minimize noise and distortion, resulting in a cleaner, more natural sound.
In short, if you want to get the most out of your vinyl collection and enjoy high-quality sound reproduction, then a phono input is an essential component for your audio system.
How Does A Phono Input Work?
A phono input works by amplifying and equalizing the low-level signal produced by a turntable. When a vinyl record is played, the needle on the turntable’s cartridge picks up vibrations from the grooves in the record, which are then converted into an electrical signal.
This electrical signal is very weak, typically only a few millivolts, and needs to be amplified before it can be played through speakers. However, simply amplifying the signal would result in inaccurate sound reproduction, as the RIAA equalization curve used during recording needs to be reversed during playback.
This is where the phono input comes in – it includes specialized circuitry that can both amplify and equalize the signal from the turntable. The RIAA equalization curve is applied to the signal, effectively reversing it so that it can be played back with accurate sound reproduction.
The phono input typically includes RCA connectors or mini jacks on the rear panel of an amplifier or receiver. Some modern turntables include built-in phono preamps, which can produce line-level outputs that can be connected directly to an amplifier’s line input. However, these built-in preamps may not provide the same level of accuracy as a dedicated external phono preamp or stage.
Understanding Phono Preamps
A phono preamp, also known as a phono stage, is an electronic component that performs two critical functions: amplifying the signal level and applying the RIAA equalization curve. The signal from a turntable cartridge is very small and needs to be amplified up to several hundred times its original size before it can be played through speakers. The phono preamp is responsible for this amplification process.
In addition to amplification, the phono preamp applies the RIAA equalization curve to the signal. This curve is necessary to reverse the frequency response curve applied during recording, which boosts higher frequencies and reduces lower frequencies. Without this equalization, the sound would be distorted and inaccurate.
Phono preamps can be built into amplifiers and receivers, but many modern units no longer include this feature. In this case, an external phono preamp can be used to connect a turntable to a standard AUX input on a stereo. External phono preamps offer better shielding from interference and their own power supply, which eliminates the need to share with an electrically noisy power transformer on a hifi amplifier.
Choosing The Right Phono Input For Your Turntable
When it comes to choosing the right phono input for your turntable, there are a few factors to consider. First and foremost, you need to make sure that your turntable requires a phono input in the first place. If your turntable has a built-in preamp, you can connect it to any line-level input on your amplifier or receiver. However, if your turntable does not have a preamp, you will need to use a phono input or a separate phono preamp.
If your amplifier or receiver has a phono input, you can connect your turntable directly to it using an RCA cable. However, not all phono inputs are created equal. Some phono inputs are designed for moving magnet (MM) cartridges, while others are designed for moving coil (MC) cartridges. Make sure that the phono input on your amplifier or receiver is compatible with the type of cartridge on your turntable.
Another factor to consider is the quality of the phono input. Some amplifiers and receivers have higher quality phono inputs than others, which can make a big difference in the sound quality of your vinyl records. If you are serious about getting the best sound possible from your turntable, you may want to consider investing in a separate phono preamp that is specifically designed for high-end audio systems.
Troubleshooting Common Phono Input Issues
Despite the benefits of using a phono input, there can still be some common issues that arise when setting up and using a turntable. Here are some troubleshooting tips to help you diagnose and fix any problems you may encounter:
1. Check the connections: One of the most common issues with any audio system is loose or faulty connections. Make sure that all cables are securely plugged in and that there are no frayed wires or damaged connectors. If there are, replace the cables as necessary.
2. Clean the record and stylus: If you notice crackling or distortion while playing a record, it could be due to dust or debris on the record or stylus. Use a soft brush to gently clean both before playing.
3. Check the cartridge wiring: If you are experiencing intermittent crackling or distortion, it could be due to a short between the hot and ground on the right channel of your cartridge or anywhere in the wiring up to the phono input. This can be difficult to diagnose, but checking for loose connections or damaged wires can help.
4. Ensure correct turntable setup: Double-check that your turntable is set up correctly, including proper alignment of the cartridge and stylus, correct tracking force, and proper anti-skate settings.
5. Verify proper phono input usage: Make sure that you have plugged your turntable into an appropriate phono input or phono preamp. If your turntable does not have a built-in phono stage, you will need an external phono preamp or a receiver/amplifier with a phono input to amplify the signal correctly.
6. Check for input impedance mismatch: Moving coil cartridges produce a much smaller signal at a lower impedance level and require an additional gain stage at the phono preamp. They also need a much lower load impedance at the input stage. Some amplifiers or phono preamps will have a separate or switchable input stage for moving coil phono cartridges, so double-check that you are hooked up correctly for your cartridge type.
By following these troubleshooting tips, you can ensure that your turntable and phono input are working correctly and producing high-quality sound reproduction from your vinyl records.
