Turntable technology has been around for years since its inception in the late 1800s and has managed to survive the ever-evolving sound technology world.
Turntables are still used today by a wide range of music lovers for audio playback in the sound and stereo system. However, there is one vital component of a turntable that most vinyl lovers tend to overlook or at least don’t know much about, a phono preamp or a phono stage.
A phono preamp, RIAA preamp, or a phono stage is a piece of electronic turntable technology that takes low-voltage phono signal and steps them up to line-level signals. These line-level signals can then be sent from a phono preamplifier to an amplifier where further amplification takes place before they are transmitted to a speaker driver for playback.
The phono signal has to be amplified in the phono stage circuit at is a very low signal that is not enough for proper sound reproduction.
But this is not the only task performed by this preamplifier as it also applies an RIAA equalization curve to the signal for a flatter frequency response, better fidelity, and better tonal characteristics making the audio playback as lifelike as possible.
A phono preamp can be found within a turntable, in a stereo amplifier, a stereo receiver/integrated amp, or stereo powered speakers.
But how does this electronic component work? How is it used? And is it even worth the investment? These are some of the questions and more that I will help you answer for you to make a more informed buying decision.
Contents and Quick Navigation
How does a phono preamp/phono stage work?
To better understand how a phono stage works we need to go to the starting point where you insert your vinyl record and reset the arm on your turntable to the starting point. This is where the magic begins.
Once the record starts spinning, the turntable’s needle scrapes its surface for grooves which generate vibrations on the needle (stylus) depending on the recorded audio. These vibrations are then transmitted through wires on the arm to a cartridge on the arm’s diaphragm.
At the cartridge, which can be a Moving Coil (MC) or Moving Magnet (MM) cartridge, these vibrations are turned into an electrical signal with the help of a magnetic field.
The problem is that the signal generated is very weak usually around 5 millivolts or 0.005 Volts on average on an MM turntable and 0.5 milliVolts/0.0005 volts on average on an MC turntable. These signals need to be correctly amplified to a line level (around 300 mV or 0.3 V) and this is where a phono preamp comes in.
The Preamp can either be a Moving Coil or Moving Magnet phono stage that takes these weak signals and puts them through a circuit where they are amplified to 0.316 volts which is the same level as the signal produced by a CD player.
But this is not the only thing that the phono stage does. On the circuitry, something interesting happens, an RIAA correction curve is applied using a filter that boosts the low-end frequencies, reduces the intensity of the high-end frequencies, and reduces noise for better fidelity, higher sound accuracy, and higher sound quality in general.
What is an RIAA curve?
This is a complex topic that requires an article of its own but for this article, I will make it as brief and simple as possible.
An RIAA equalization curve is a vinyl EQ standard that was established by the Recording Industry Association of America to reduce groove damage, improve recording times, and for higher sound quality within the record.
Essentially, this is accomplished by boosting the high frequencies which require smaller grooves, and cutting down the volume of the low frequencies to be fitted in smaller grooves within the vinyl records.
The opposite happens on the RIAA filter found in a phono preamp where the signals are corrected by boosting the low frequencies and the high frequencies are cut. Record noises such as clicks and hisses are also reduced for richer audio signals with better clarity.
Integrated Vs external phono stage
If you have a turntable or are planning to upgrade your sound system, it is important to know that a phono stage can be built-in within some of the equipment.
A phono preamp can be integrated within a receiver, turntable, powered stereo speakers, or even as a standalone separate entity.
Separate phono preamps are recommended due to their superior sound quality but even an integrated phono stage can do the job quite well.
A turntable with a built-in phono stage usually has a line-level output but you can also tell if it is integrated within the turntable by looking at the user manual, online manual, or by connecting it to your system and paying attention to the volume level of the sound produced. Usually, the pressure level will be high enough and the sound will be well-balanced if the RIAA preamp is built-in.
Not many receivers, power amplifiers, or integrated amplifiers have a phono stage but if yours has one, there will be an input port at the back of the device labeled as “PHONO”.
Some powered stereo speakers also have an integrated phono stage. These speakers are made with great attention to details to reproduce high fidelity vinyl playbacks.
A built-in phono stage will be convenient for an easy plug and play situation but will not provide you with the superior audio quality and control over your audio as an external RIAA preamplifier. The sonic consistencies and sound characteristics on a high-quality external phono preamp are significantly better, especially at a higher gain.
What is the difference between a phono stage and a phono preamp?
Phono stage and phono preamp are 2 terms that are often used interchangeably. And although they essentially do and mean the same thing, they are different.
A phono preamp or a phono preamplifier is can be built-in or external but a phono stage is usually built-in whether it is a stereo receiver, a phonograph, a stereo amplifier of powered speakers.
Choosing a Phono preamp
Before spending your hard-earned money on a high-quality phono stage there are considerations to make for a worthy investment (this is an investment that should last you several years and up to a decade or two with proper care).
The most important buying consideration is the types of turntable you have or plan to add to your system.
As I pointed earlier, turntables are categorized mainly on whether they are made of a moving magnet or a moving coil. Usually, the phonograph should be paired with the right phono preamp which can either be an MM preamp or an MC preamp but some phono stages can be both and come with a switch or different phono inputs.
A moving coil preamp has better performance and lower RF interference when compared to a moving magnet preamp but is usually costlier. But as I said, you will need to pair your devices correctly.
The quality of this device is also of the utmost importance as they are designed and built differently. A lot of work and money goes into a good build-quality meaning that you will spend more on the same but hum and other noises that are common in turntable are significantly reduced to a bare minimum.
With that said, you should keep in mind that excellent sound quality will not be limited to the phono stage alone. All the other components such as the amplifier and speakers need to be equally as good. The audio reproduction is only as good as the weakest link in your sound system
How much does a Phono preamplifier cost?
The cost of a phono preamp can range from as low as $50 to as high as $15,000 for high end “audiophile” devices. $50 will get you an entry-level device that may not be any good and $15,000 will be overkill, at least for the average consumer.
But as with everything in the electronics consumer market, there is always the middle ground or higher middle ground.
A good starting point for a great phono stage would be the $200 to $300 price range. This will get you a high-quality preamp that should be full of life something that cheaper devices may lack. However, if your budget allows it, you can always get into the $1000 price range to improve the magic with great precision and equalization.
How to set up a phono stage
A phono preamp will need to be connected to a power amplifier, powered speakers, or a receiver. This can be done either wireless through Bluetooth or using line-level cables such as Aux or RCA cables.
A wireless connection should be pretty straightforward as it will involve pairing your devices.
A wired connection, on the other hand, should be done from the line-level output (Line Out) on the phono to the line-level input (line-in or IN) on the next device. Ensure that you connect the left output from the preamp to the left input on the receiver/integrated/amp/speakers and the right output to the right input.
Do not connect your cable to video inputs, any output, preout, zone section, or phono input on the receiver if it is available.
If your phonograph has a phono output but you bought a better external phono stage, you will need to look for a switch or toggle on the phonograph to bypass its internal phono stage. This will prevent distortion of the sound, overload, and hum due to interference.
The placement and cable runs will also need to be done carefully. Do not place your phono stage on a receiver, an integrated, a power amplifier, or speaker. Basically, you will want to keep the phono preamp away from anything with a magnetic or anything that draws large amounts of power as this can introduce annoying noises and hum to your system due to electromagnetic interference.
Your power cables will also need to run separately from the phono cable runs due to the same. If any cable needs to run across any of the cables to and from your preamp, ensure that they cross each other at a 90° angle.
You want to reduce interference and noise as much as possible as the power amplifier can also pick up and amplify them to your speakers.
Using a single surge protector or power conditioner to connect all your devices will also reduce noise but will also help protect your equipment from power surges and brownouts. The turntable should also be well ground for a great sounding system.
Is a phono preamp worth it?
A phono preamp is a worthy investment and can make a great difference if you make a wise purchasing decision. It can also greatly improve sound quality even with devices with built-in stages.
This is a piece of equipment that you should select with more care than other parts of your sound system whether you are building it from the ground up or simply upgrading an existing system. Phono stages are delicate devices that are prone to noise and, therefore, making the right buying choice is of the utmost importance.