What is a Preamp or Phono Stage? Do I Need a Phono Preamp?

What is a phono preamp?

Preamps are a type of audio component that amplifies the signal generated by the phono cartridge of turntables. Because the cartridge produces a tiny electromagnetic signal as it reads the grooves, it needs multiple stages of “gain” (boost) before it’s loud enough to power speakers to create audible sound. The preamp provides this initial level of signal boosting, preparing it for the power amp, and is a vital component for vinyl playback.

The phono preamp boosts the signal from “phono” to what’s called “line level,” hence why some turntables have a phono/line switch on the back. “Line” is a louder type of signal to phono and meets the signal strength requirements of amps and speakers.

Many (but not all) turntables have a phono preamp built into them for convenience. Although, built-in phono preamps generally offer lower sound quality than external ones. Users often favor external preamps for their audio setup because they enhance the audio quality, such as the detail, depth, and stereo width (also known as “soundstage”). It also provides an extra layer of customization when building your vinyl music system.

Types of phono preamps

There are two main types of phono preamps:

• Solid-state preamps (modern audio components)
• Tube phono preamps (vintage-style circuitry with orange glowing bulbs).

Phono preamps also cater to specific types of turntable cartridges. (Read more on that here: What is a Turntable Cartridge?)

MM vs MC cartridges

In a nutshell: Moving Magnet (MM) and Moving Coil (MC) refer to two different cartridge types. An MC cartridge creates a weaker phono signal, so they need extra amplification to get them to the right level. Some preamps work with either cartridge type, although moving magnet cartridges are more common. Read more here: MM vs MC cartridges.

To understand exactly what a preamp is and why they are necessary, it’s good to have a basic understanding of the signal flow within a turntable sound system. Here’s how that goes:

1. The cartridge generates a low-level phono signal.
2. The preamp amplifies the phono signal to line level.
3. A power amplifier boosts the line signal to speaker level – enough to move the speaker cones.
4. The speaker cones are vibrated by the amplified line signal, creating an audible sound so you can hear music.

What is a phono stage?

This is just another term for a phono pre-amp. Because there are multiple ‘stages’ of amplification, it makes sense to call these types of preamp a phono stage. (Short for phono stage pre-amplifier). You simply plug a turntable into it, then plug it into the next piece of audio equipment.

What does a phono preamp do?

Getting started with an all-in-one record player or a wireless turntable and a Bluetooth speaker is easy for those new to the vinyl scene.

Preamps, on the other hand, are a whole other story.

For a stereo system to accept the signal from a turntable (or any other audio source, for that matter), a turntable preamp boosts the low output signal from the turntable to a higher level. This is the main function, although some preamps offer additional processing and EQ controls to color further and customize the incoming signal.

The most crucial thing to remember is that preamplifiers are needed to properly boost the record player’s outputs for the next amplification stage.

Generally, they have the purpose of increasing detail and sound stage. A preamp can unlock or hamper the quality of a high-end cartridge based on the quality of the components used. Based on the way they process the signal coming through, they affect sound quality to quite a large extent.

How does a phono preamp work?

There are no other components in a turntable signal chain that are capable of performing this specific task, especially relating to this particular stage of the signal path in audio systems.

It does more than simply make your system function more smoothly; it molds the audio quality of your turntable and guarantees that it is compatible with the rest of your system.

A turntable preamp boosts the output of a record player so that it may be received by an amplifier, which subsequently increases the volume of your speakers. The preamp adds a significant amount of amping to the signal.

In terms of electronic consumption, only the motors of a turntable use electricity; the stylus or cartridge uses none. For this reason, the preamp is needed to add extra current to the tiny signal created by the cartridge output.

When the stylus moves over the grooves of a vinyl record, it creates a signal. Electrical signals are then generated from this auditory signal. However, this is a very weak signal. It typically has a 4 mV output. Compared to a CD player or laptop signals, the signal is incredibly weak and requires extra amplification to get it to the same level. The output of a simple preamp is 300 mv.

To put it another way, the tiny signal of a turntable is only compatible with an amplifier if it is multiplied by 75-100 times.

The preamp, as you can see, has a significant influence on vinyl playing and the sound quality of your record player. Fortunately, a high-quality preamp won’t set you back several hundred dollars. You can pick up decent standalone preamps for less than $150.

Although they may not be as high-quality, the cheaper and less-expensive models on the market nevertheless perform well for casual listeners.

Due to the design of external preamps (such as a decoupled power supply), they often have a much cleaner signal-to-noise ratio than internal preamps. Astonishing playback quality and low noise levels characterize modern models, as well as less distortion and increased channel separation.

Do I need a phono preamp for my turntable?

This depends on a few factors – whether your turntable has a built-in preamp and whether your level of interest in vinyl deserves the advanced level of customization provided by using an external preamp.

Whilst many audiophiles like to use a separate preamp in their sound system, it’s not always necessary. Many modern turntables come with a built-in phono stage. However, these often have a high noise floor and O.K. sonic quality.

Also, many (if not most) turntables don’t have an internal preamp; in this case, you’ll need to buy a standalone unit to connect to the line inputs of your receiver.

Is there any way to tell whether your turntable has a built-in preamp?

This is generally pretty easy to find out, and there are three ways to do so:

1. Search for your turntable model online and check the specifications – It’s usually clearly stated there
2. Check the back of your turntable for a PHONO-LINE switch. If it has one, that means that 1) you do have a built-in preamp, and 2) you could bypass it if you wanted to buy a better external one.
3. You can also test: Connect your record player to your sound system or high-quality powered speakers. If the volume is very low, you’ll need an external preamp. (IMPORTANT: If your amp/stereo system has an input labeled phono, make sure you don’t feed it a line signal!)

The good news is that a phono stage doesn’t have to be an expensive high-end device. Many inexpensive turntables have one, whereas many more expensive versions don’t. The reasoning: If you’re willing to splash out on a turntable, you’re probably doing that for sound quality and therefore want to splash out on an external preamp too.

What is phono input?

This is a terminal connection designed to receive a phono signal. These typically connect to a preamp inside the receiver, which boosts the signal to line level, ready for the power amp to reproduce through speakers.

Line vs. phono: What’s the difference?

These are the two types of sound signals. Phono is a low-level, unamplified signal and needs to be fed into a preamp for boosting. When boosted, it becomes a line signal. CD players, phones, laptops, audio interfaces, and other electronic devices create a line signal.

A PHONO-LINE switch on the rear of turntables allows us to switch between the two output levels quickly. (These aren’t found on all models, and their presence indicates the inclusion of a built-in preamp).

Do I need a preamp if my receiver has a phono input?

They are not strictly necessary if your receiver includes a phono input. However, buying an extra good preamp can make a big difference in the quality of your home audio system.

Even if your record player is equipped with an inbuilt preamp, the same rules apply.

Even so, it’s not a bad idea to buy one. Built-in preamps (in both turntables and receivers) are often an afterthought and cut corners on components and quality, and are easily outshone by external models.

Built-in Phono Preamp vs External Preamp

Many turntables include a built-in preamp, which will be good enough for a casual listener, although they are often far from perfect.

There are two reasons to buy a phono preamplifier – even if your amp/turntable has one built-in.

1. Your cartridge’s output is too high or too low

The phono input on receivers is set to a standard (fixed) value to match the output levels of turntable cartridges. Similarly, the cartridge’s output is also set to a fixed value.

If your cart output is too “hot” (strong) for your input, the reproduced sound will be distorted, which is obviously not what you want.

An external preamplifier can overcome these issues. Most will allow you to adjust “gain” settings to compensate for weak/strong phono signals.

Also, if you use Moving Coil cartridges, generally, the built-in phono stages are not compatible. That’s because typical phono stages are designed to handle MM cartridges, which produce a stronger signal.

2. The original phono input is low quality

Just like turntables can have built-in phono preamps that are just OK, the same can be said for amplifiers/receivers. Their phono inputs can be made based on lower-quality components and do not perform very well.

If you are concerned about sound quality and don’t own a high-end receiver, buying a good external preamp can make a big difference. It does add extra cost to your setup, but why spend $500+ on a record player only to listen to it through a low-quality system?

How much should you spend on an external phono preamp?

An expensive preamp can make a large improvement to the overall audio quality of sound systems. Ultimately, the more you spend, the better the results are. Although, there’s no point in getting a preamp that far exceeds the quality of the other devices in your audio system. It also depends on your level of interest in audio fidelity.

If you want something that makes a noticeable difference over the built-in variety, I’d say go for something $100 and above. If you’re a budding audiophile, then $250+ is a good place to start.

If you just want something basic that gets the job done, then preamps around $50 are often enough to make an improvement to your audio system, especially over a built-in phono stage.