Preamp Vs Amp: What’s The Difference?

Whether you’re a pro or just getting started with sound systems, it’s tough to know if you need a preamp or not. It sounds like a crucial piece of equipment, but if you can’t invest in both, which one should you get? When you’re considering a preamp vs amp, you need to know what each item does and what purpose it serves in your stereo system.

What Does a Guitar Preamp Do?

A preamp boosts weak signals to line level. That means it improves the sound levels of softer instruments, like microphones and electric keyboards, up to the standard level needed for an amplifier to pick up the sound. The amplifier then further boosts the sound, both in terms of volume and output options you can use to alter the sound.

Preamps themselves don’t change the sound quality. You can’t adjust bass, treble, and other audio levels with a preamp. It’s a device that takes the input and kicks it up a few notches before passing the sound along to an amplifier. This lack of audio engineering options can be a good thing because it keeps your sound pure. But if you’re looking for effects, a preamp isn’t going to give it to you.

Considering that preamps can’t change sound quality, you’ll want to make sure you have quality instruments before even hooking up a preamp. A subpar microphone hooked to the best preamp is still going to sound like a bad microphone. A preamp only amplifies the sound it’s given.

What does a guitar preamp do? The easiest way to remember is to break down the name itself: a preamp goes before the amp to increase a microphone or instrument’s audio level to the baseline standard.

What Does a Guitar Amp Do?

Some audio technology contains built-in amplifiers that work to a certain degree. Still, if you’re considering preamp vs amp, you’re probably thinking of independent amps that factor into a chain of technology to boost the volume and sound quality.

While a preamp boosts the sound and sends it through an amplifier, an amp improves sound so you can hear it clearly through speakers. The main purpose is to increase sound to a level that allows the connected speakers to reproduce it at an ideal volume.

An amp not only boosts the line signal, like the preamp does, but it can also do many other things. An amp can mute signals, add filters to audio signals, change the channel balance, and more. After the sound is input through an amp and you change the effects, the audio is output via speakers.

Difference Between Preamp and Amp

You can’t use a preamp as an amp, but it’s still a piece of technology you might want to consider adding to your lineup. The two components do similar jobs but fill different needs within your broader speaker system.

The difference between preamp and amp isn’t limited to what features they offer and how you plan to use them. While a preamp isn’t a necessary piece of technology in your system, it can boost your audio quality to the degree that makes it worth the investment. 

Preamps are most useful for improving microphone audio levels, whether it’s for a singer, a karaoke party, or if you position mics closer to certain instruments while you’re performing. 

Let’s further break down preamp vs amp, so you know the pros, cons, and best uses of each.

Preamp

The preamp boosts low signals to line level, which is the base level of a sound to be picked up by an amplifier. An example of this is a microphone, which has a weak level on its own. The microphone’s sound gets a boost when you connect it to a preamp. The amp further boosts the microphone’s sound so you can hear it through the speakers.

Pros

  • Boosts weak signals up to line level
  • Is a supplementary device for a speaker system
  • Uses less power than an amp

Cons

  • Cannot be used without an amp
  • Doesn’t offer any extra audio options

Best Used For

Musicians who want to level up their sound before it even reaches the amps will want to use a preamp. Karaoke systems benefit from using a preamp, as do many musicians who mix their tracks. You can’t use a preamp directly with speakers, so if you want to invest in a preamp, make sure you have a compatible amp to go with it.

Amp

After the preamp boosts a microphone’s levels, the amplifier strengthens the sound even more. If you don’t use an amplifier, the audio signals will be distorted and have uneven sound levels, resulting in poor quality audio. Amps are connected to speakers to give the sound even more volume.

Pros

  • Has many functions for improving audio output
  • Much more powerful than a preamp
  • Connects to speakers for a well-rounded sound system

Cons

  • Is a fundamental device for a speaker system
  • Uses a lot of power and produces heat

Best Used For

Musicians who want to boost their instrument’s strength as the audio goes into the speakers will want to invest in an amp. You can plug most instruments directly into an amp, so you’ll only need to buy this one piece of equipment.

How to Use a Preamp

To use a preamp in your sound system, make sure you hook it up early in the chain. Connect the preamp directly to the instrument, if possible. For example, for singing and karaoke, plug the microphone into the preamp so the preamp will boost the microphone’s audio quality.

If you hook up mics on stands and position them next to other instruments, you’ll still want to plug the microphone into the preamp. Make sure you have enough cord to position the stand next to the instrument while still connecting to the preamp, which in turn connects to an amp.

Once your microphone or other instrument is plugged directly into the preamp, you’ll want to connect it to the amp. Make sure you can put some distance between the preamp and the amp because these two devices can communicate and cause distortion or static if they’re too close.

Since preamps are made to be connected to amplifiers, you won’t have any trouble linking the two. The amp’s audio inputs are clearly labeled so you can use the cable, which is typically an RCA or XLR cable, to match the preamp output with the amp input.

Every time a preamp and amp are added into your sound system’s chain of command, you’ll be introducing what is called a “gain stage.” A gain stage boosts the audio’s volume to a point where it can be used by the next device. For example, as you’ve learned here, a preamp boosts a microphone’s volume enough so it can be picked up by an amplifier.

Something you want to consider is that each gain stage adds noise to the signal. If you’re trying to add too much technology between the instrument and the amplifier, you might get some static or noise that interferes with the true sound you want.

What Can Connect to a Preamp?

It’s essential to know what can connect to a preamp when you’re trying to decide if you need to invest in a preamp vs amp.

Instruments

When you’re using a preamp with another instrument, like keyboards, you can still plug that instrument directly into the preamp. Preamps are popularly used with acoustic guitars because they keep the instrument’s sound clean without adding any effects that change its impact.

If you’re using a standard preamp with an electric or bass guitar, you might get some distortion, which can be ideal if that’s the sound you’re going for. You might want to play around with how each instrument sounds with a preamp before hitting record.

Preamp Pedals

You can link preamp pedals into your sound chain. Bass preamp pedals are a great way to get a preamp’s benefits with some additional functions to level up your guitar’s sounds. Preamp pedals have a variety of EQ options so you can customize your instrument’s bass, treble, and audio levels.

Preamp pedals connect directly to your guitar before feeding into the amp, just like a standard preamp would do. The preamp pedal’s options let you get your sound exactly right before sending the audio to the amp, which boosts the signal’s volume. Therefore, using a preamp pedal is a good idea if you want to change your sound instead of just turning it up.

Audio Receivers

People typically use audio receivers in home theaters and stereo systems. The devices can receive sound from various sources depending on what you connect, like DVD or Blu-ray players, TVs, record players, radio frequencies, MP3 players, and more.

On their own, audio receivers can’t play loud enough to be easily heard and enjoyed. If you’re trying to set up a killer home theater system, you’ll want a preamp for your audio receiver. You’ll directly link the preamp to the audio receiver, just like when connecting it to a microphone.

After you get the audio receiver and preamp set up, you can then connect the preamp to the rest of your home theater speaker system for the best results.

People Also Ask

If you’re still a little uncertain about needing a preamp vs amp, you’re not alone. Here are a few questions people ask after learning about this equipment. 

Do You Need a Preamp and an Amp?

If you have a preamp, yes, you’ll have to connect it to an amp. A preamp only boosts audio input enough to send it on to an amplifier for further improvement.

If you only have an amplifier, you can use it without a preamp. 

If you’re using a microphone, you’ll need both a preamp and an amp. A microphone’s audio output isn’t strong enough to input directly into an amp. It requires a preamp to boost the sound levels enough to then connect to an amp.

Does a Preamp Improve Sound Quality?

No. A preamp only takes the sound given to it and boosts it up to the base level needed for amplifier input. Preamps don’t have options to change bass, treble, or other audio levels.

What Should You Look for in a Preamp?

You only need a basic preamp to improve your sound levels, so you don’t need to feel overwhelmed by all the technical specifications. Something you might want to play around with is how many channels you want your preamp to have. They typically come in one-, two-, and eight-channel options.

You’ll want to look for a preamp that has:

  • Solid-state tube models for the cleanest sound
  • Maximum gain that is compatible with your microphone
  • Input/output channels that can connect with the technology you already have

If you have any other questions regarding the difference between preamp and amp, leave a comment, and we’ll get back to you.

The Bottom Line

When weighing preamp vs amp, the bottom line is that, while a preamp isn’t effective without an amp, it’s a supplementary piece of technology that isn’t required for your sound system. You don’t need a preamp unless you want to boost weak signals to line level, and your current speaker system doesn’t offer a direct connection. 

Some audio interfaces have hookups for microphones and other instruments with weak signals, so you can plug directly into that. If you’re using speakers to create a robust home theater for viewing TV and movies, you won’t need a preamp.



Michael Southard

Michael is a multi-instrumentalist with extensive knowledge of audio production. He loves trying new gear to discover gems to create unique sound.