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How to Connect Preamp to Interface: A Step-by-Step Guide

Step By Step Guide On How to Connect Preamp to Interface

Have you spent countless nights polishing that specific bass note and are finally ready to start recording? Are you chasing after clear and accurate signals?

Whether you’re a self-certified music veteran or completely new to the world of recording, these instructions will carefully guide you and show you how to connect a preamp to an interface.

Table of Contents

Ways to Connect Preamp to Interface

Make sure that your set up (involving a pre amp and an audio interface) is ready before you continue reading the different processes you could pursue!

1. Audio Interface Line Inputs

Audio Interface Line Inputs

An audio interface with line level inputs can receive pre-amplified signals. Converters process these signals IMMEDIATELY for them to go straight to your DAW.

Before you continue, make sure to check if your preamp Line-out is XLR or TRS so that you know which cables to use.

  • XLR cable: carries two copies of the signal; used for MICS
  • TRS cable: sends one copy of the signal to DAW; used for INSTRUMENTS

If it has a TRS port, you can plug one end of a TRS cable into the Line-out port and plug the other end into the Line input on the audio interface.

If it has an XLR input, look for XLR cables that can go from XLR female to male TRS jacks.

Take note that line input on interfaces is usually at unity gain, which means that it doesn’t affect the dB level of the signal at all.

Check Mic Level and Line Level

These levels are very different from each other.

  • The mic level usually falls between -60 and -40 dBu.
  • The line level is approximately 1 volt or 1,000 times stronger than the former.

Make sure that you connect your device to the correct input because if you connect mics to line-level inputs, the connection would be too weak, and there would be no effect.

If you connect your line level to the mic level, expect a loud and distorted sound.

2. Use the Audio Interface’s ADAT Input

Use the Audio Interface_s ADAT Input

ADAT ports are usually added to interfaces to increase the number of potential interface inputs. This is definitely an advantage if you’re looking to save money!

If both your preamp and your interface have an ADAT input, you can directly connect the former’s ADAT output to the latter’s ADAT input with an ADAT cable.

The digital signal sent out would be translated (not converted) by your interface and sent directly to your DAW.

3. Proper Gain Staging with Combo Jack Input

Proper Gain Staging with Combo Jack Input

Interfaces often come with combo jacks. Like the combo packs you see in groceries, combo jacks contain 2 connectors in 1; the outer is an XLR jack, and the middle part is a TRS jack.

Use the XLR port for mics and the TRS port for line sources or instruments.

Turn the gain level of your interface to zero, and connect the Line-out of your pre amp to the combo jack input of your interface with a TRS or XLR cable.

Do take note that this may not be the best option to pursue if you want to bypass the interface’s pre amp, since the signal goes directly through the interface’s circuit.

If you like this option, you may try turning down the audio interference gain to lessen its effect on the signal.

Microphone Preamp vs. Audio Interface

Microphone Preamp vs. Audio Interface

These two terms are quite distinguishable from each other but are BOTH important components of the recording process.

Are you aiming to amplify low-level signals?

This is the primary function of a mic pre amp, not the interface, as its main purpose is to give you an easier time hearing low sound signals.

Looking for a way to transfer your music recordings to your laptop?

An external audio interface (such as the PreSonus audiobox USB interface or the Focusrite Scarlett 2i2) can help with that, as it helps convert your recording into a digital music format.

What Is a Microphone Preamp?

Now that you’re aware of the basic functions, let’s get a little bit more technical.  Imagine taking the low output from a device and amplifying it to reach a higher level.

Why is this important?

A line level signal determines the strength of various audio signals that result from audio devices.

A good preamp is needed to create a clear, accurate, and BALANCED signal chain.

Why You Should Get a Mic Preamp

Still unsure if you should get a microphone pre amp? Take note of the following benefits to determine if they align with your needs!

  • Provides clean and accurate signals
  • Helps remove background noise
  • Makes your music richer by lending color and flavor

Since there is a wide range of pre amps, you get more than enough room to experiment and determine the BEST possible permutations for certain vocals and instruments!

Different Types of Microphone Preamps

Did you know that different types of mic preamps can either help contribute richer and colorful audio? (i.e., onboard pre amp) 

These mics ensure you have ACCURATELY translated original audio!

Also, keep in mind the importance of gain because some devices allow you to experiment with gain settings while others don’t.

Keeping the vision of your final output in mind, you can look through these examples to help you decide!

Tube Preamps

Tube Preamps

Do you want to lend a sense of warmth to your music? Tube preamps might be the way to go! They consist of tubes that mildly distort sounds.

Don’t worry, though, because they still sound appealing!

In the case of tube preamps, the distortion often results in second-order harmonics, which produces depth and warmth.

However, this type of preamp might be a disadvantage for percussion sounds as it often affects and lowers sounds with high Hz.

Solid-State Preamps

Solid-State Preamps

A solid state is one of the three fundamental phases of matter.

According to science, a solid-state preamp focuses on creating minimal distortion levels with a high level of gain.

Transistors operate more consistently as enough gain is applied, ensuring higher gain levels without distortion.

Solid-state preamps also result in tones ranging from vintage to modern, which gives you a wide array of effects!

However, a definite drawback to this pre amp is that the sound coming from certain instruments can be harsh at times, resulting in odd harmonics.

Digital Preamps

Digital Preamps

This type of pre amp successfully converts analog signals to digital signals while adding their sonic signature during the processing period.

It’s possible to bypass the conversion process of an audio interface.

Many individuals consider digital preamps as a digital audio interface, but they were primarily designed as preamps.

The digital conversion of audio signals was just a CONVENIENT benefit!



Do I Need a Microphone Preamp With an Audio Interface?

Yes! You would need both a pre amp and an audio interface to record successfully.

MOST audio interfaces already have built-in preamps, but there are certain cases where purchasing external preamps is needed to improve your sound quality.

If I Have a Mixer, Is a Mic Preamp Still Necessary?

While almost all mixers have a pre amp, the quality is not as strong as an external pre amp because the mixer only combines music tracks.

Having a pre amp is ESSENTIAL for amplifying low audio signals and producing clear outputs.

Why Do Most Budget Audio Interfaces Have a Preamp?

Most budget interfaces have a pre amp which helps them directly convert amplified signals and translate them into digital music.

However, the output quality is often weaker than the output quality of an external pre amp.

Are There Audio Interfaces Without Preamp?

Yes, there are some audio interfaces without a preamp.

Some people prefer having their music be as accurate as possible to the original recording without the interference of an interface preamp,

On the other hand, others prefer using an external pre amp for better quality.

What Is Phantom Power?

Did you immediately start thinking of ghosts? Unlike the phantom power you see in horror films, the phantom power, in this case, is a DC voltage.

Its positive side prioritizes both signal pins.

Generally, they’re required for condenser mics, and you should deactivate them on ribbon mics to be safe!

Many mics have it, but make sure to connect them before turning on the phantom power! Doing so keeps your microphone device safe from any potential damage.



If you’re aiming to produce pro audio, a pre amp and an audio interface set up will give you a successful home recording session!

Don’t be afraid to EXPERIMENT with the various settings of your pre amp and interface to get the combination that suits your music the best.

About the author


After becoming obsessed with the beats that were the soundtrack to his youth, Nick became a student of hip hop, digging for vinyl records, looking for the perfect break. Before he got his hands on an MPC sampler, he would mash these records, beats, and breaks into mixtapes and live DJ sets.