Preamp vs. Interface [Definitive Guide]


  • 8/27/19.
  • 5/4/20. Thank You to Tim for pointing out a mistake/typo in the article!!

2,015-word post, approx. 4 min. read

Hi friend and Welcome!

What is the difference between a Preamp vs. Interface? Glad you asked. It’s a super important question in determining which gear you decide to buy for your home studio! Before we get started though…

Grab a snack, sit back and relax because…

You’ve come to the right place!!

What I will bring you in this article

  1. Introduction
  2. What is a Preamp?
  3. Does a Preamp Improve Sound?
  4. How to hook up an audio interface to an external preamp?
  5. Do you need a mic preamp if you have an audio interface?
  6. Does it matter what Audio Interface I use?
  7. Focusrite Scarlett 2i2
  8. What do Audio Interfaces do?
  9. Top Recommendation/Final Word

Now without further ado, let’s get rolling!


You may have been shopping around for an audio interface when the term “Preamp” came up. Now you’re wondering what the difference is, and do I need both or just one? Do interfaces come with built-in preamps?

All of these are great questions that I’ve had to deal with in buying gear myself. It can be confusing and frustrating when starting out. There are so many options available to us and I’ve been overwhelmed on more than one occasion. Today I’ll make it crystal clear!

What is a Preamp?

The purpose of a preamp is to amplify the low-level signal of your microphone, to a line-level signal. Because microphones on their own operate like Charlie Chaplin (aka quiet asf), the gain must be used in order to amplify them to a listenable level.

From Neumann’s article on Why Do I Need A Preamp?

Microphone signals are usually way below the nominal operating level, so a lot of gain is required, usually around 30-60 dB, sometimes even more. Guitars and basses donโ€™t require quite as much gain, but often around 20-30 dB. Even line sources such as synthesizers may require some amplification to match studio level, because there are various standards. The old standard for home audio and semiprofessional devices is (or was) -10 dBV while professional devices operate at +4 dBu (due to different voltage references, the difference is not 14 dB but roughly 12 dB). Today, even inexpensive home studio gear is usually designed for a nominal level of +4 dBu, but electronic instruments still often work at -10 dBV or thereabouts. Nuemann

With that said, an Audio Interface usually provides built-in preamps, allowing you to bypass the headache of having to connect the two (it’s not that hard, we’ll discuss it in a sec).

Does a Preamp Improve Sound?

There are a few different reasons why you may want a preamp in addition to an audio interface.

  • Sound Enhancement. This is a stand-alone unit with no direct computer connection. External preamps are often used to enhance vocals. They will change and alter the sound (color it if you will). External preamps have their own sound and have the ability to add a lot of flavor to your recordings via different tones, colorization, etc.
  • More Gain. Another benefit of having a separate preamp is that it will provide more gain. Audio Interfaces rarely provide more than 60dB, but some mics may require more. A ribbon mic for instance would require more like 70dB or more, so it’s something to keep in mind. That said, you’ll be fine with most entry to mid-level condensers paired with a good interface.
  • Better Components. The components in an external preamp are also usually of higher quality, and the power isn’t shared with other components. It isn’t night and day but does make a difference in the grand scheme. Once your ear starts to develop more, you’ll notice these small nuances in sound that can really make or break a recording.

How to hook up an audio interface to an external preamp?

A great question! There are really just 2 steps:

  1. Plug your microphone (using XLR cable) into the preamp’s mic input.
  2. Run a 1/4 inch cable (TRS), from the output of the external preamp, into an available line input on your audio interface.

There are a couple of important reasons why it should be done this way:

  1. By using the outputs on the back, you’re bypassing the built-in preamps of the interface.
  2. If you try to connect the preamp to the front (i.e. front-panel mic/instrument/line input) you’ll only end up with a myriad of issues including but not limited to: weaker signal, a higher level of noise, ugly audio artifacts, etc. You could also damage the inputs on the front of the preamp, or the preamp itself!

A couple of final notes:

  • Since you’re using an external preamp to bring the mic signal to line level, you don’t need the gain on the audio interface anymore.
  • Turn the interface gain knob all the way down.
  • Adjust the gain on the external preamp from now on if you need more.

Do you need a mic preamp if you have an audio interface?

Not necessarily. If you’re just starting out, an affordable audio interface like the Focusrite Scarlett 2i2 will most certainly do the trick. It has built-in preamps, so you’re sort of killing 2 birds with one stone.

Are the internal preamps of an audio interface as good as a separate one? It depends.

For the entry-level stuff, no. But once you start getting into some of the higher-priced gear, they may be. It’s hard to say.

Sean Divine made a great video on why this stuff is important, and if you may or may not need a separate Preamp. Be sure to subscribe to his channel!

Does it matter what audio interface I use?

Sean would actually say yes. In the video, he talks about how he’s owned a lot of different interfaces over the years and that the quality of the conversion does vary.

For me?

I’ve only had experience with 2 interfaces, the 2i2, and the M-Audio Fast Track Pro. The Fast Track Pro was pretty bad, while the 2i2 became a staple in my studio for about 5 years before I sold it recently. The reason for this is 2 fold:

  1. I desperately needed the money.
  2. After I upgraded laptops and started using Windows 10, I got a blue screen and said NOPE! It only took 1 to realize the culprit. Research indicates the 1st gen is compatible with Windows 10, but it’s hit and miss. Some people have issues and others don’t. I unfortunately did so I got rid of it. I’ll probably end up getting the 3rd generation 2i2 or Solo at some point though. More on that at the end!

Focusrite Scarlett 2i2

Chillin’ in-studio before I sold him ๐Ÿ™

For most people, a 2i2 or something similar will be perfect.

They’re convenient, will work with a bunch of different microphones, and come with USB capability. The Scarlett 2i2 is a good example. It works like a charm and is really easy to set up while also providing you an array of options.

  • You can hook it up to active studio monitors. What are Studio Monitors?
  • It uses 48v phantom power for any microphone I may be using. Before I sold it, I had been using it with the fantastic entry-level AT2020 and Samson C01. Learn more: Audio Technica AT2020 condenser microphone review!
  • You can plug a headphone in via the 1/4″ jack on the front and essentially use it as a headphone amp. Don’t rely on it for real power-hungry headphones or planar magnetics though. What is a Planar Magnetic Driver?
  • You can record an instrument with it via the combo XLR/TRS jack on the front as well.

It’s important to understand that an audio interface is the most important piece of gear in your studio. It’s essentially the link between you and your PC when you’re doing any sort of recording, playback, etc. with regard to mixing, monitoring, and everything else that comes with recording and producing.

What does an Audio Interface Do?

What does an audio interface do?
What does an audio interface do?

Glad you asked!

An Audio Interface is essentially a DAC. It provides a Digital to Analog conversion, converting the digital 1’s and 0’s that your computer understands, into the analog sound that you understand. This is most prominent with something like a Headphone Amp/DAC, where your computer is converting the digital recreation of the song into the sound your brain processes as sweet, sweet music.

This process also works in reverse. When you speak, rap, or sing into your microphone (analog), it gets sent across the motherboard of your computer, is processed, and then the recording is played back digitally for your ears. This conversion happens in less than a second!

The AT2020 is a great entry-level condenser that pairs well with a Scarlett Solo or 2i2.

To recap what a Preamp does?

Preamps just boost the signal on your microphone to a listenable level (called line level). That’s it!

Just think of it as a giant volume knob turned all the way up. The great news about audio interfaces is that the preamps used are clean and clear, and will do a fine job replaying back the recording at a loud enough level. If you plan on using an interface, you can also tweak the sound in a different way (separate from the stand-alone preamp mentioned above).

Channel Strip/Processor

This could mean using different mics, experimenting with mic placement, or using plugins that add different effects to the sound. A great example of an effects rack (or channel strip) that’s simple and effective is the DBX 286s. This baby allows you to edit the sound of your voice essentially in real-time, by providing features like an on-board Compressor, De-Esser, Enhancer, and Expander/Gate. It’s great for folks who are more hands-on.

In the above video, Sean was using an Aphex Channel.

Built-in preamps that come with interfaces really get a bad time of it. In reality, there’s nothing wrong with them. In fact, they are really the way to go in my opinion when starting out. They work perfectly in many small bedroom studio setups or otherwise, and ooze quality. Engineers 30 years ago would have killed to have the kind of equipment we spoiled producers have these days!

Down the road when you’ve got more experience under your belt, you can always add more pieces (like a preamp) and expand your sound capabilities.

Recommendations and Final Word

If you’re just starting out, I would go with an audio interface that has built-in mic preamps. As mentioned before, I used the 1st generation Scarlett 2i2 in my studio from 2014 – 2019 and loved every second of it. I never felt a need to upgrade!

Focusrite has since come out with their 3rd generation line, and when I’m in the market for another interface I’ll surely be picking one up. The Solo now utilizes balanced line outs (like the 2i2) instead of RCA this time around, has better sonics, lower latency, and enhanced ease of use. What is latency?

The new “air” feature utilizes the same technology apparent in their top of the line preamps, so you’ll be getting pristine quality and more headroom with various different mics (Ribbon Mics, etc.) Remember how I said before that was one of the main reasons to purchase a separate preamp? You may not even need to do that now.


Well, that’s about it for today friend. I really hope you have a clear idea of the Preamp vs. Interface and came away with some newfound knowledge!

Are you more inclined to purchase an audio interface or Preamp after this discussion? Both? Neither? Let me know!

Questions? Comments? Did I get something wrong or leave anything out? Leave a comment down below or contact me! I would love to hear from you..

All the best and God bless,





Be sure to check out my Reviews and Resources page for more helpful and informative articles!


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