Mic Preamps and Why They Are Important Artwork

My Take on Music Recording with Doug Fearn

Doug Fearn draws on his 50+ years as a recording engineer, record producer, studio owner, and pro audio equipment designer to explain the art and science of recording for the audiophile, music lover, and people in the music recording industry.

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My Take on Music Recording with Doug Fearn

Mic Preamps and Why They Are Important

August 13, 2026 • Doug Fearn

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Do microphone preamps make a difference in a recording? They certainly do for me. In this episode, I discuss why preamp quality is important, and the reason why different mic preamps sound different.

You might think that these differences are only detectable by engineers with “golden ears,” working with top-notch equipment. How could that have any impact on the average listener? I argue that it does make a difference, and improved sound helps everyone be more successful.

Here are links referenced in this episode:

Doug Fearn and Corrie Lynn Green talk about the making of her album, “Day 4 of living on the Edge.”

https://youtu.be/9rv0m94nq8w?si=Z0mawTYiKCX1PohD

Why Vacuum Tubes Sound Better for Audio:

https://www.buzzsprout.com/942952/episodes/4721579

Gain Staging:

https://www.buzzsprout.com/942952/episodes/19067208

Mic Preamp Design:

https://www.buzzsprout.com/942952/episodes/4998686

Listening

https://www.buzzsprout.com/942952/episodes/11165606

Why Different Gear sounds different:

https://www.buzzsprout.com/942952/episodes/11564815

email: dwfearn@dwfearn.com
www.youtube.com/c/DWFearn
https://dwfearn.com/

121 Mic Preamps and Why They are Important August 13, 2026

I’m Doug Fearn and this is My Take on Music Recording

Before I launch into the topic of this episode, I would like to tell you about a video I recently produced with singer-songwriter Corrie Lynn Green. It is mostly to promote her most recent album release, “Day 4 of Living on the Edge.” We talk about Corrie’s path to the music she writes and performs today. We talk about all the musicians that play on her records, and we discuss each song on the album. This is aimed at her fans, so there isn’t a lot of technical detail. But there is enough of that that I think some of you would find it interesting. There is B-roll video of sessions, mostly during the arrangement stage, not during the actual recording. There are sections where I talk about how I went about recording some of the more challenging songs.

It’s long, almost an hour and a half, but it’s divided into easy to access sections, so you can jump directly to any part you find interesting. I hope you find it interesting and I hope it gives you some ideas that you could apply to your sessions. The link is the first one in description below. Let me know what you think.

Now let’s talk about mic preamps.

Every recording that uses microphones, or a DI box, needs a mic preamp. The purpose of the mic preamp is to boost the very low level coming out of a microphone to the +4dBm line level required by the rest of our recording equipment.

Seems simple, but like most things in recording, there’s a lot more to it than just providing 40 to 70dB of gain.

Every preamp design has its own sound, although many of them are similar.

I was dissatisfied with any of the mic preamps I had available to me, and that led to the design of the D.W. Fearn VT-2. It provided the sound I wanted, true to the sound of music.

But let’s back up and look at the big picture.

All preamps do the basic job of boosting the level. And superficially, most of them sound pretty good. At least they do on first listen. Some people hear defects in the sound instantly. Other times, it might require listening to the same recording multiple times.

With some preamps the differences only become apparent when you listen to the music over a period of time. How long? Well, certainly over the course of a session. Sometimes even over the length of the song. Some mic preamps may sound good at first but by the end of the song, you begin to notice things that get on your nerves. It’s difficult to describe. Maybe the instrument or voice doesn’t quite sound “real.” Or there might be something irritating about the sound. Some people are more sensitive to this than others.

And you don’t have to be a recording engineer or musician to hear this. Some music consumers react negatively to the sound of some songs. That can be caused by many things, but the equipment used to record the performance can be one of them, especially for vocals.

Does that matter? For some music, no, it doesn’t make much difference. For some listeners it may not matter. They either like the song or they don’t. But if they enjoy the song, they probably want to hear it again, either right away or in the near future. They may add it to their playlist.

Eventually, they may edit their playlist to eliminate some songs that have lost their appeal. That might be for a variety of reasons, but it could be because the sound irritates them. Most listeners do not have words to describe what is bothering them.

On the other hand, a song that sounds great, and continues to delight the listener even after many plays, is likely to add to the number of listens, which is important when listening via a streaming service. That could also increase sales of physical media, like vinyl and CDs. That results in more royalties for the artist and composer. And that ultimately will result in more time booked for your studio.

The irritation caused by poor recording has sometimes been called “listener fatigue.” It can come from many sources in the recording and playback equipment. It is important to note that a problem stemming from the mic preamp cannot be corrected after the track is recorded. It will always have that sound.

Can you hear the difference between a mic preamp that sounds great and one that does not? Sadly, there are people in our profession who cannot. That does not mean they are bad engineers or producers. It may mean that they just have never really learned how to listen. Their focus may be on other aspects of the song. That can be legitimate. They are focused on the musical elements of the song, not the details of the sound.

Or maybe they have become accustomed to the sound they are used to, and any other sound does not feel right to them. They prefer the sound they know. It helps to have an open mind about that, and also everything you do in the studio.

Does that make a difference to the ultimate listener? Maybe not. But I think it does matter.

You might conclude that a great mic preamp is only a benefit to those with “golden ears.” Well, I think all engineers should have golden ears. It’s part of our job. If we are working with a producer, I think it is the engineer’s responsibility to advise them if they hear something that is not right. And fix it, if that is possible.

We should all strive to be the best we can possibly be at doing our job. After all, it is an extremely competitive business we are in, and any advantage, no matter how small, should be worth pursuing.

A minor improvement in the sound, perhaps only a few percent, may not make a difference. But good engineers seek as many of those improvements as they can find. And after a while, a few percent here and a couple of percent there start to add up to a significant improvement in the sound.

This isn’t simply for our gratification. It’s not just to impress our peers. It also affects the artists we are recording. If the playback sound great to them, they will be inspired to play better. When their instrument or voice sounds better than they have ever heard it before, they are likely to mention it. That raises the enthusiasm level of everyone involved. That can result in a more inspired performance. The joy and enthusiasm of the players is felt by the listener.

I see that all the time.

That should be important to you. That’s why you pursued this profession, isn’t it?

Better recording encourages better performances, and the listener is likely to feel that enthusiasm. And that makes them feel good about the music.

Over my career, I have run into people who cannot hear the difference. I think they are lucky, in a way, because they will never have to strive to be better, and they will save a lot of money on equipment in the process. Superior equipment is more expensive.

In music-making, I think that the people who make music just for fun are some of the happiest musicians I know. They don’t practice much. They never try anything new. They simply enjoy playing or singing, perhaps with others with the same approach to playing. I think that’s great. Music should be fun.

And there are engineers with the same attitude toward recording. They just want to have a good time making mediocre recordings with their friends. That is perfectly acceptable in my book. There is too little joy in the world, so do what makes you happy.

Then there are others who are never satisfied. They want to learn everything they can about the art and science of recording. They strive to make every session better than the one before. Many of those people go on to have great careers.

Getting back to mic preamps, let’s look at some of the factors that affect the sound.

Not only must the mic preamp amplify the signal, but it must also provide the proper load on the microphone. All mics are designed to operate into a specified load impedance. That’s 1500 ohms for mics that conform to the standards.

A mic preamp that does not provide the proper load will change the sound of the mic. It might be subtle with some mics and preamps, or very obvious with others. That’s why standards have been established by the Audio Engineering Society. That makes microphone models perform consistently wherever they are used, and it provides the best possible sound from that mic every time.

Many mics do not conform to the standards. Most condenser mics that lack an output transformer have a lower than standard impedance. And some mics, like the SM57, are designed to work with a preamp with a 600-ohm input impedance, not the 1500 ohms in the standards. Many ribbon mics sound best with a higher than standard input impedance.

Does that mismatch make those mics sound bad? Not necessarily. But it does mean that many mics will sound slightly different, depending on the input impedance of the mic preamp.

All mic preamps have excellent frequency response. It should be flat from at least 20Hz to 20kHz, the range of normal human hearing. But better mic preamps extend that range, at both the low end and the high end. Does that matter?

I believe that it does. One factor is phase shift. Every electronic circuit is only flat over a range. If your mic preamp starts to roll off at, say 40Hz, it might be down several dB at 20Hz, and even more below that. And all roll-offs have some degree of phase shift. The intrinsic “equalization” of the low-end roll-off means that very low frequencies, perhaps from a kick drum, will have the fundamental note of the drum slightly out-of-phase with the overtones of the kick drum sound.

Does that matter? It might, because the kick may lose some of its punch. The drum loses its power. It starts to sound distant and wimpy. Boosting the lows will not fix it. Avoiding any phase shift of the overtones of any instrument makes it sound better.

The D.W. Fearn and Hazelrigg Industries mic preamps are flat down to 20Hz, and down only 3dB at 0.5Hz. That way, there is almost no low-end phase shift. And no loss of power in the kick drum sound.

The same applies to the high end. If the mic preamp frequency response rolls off rapidly above 20kHz, the sound of many instruments may not be as realistic as it could be. Again, it’s mostly the phase shift that causes the problem. It may be subtle, but it’s there. It’s easiest to hear in the articulation of the sounds. Instruments like piano lose some realism. Even voices suffer from a lack of believability because all those subtle sounds that we hear in the real world are not reproduced perfectly.

The D.W. Fearn and Hazelrigg Industries preamps start to roll off above 50kHz. That helps preserve the realism.

You might think that eq is the solution to these phase shift and roll-off problems, but it may only make a minor improvement, while introducing other problems into the sound. Most of the time, eq is not the answer. With an appropriate mic for the sound, and a good mic preamp, you should rarely need any eq at all. The exception might be on directional mics very close to the sound source, because of proximity effect that exaggerates the bass frequencies.

It is very rare that I use any eq on any mic, except for the bass roll-off needed on some mics.

As you probably know, I prefer the sound of vacuum tubes over solid state. That’s why all the D.W. Fearn products are 100% vacuum tube. There is a difference in the sound, and you can learn more about that in the episode, “Vacuum Tubes: Why They Sound Better for Audio,” from July 2020.

All professional mic preamps have very low noise. You should never hear any noise from the mic preamp in normal recording. If you are hearing noise from the preamp, the problem may be in the way your gear is set up. Listen to the episode, “Basic Electronics for Recording Engineers, Part 4, Gain Staging,” to learn more.

There are other factors that define the sound of a mic preamp. Most of them are circuit and component choices made by the designer. One big factor is the preamp input transformer. Manufacturers love to eliminate transformers because they are expensive, heavy, and take up space in the preamp. A good transformer should only alter the sound in a pleasing way, if at all. But then why do different transformers sound slightly different? There are lots of reasons, but a big one is the steel alloy used in the core of the transformer. That alloy, and how it is processed before being incorporated into the transformer, can have a subtle, but meaningful effect on the sound.

In theory, eliminating the input transformer should remove a source of potential sound deterioration. But sometimes transformerless inputs cause their own problems. That’s a topic for another time. Quality transformers are very transparent, and any modification to the sound tends to sound musical and pleasing to your ear. Also, od transformers are expensive.

Good equipment designers have lots of experience in real-world recording, and they can hear the things I have discussed. They design by ear, spending most of their product development time listening to their prototypes, refining them as they go along. It’s that few percent improvement here and a couple of percent there that make the difference.

I design my products using the same approach as I do when recording: I listen for the thing that annoys me the most. Then I find a solution that addresses that problem. Then I move on to the next thing that bothers me and fix that. When I have nothing left to fix, I am satisfied that I have the best sound I can achieve.

Of course, most recording sessions do not allow a lot of time to fine-tune the recording technique. Experience is the best way to avoid those problems during a busy session.

Audio equipment designers usually have a lot more time to identify and fix problems before the product is available to buy.

The more I record, and the more products I design, the quicker the process becomes.

If you are committed to your craft of recording, that should also apply to your sessions as well.

It is also helpful to realize that the standard equipment measurements do not tell the full story of how a mic preamp is going to sound. In fact, that applies to most studio equipment. I rarely look at the specifications of equipment I am considering for purchase. We make recordings for humans to listen to, not to please test equipment. I want to know what the device sounds like, not how it measures.

There are many aspects of the sound of audio gear that are difficult or impossible to measure. Perhaps some of those things could be measured, but there is not much incentive to do so. And for me, it doesn’t matter. I design equipment that sounds good to me, not necessarily what measures best with test equipment. You can learn more about that in the episode, “Microphone Preamplifiers: How I designed the D.W. Fearn preamps and how you can get the most out of them,” from August 2020.

Another amazing thing is that two mic preamps, or other gear, might have nearly identical measurements, but they sound very different. How do you explain that? It shows that your ear is a much better audio analyzer than even the most sophisticated test equipment.

None of us started out with the ability to hear and define those things that bother us. We had to learn how to do that.

The usual path for most engineers in the past was to work with an accomplished engineer at a major recording studio. Those motivated to learn would hear what their engineering mentor was doing and figure out how they did it. They learned how to get great sounds and make superior recordings. In the process, they learned how the engineer selected equipment, including microphones, to achieve the sound they wanted.

That option is not available to most budding engineers these days. If you do have the opportunity, make the most of it. Learn all you can. You will never get exactly the same sound as your mentor, but that’s OK. In fact, it is a good thing. We all have to develop our own sound, our own style. Most importantly, when working with an expert, you will learn how to listen, and that’s a vital skill that will help you every day of your recording career.

Even if you never have the opportunity to study with a master engineer, you can still achieve the level of professionalism you want. I know, because that’s how I learned. I had my own successful and busy studio for several years before I ever set foot in another studio. I knew what I wanted instruments and voices to sound like and I kept studying, listening, and experimenting so I could get closer to my goals. That process never stops for me, even decades later.

Learning on your own isn’t for everyone. But it is a valid approach for those who learn best that way. And no matter how you learn, eventually you have to stop being taught and simply teach yourself. Many of the great engineers I have talked with have mentioned this. Learn all you can from others, but the final polish on your technique must be done on your own.

Regardless of how you develop your recording skills, it is important to always keep experimenting and learning. Every session should be better than the last. For more on learning to listen, try the episode from August 2022, called, “Listening.” Links to all the episodes I have mentioned in this episode are in the description.

Today, I record mostly acoustic music, which is naturally pure and pristine. However, a lot of pop music is purposely distorted, either at the source, like an electric guitar with a lot of processing from pedals, or distortion is added later, in the form of “saturation.”

When recording that type of music, the mic preamp may not make much difference. You might purposely over-drive the preamp to get a particular sound. I think it is perfectly acceptable to do whatever is necessary to get the sound you want.

Some music is supposed to be annoying.

But if you are looking for beauty in your recording, then you need to take a different approach, and make sure you capture the sound as effectively as possible. And that means minimizing all the irritants that can creep into a recording if you are not careful.

I don’t mean some sort of audiophile recording technique. I mean getting the sound that best serves the music, doing whatever it takes.

Clean-sounding recordings keep the listener listening. It makes the artists perform better. And it makes your sessions far more relaxed and satisfying.

Mic preamps are a fundamental part of getting good sounds. Never underestimate the effect your preamps have on the final product.

Thanks for listening. I always appreciate your comments and suggestions. You can reach me at dwfearn@dwfearn.com

This is My Take on Music Recording. I’m Doug Fearn. See you next time.