Why use an external microphone preamp?

As a life long home-studio owner, I've built strong opinions about what the critical components are that create a good recording.

High quality recording equipment can quickly become an absolute black hole of financial investment. So what then is the most important invesment a home recording musician can make? Is is a nice microphone? A high quality external microphone preamp? Or will the biggest improvement in sound quality come from upgrading your analog to digital coverters/interface?

I encourage you to consider that a high quality mircophone preamp is the most important investment you can make in your studio. Plan on spending between $400-$1000 per channel.

A great mic preamp will make any mic sound great. This is true for a 57, a Chinese condenser mic or a $3,000 Neumann. Any mic will love going through a great preamp and benefit from it sonically. Most modern interfaces have high quality converters that will do a good job capturing the audio you are sending it.

However, modern digital interfaces have to skimp and compromise in many ways on the quality of the mic preamp in order to appeal to the largest customer base. When a unit provides many functions, it can appear useful, but generally speaking, its best to have dedicated equipment for each step of the recording process. This is true for many reasons including that different circuits, especially when one is analog and the other is digital, they don't like to share a power supply and ground. If a piece of equipment has a lot of features, that doesn't mean it sounds good. In fact, ofthem times the better the gear, the fewer the features. You'll find you don't need to work so hard to turn the signal into something pleasing. Great gear gives you a great sound without the need for a lot of eq'ing or compressing after the fact. And it takes eq and compression more musically.

An external microphone preamp will have its own dedicated high quality power supply. It's also important that it isn't sharing the interface's digital circuit power supply and ground.

So if you have a semi-decent microphone and a decent audio interface, I strongly suggest you consider making the investment in a nice microphone preamp. The most popular mic preamps fall into two categories: "clean" sounding and "colored" sounding. A clean preamp will work great for classical, jazz, and any kind of recording where you don't want to add saturation. A colorful preamp will add harmonic information aka "saturation" to the signal. This is what, in my opinion, makes your recording sound larger than life, and makes your speakers reproduce the music in a more realistic way. 

The colorful preamps are colorful becuase of their use of transformers. Transformers are big, heavy and expensive, but there truly is no better way for a signal to enter and exit a circuit. If the preamp uses a transformerless design and relies on opamps only, you will get a more clean and accurate reproduction of the signal.

Known makers of clean preamps are True Systems, Grace and others, while the common colorful preamps are Neve, API and the like.

Have questions? Contact me. Thanks for reading!

Graham