If you're looking to diversify your arsenal of microphones and have some extra cash handy, a tube microphone might be just what you need to add a flavorful alternative to some of your more neutral-sounding microphones.
What Is a Tube Microphone?
A tube mic is a type of condenser microphone, in that it uses internal amplification ("head amp") to raise the level of the signal coming from the capsule. And like any condenser mic, a tube mic also needs a preamp to boost the signal to line level for recording. However, unlike condenser microphones that employ "solid-state" circuitry, tube mics instead use a vacuum tube as part of the microphone's circuit. How do these two distinct condenser mic technologies differ in terms of sound?
How Does a Tube Microphone Sound?
While all types of condenser microphones excel in terms of their high-sensitivity, wide frequency response and precision, tube mics and solid-state condenser mics differ in their sonic personalities. Tubes are famous for their warm, colored, vintage-like vibe, while solid-state amplification is often more neutral. That's not to say that solid-state condenser mics must sound boring; they can also vary in sonic characteristics, from bright and airy, to rich and deep. But tube mics generally have a more identifiable character, smooth and somewhat "rounded" with a full lower midrange.
There are exceptions to this rule, of course, but for the most part, these rich harmonics and mellowed transients are why some vocalists and musicians opt to record with tube mics. They may not be as honest as solid-state condenser mics, but because of the ways in which they naturally distort and compress sound, they generally have a more "musical" and fluid quality.
How Does a Tube Microphone Work?
While there's little need to delve into all the internal parts of a tube microphone to understand how to use it, it is important to note that tube mics have more complicated power requirements than that of a typical condenser mic. They can also break quite easily if not set up properly.
When you buy your tube mic, you'll find that it comes with its own power supply unit, which has two connectors in addition to the power supply's AC cable. The microphone usually connects to the power unit via a 7-pin (sometimes 6-pin) cable, while a 3-pin XLR cable runs from the output of the power supply to the mic preamp. It's important to reiterate that you'll still need a good preamp. The power supply that comes with the microphone package is simply to deliver a higher voltage and current needed to power the tube.
A tube amp is a delicate flower–if you don't set it up or break it down properly you run the risk of breaking it. You have to warm it up before you use it for optimal performance and cool it down before you put it away so the tube doesn't get damaged. You should also ensure that you plug in all the parts in right order. So, if you decide to buy a tube mic, it's a good idea to look up the correct procedure for setting it up safely.
Types of Tube Mics
Large Diaphragm Tube Mics
If you're looking for the most versatile tube mic, one that can capture rich and majestic vocals and singular instruments alike, a large diaphragm microphone is the way to go. Unfortunately, tube mics tend to be more expensive than solid-state condenser microphones.
Still, there are decent budget-friendly options that can deliver professional results like the RODE NTK 1" Condenser Microphone. It's a great entry-level option for those looking to record a transparent, yet warm sound. It works for everything from vocals to acoustic guitars and uses high-quality Jensen Transformers to deliver quiet output at high-gain levels. It's at least half the price of more industry-standard options, yet the final result is approximately on par with the best tube mics out there.
If you're willing to throw down a little extra cash, the Warm Audio WA-47 is designed to deliver the vintage personality of the legendary U47 microphones at a fraction of the price. This model allows you to choose between nine polar patterns, making it useful for a number of applications. Whether you're looking for a close-up vocal or grand ensemble recording, the WA-47 will help you cover all your bases.
Now for something that's as aesthetically magnetic as it is talented, the Soyuz SU-017 is somewhat of a boutique model that's handmade in small batches in Russia. It offers the most classic characteristics of a tube mic, conveying a warm, retro tone while retaining fantastic articulation throughout the frequency range. The only downside to this mic (as well as some of the pricier models) is that although you can change up the polar patterns, you will have to manually swap out the capsules, which are all sold separately. But if all you need is a cardioid design, then the SU-017 should work beautifully out of the box.
Small Diaphragm Tube Microphones
Small diaphragm tube microphones are particularly useful for acoustic instruments like guitars and pianos and are also often bought in matched pairs for stereo recording. They tend to have a better transient response and are often more natural sounding than large diaphragm condenser mics. They're also easier to place at an optimal position for sound capture of an instrument. And since small diaphragm mics can handle high sound pressure levels, some models also work well for percussion and drums.
The Telefunken ELA M 260 is a classic example of a small-diaphragm tube condenser mic that's geared for acoustic instruments and vocals. This model is also sold in pairs for stereo recording.
Active Ribbon Tube Microphones
Ribbon microphones are known for their notably honest recording of instruments. A ribbon mic employs a figure-8 polar pattern, which means it picks up sound from both ends while sound from the sides of the mic (off-axis sounds) are effectively blocked out. This makes them useful when recording in a room with multiple instruments. And given their tolerance for high sound pressure levels, they are great for capturing loud instruments like trumpets and drums. When you combine their precision and transparency with the warmth produced by tube design, you get an incredibly nuanced, yet rich presentation of your instrument. The famous Royer Labs R-122V is a prime example of what this union can offer. For a more in depth exploration into ribbon mics, check out our article, What is Ribbon Microphone? – Link to this article once live.
At the end of the day, although tube mics tend to be quite pricey, if you're looking for that warm, silky, vintage flavor, no other type of microphone can produce it as faithfully as a well-designed tube microphone.
For more information about the new tube mics listed above, including additional features, specs, and highlights, be sure to check out their detailed product pages. Or drop us a line below, and we'll do our best to answer all your comments and questions.
