What is a microphone preamplifier? It’s an essential piece of gear that boosts the mic output signal — but the ideal goal is that it’s “a straight wire with gain.” It serves one purpose only: to take the tiny voltage that comes out of a mic and boost it up to a higher voltage. That’s it. Simple, eh? Well, not so fast.
When designers sit down to create a mic preamp, there are several decisions and options they have to determine. Here’s a list of just a few of those design options that will impact the sound.
- Transformer/Transformerless
- Direct coupled
- Solid-state/Tube
- Discrete components/Integrated circuits
- Class A/Class AB
- Bandwidth — ultra-wide or limited
- Input impedance — switchable or variable
- Input pad
- Stepped gain/Continuously variable gain
- Output attenuator/range
- Power-supply voltage
- Output impedance — switchable or fixed
And then there are functional differences that will influence its usefulness but have less influence on the sound, such as whether to include:
- Phantom power
- Polarity reverse switch
- Dedicated ribbon-mic input or setting
- Output type (XLR, USB, ADAT)
- Hi-Z input (for DI) and input impedance
- Highpass filter and at what frequency
- Metering (VU meter, multi-segment LED, single LED)
- Overload indication (to indicate clipping/near clipping)
- Equalization
- Number of channels
- Form factor (desktop, rack [1U, 2U], half-rack, in-line)
- Size (large, standalone desktop box or as small as an XLR connector)
- Price
As you can tell, it’s far more complex than the proverbial “straight wire with gain.” Do any of those choices have an impact on the sound? You bet they do.
How Many Preamp Options Are There?
A search on Sweetwater.com for the term “microphone preamp” returns 234 results. Does that surprise you? It certainly did us. We’ve heard lots of preamps but certainly not all 234. That doesn’t even count the mic preamps in consoles and interfaces!
We decided to grab 21 of our favorite mic preamps and compare them on female and male vocals to see what differences (if any) we could perceive. We recorded the results so you can listen and see what differences you hear. Can you tell an expensive tube preamp from a less expensive solid-state preamp? Listen and see.
The Preamps You’ll Hear
Here’s the list of the 21 preamps we decided to audition. They cover a wide range of prices and options. As you can see, we chose to include only standalone preamps — no interfaces or consoles.
- Rupert Neve Designs Dual Shelford microphone preamplifier
- API 3122V 2-channel mic preamp
- Rupert Neve Designs 5211 2-channel microphone preamp
- Millennia HV-3C 2-channel microphone preamp
- Chandler Limited TG2 Abbey Road Special Edition 2-channel microphone preamp
- BAE 1073MP microphone preamp with power supply
- Neve 1073DPA 2-channel microphone preamp
- Great River ME-1NV desktop microphone preamp
- Warm Audio WA73 microphone preamp
- API Select T12 2-channel tube microphone preamp
- Chandler Limited REDD.47 tube microphone preamp
- Hazelrigg Industries VLC vacuum tube microphone preamplifier/direct injection/equalizer
- Manley Core reference tube channel strip
- Universal Audio SOLO/610 tube desktop microphone preamp
- Acme Audio MTP-66 tube desktop microphone preamp
- Maag Audio PREQ2 dual mic/line/DI preamp with EQ
- Solid State Logic XLogic Alpha Channel microphone preamp & EQ
- Focusrite ISA One desktop microphone preamp
- Grace Design m101 half-rack microphone preamp
- Daking Mic Pre One desktop microphone preamp
- Cranborne Audio Camden EC1 microphone preamp & headphone mixer
Take a Listen
For this listening session in Sweetwater Studio A, engineer Shawn Dealey, assisted by Jason Peets, asked female vocalist Kamryn Richard and male vocalist Sahaj Ticotin to sing on original songs. He set up a Telefunken U47 for the male vocalist and a Telefunken ELA M 251E for the female vocalist. We patched into each preamp individually (with the same cables) and did one take through each.
Kamryn Richard
Kamryn is currently working at Sweetwater, helping with artist relations. We’re delighted to have her (and her talents) making a stop on her way to her own artist career.
Sahaj Ticotin
Sahaj is the lead singer for the alternative metal band Ra and a frequent studio client at Sweetwater Studios. We’re thankful that he took the time to sing for us on this project.
What to Listen For
Take a listen to each vocal recording: all the technical details, including distortion, noise, headroom, etc. Then listen for the consonance, presence, warmth, body — the musical details. Last, try to turn off your analytical mind and just listen to the voice and respond to whether it’s communicating with you, whether the technology is enhancing the performance. Does the sound make you smile?
Female Vocal
Male Vocal
What Did You Learn?
There are so many different preamps that it can be overwhelming to decide which is right for you. That’s why we have so many knowledgeable Sweetwater Sales Engineers standing by to help you find the right vocal preamp — one that fits your needs, application, and budget. Give us a call at (800) 222-4700.