Finding a great USB Mic Preamp for under $300

A mic preamp is used to boost the signal level of your microphone so that you can record your voice. Some people think you can just plug your dynamic or condenser pro microphone directly into your computer sound card and start recording. Unfortunately, because of technical issues like impedance matching, that's not the case. You need to run the mic through a microphone amplifier first. Fortunately, there are some really good and affordable preamps on the market.

There are two major directions you can go with a microphone preamp. On the one hand, you could choose a non-USB mic preamp or audio mixer, and then feed the preamp or mixer output into your sound card.

On the other hand, you can choose microphone amplifiers with a USB output so you can hook up directly to your computer and completely avoid your soundcard. This direct hookup to USB may be especially valuable if you don't have a good sound card (meaning either the PCI sound card that came with your computer, or no sound card at all). This wiring connection is a simple, direct hookup for digital audio as diagrammed below.

On this page, I'll examine three extremely good USB mic preamps that are available for less than $300 US. They each feature a USB output, as well as analog (non-USB) outputs, and phantom power for condenser microphones.

Edirol UA 5 USB Mic Preamp

The Edirol UA 5 mic preamp packs a lot of flexibility into a small package. I liked that the UA 5 has XLR inputs for pro microphones, as well as 1/4" jacks for not-so-pro microphones or other line-level equipment like an electric guitar. The UA 5 also has 48 volts of phantom power, which is important if you have a condenser mic that requires it. There are RCA input jacks so you can hook up equipment like cassette decks or CD players for amplification, and even coaxial and optical inputs if you're feeding through a DAT player or other digital-output device.

What is very attractive about the Edirol mic preamp is the wide variety of output plugs on the unit.

First, there's a USB output so you can hook directly to your computer (Mac or PC).

Second, there's a set of RCA jacks on the outputs so you could plug to your computer sound card, a minidisc recorder, a cassette deck or a recording CD unit. There's also a set of 1/4" jacks for outputs that, with adapters, could feed any of those same pieces of equipment.

Third, there is a set of digital outputs in both optical and SPDIF formats. This would be useful if you're feeding into a digital audio tape machine (DAT) or have an optical or SPDIF digital input on your sound card.

The specifications on the Edirol UA5 mic preamp are also good. Edirol has a strong reputation for building high-quality, low-noise equipment that is also affordable to the home recording enthusiast. The fact that the power supply is off the unit and packaged in a "wall wart" is a bonus to keeping external noise to a minimum.

I personally didn't like that the microphone XLR plugs are on the front of the unit, but I only consider that a minor inconvenience. I also personally don't need the coaxial or optical input and output capability because I don't have such inputs on my sound card, but for people who do, this is a real plus for the UA 5.

Overall, the Edirol UA5 is an extremely flexible, high-quality microphone amplifier that I highly recommend for use with your mic.

System Requirements: Windows 98/Me/2000/XP, Mac, OSx

Price: $375 (Only $289 at Soundprofessionals.com)

M Audio Duo Mic Preamp

The M Audio Duo mic preamp by M Audio (also known as Midiman) is great for recording mics and line signals over USB in extremely high quality. Although it doesn't have the flexibility of the Edirol UA 5, I found it to be a strong performer at a great price.

The M Audio Duo mic preamp has the standard XLR inputs for mics, plus phantom power for your condenser microphones. It also has 1/4" jacks for line/mic inputs. I particularly liked that the M Audio Duo has "pads" on the inputs and outputs. A "pad" is a feature that lets you attenuate a very loud signal by a preset amount, or boost a weak signal by a preset amount. In this case, the boost is +4 dB, and the attenuation is -10 dB. I also found it particularly attractive that all of the input jacks are on the back of the unit, leaving the front clean of wires.

The outputs are in three formats: USB for your computer, S/PDIF (digital out) and 1/4" jacks. With appropriate adapter cables (like 1/4" to RCA, or 1/4" to 1/8" stereo), the 1/4" outputs can drive the inputs on a minidisc recorder, tape deck or other recording unit.

The dynamic range of the M Audio Duo is particularly impressive (107 dB mic to line) and distortion is extremely low (less than 0.002%). As with the Edirol UA 5, the power supply is contained in a "wall wart" off the actual mic preamp, so noise is kept to a minimum. The specifications in all respects are quite good.

Overall, the M Audio Duo mic preamp is a solid performer. It's not as flexible with inputs and outputs as was the Edirol UA 5, but it satisfies all of my four criteria (USB out, non-USB out, XLR in with phantom power, and a line in for occasional use).

System Requirements: Windows 98/Me/2000/XP, Mac, OSx

Price: $349 (Only $259 at Soundprofessionals.com)

M Audio Mobilepre Mic Preamp

The Mobilepre mic preamp by M Audio (also known as Midiman), is a great addition to any home recording studio. Best of all, it doesn't require any power supply! The Mobilepre gets it's power from the USB port ... a feature that has it's pluses and minuses as I'll discuss below.

The Mobilepre has the requisite XLR connectors and phantom power provisions for professional condenser microphones. Of course, if you have a dynamic microphone, you don't need to turn on the phantom power of the preamp. There are also 1/4" line level input jacks for a guitar or even a tape deck. I was looking for the ability to occasionally hook up a tape deck for pre amplification, so this was good. However, I didn't like that the jack for one channel is on the front of the unit, and the jack for the other channel is on the back. For my particular case of hooking up a stereo cassette decks for playback, this would be inconvenient, but you may not need such flexibility.

As for outputs, the MobilePre has three types of outputs. First, there's a USB output for hooking to your computer. Second, there's a set of 1/4" jacks for outputs that could feed other equipment or a sound card, assuming you have the requisite adapters or cables. Third, there's a 1/8" stereo jack for output (like a mini-headphone jack). Again, with the appropriate cable, you could use this to drive the input of a tape deck, minidisc recorder, or other recording device.

As stated before, the MobilePre microphone amplifier is powered by the USB port of your computer. This is great because you don't need to find an open plug on an extension cable to make it work. On the other hand, I wanted the ability to leave my computer off because of fan noise, so I wouldn't be able to use the MobilePre in that instance.

The dynamic range of the MobilePre is good at (91 dB mic to line) and distortion is 0.01%, making it a little less "clean" than the UA5 or Duo, but still a good unit for recording your voice for information products, CD's, poetry readings, training cassettes, and any other vocal application.

Overall, the M Audio MobilePre mic preamp is a fine unit for anyone who needs to provide pre amplification to a professional microphone. If you need to amplify a piece of equipment like a tape deck or CD player, wiring up the inputs would be a bit cumbersome, so I would suggest using this unit only for microphones (or single input devices like a guitar).

The fact that you don't need an external power supply is a big bonus. Just remember that it derives power from the USB port, so you'll need your computer powered on in order to use it (especially for phantom power). This would be fine if you've got a quiet computer, or even if you're doing field recording with a laptop computer.

Read detailed information about the MobilePre

System Requirements: Windows 98/Me/2000/XP, Mac, OSx

Price: $179 (Only $149 at Soundprofessionals.com)

Summary of Microphone Amplifiers

These three mic preamps offer extremely affordable ways to boost the signal of your dynamic or condenser microphone for input into your computer. They each offer low noise, so they make your microphone sound great.

The Edirol UA 5 and M Audio Duo offer a slightly cleaner sound quality than the MobilePre, but the MobilePre offers the benefit of not requiring AC power in order to operate.

The Edirol UA 5 offers the most flexiblity of inputs and outputs, while the MobilePre is the least flexible.

The M Audio Duo is my favorite of the bunch because I don't need the optical inputs and outputs of the Edirol UA 5, the mic plugs are on the back, and it has analog outputs so I can use it with my minidisc recorder, too. Figure out your specific needs and make a choice. Any of these three preamps will serve you well and each costs less than $300!

Visit The Sound Professionals to look for a microphone, microphone accessories, and Microphone Amplifiers (a mic preamp)

David Caban, the Web Audio Advisor, helps people integrate audio into their website in order to gain more sales and make a stronger connection with visitors. Learn more about web audio and read his product reviews at www.WebAudioAdvisor.com