Microphone Preamplifier

[HeaD]

Hi all!

I have bought a new firewire audio interface for my recordings. It's a modest Behringer F-control FCA202. Unfortunately it have no input for a microphone. It only have two UNBALANCED ¼" inputs.



I would like to connect the microphone to an input, and I'm looking for a simple 9V powered microphone preamp project. Do you have any ideas? Thanks!

[Branimir]

this is not 9V powered mic preamp, but never the less, results of this device are excellent! (beats the crap out of any behringer mic preamp hey, it's an improved amek preamp!)

http://www.akustische-kunst.org/audio/micpre2500.html

[Aharon]

I would buy a small mixer from Behringer and/or a tube mic pre from ART.
To build a half decent pre from scratch would cost you at least  $50.

[HeaD]

Thanks Branimir and Aharon.

Another question: what would happen if I use an MXR Micro Amp instead of a microphone preamp?

[Dave_B]

There are a couple of chips that can handle this cheaply.  The 9v thing makes it a little tougher though.  The INA217 will run down to +/-4.5v, but that's the minimum.  Circuits based on that or the the SSM2019 can be built reasonably.  You'll likely spend more on the XLR jack and case.

There's also the Green Pre.  It's more complicated, but it has a lot of fans and there's plenty of documentation (including a layout). 

You might have a look at the Group DIY forum.  That's the kind of gear they're building.

[Mark Hammer]

Thanks Branimir and Aharon.

Another question: what would happen if I use an MXR Micro Amp instead of a microphone preamp?

The Micro Amp is intended to provided enough gain to bring a guitar level up to what a guitar amp preamp input can stand.  It isn't awful, but it may not provide sufficient boost to allow your firewire device to treat voice mics right (there is a substantial gap between voice mic levels and guitar pickups),  Then again, it IS possible that the Behringer unit is designed to need very little assistance to voice mic levels to make the unit behave optimally.

[Aharon]

I've built the Green Pre....great preamp but like I said,the cost is more than you would pay for the ART tube pre.
Aharon