Does anyone know of a DIY microphone pre-amp that runs at 9-12V and fits in a 1590B or 125B? I'd like something to fit on a very small acoustic/vocal pedalboard that will bring my SM58 up to line level before the signal hits my RC-3 looper. I've found some small mic pre's by googling, but they either don't have a PCB, are sized for racks and/or are powered at 18-48V. Any leads would be appreciated.
maybe overkill for what you need, but I use a Pigtronix Keymaster and I believe there is a DIY schematic floating around somewhere
Neil mcNasty has done vero layouts for various preamps here:
http://guitar-fx-layouts.42897.x6.nabble.com/Preamps-f24089.html
This mic preamp should fit the bill
http://www.parasitstudio.se/uploads/2/4/4/9/2449159/ina217_preamp.gif (http://www.parasitstudio.se/uploads/2/4/4/9/2449159/ina217_preamp.gif)
It works well with +/- 9volts aswell, so you can use a simple voltage inverter (7660, 1054 ect.) for the negative voltage. If you don't need the balanced outputs you can omit everything in the 5 bottom rows and take the output from C4 (cathode).
It's a variation of the "5$ mic preamp" and follows the INA217 datasheet with only a few minor changes