Dual Mic-Pre :-

Be warned. The SSM 2017 is getting very hard to get so perhaps you should check on it's availability before you get too far into this project.

INA217 and THAT1510 are suggested equivalents. I have not be able to get either of these chips so this project is proving to be a problem. I live in hope.

The beginning of the recording chain seems like a logical place to start and since I think that making a Microphone is doable it might be better to leave that to others with more resources. So a Microphone Preamplifier is the next best thing.

The pretext for this project is to end up with quality Dual Mic-Pre that can be used in the studio or in the field with say a Camcorder. It is intended for Battery powering which keeps you very mobile and negates the need for mains wiring and so is a safe first project. However if you want permanent rack mounted unit then add a mains power supply and a rack box, no problem.

The simplicity of this project is down to SSM2017 microphone preamplifier chip. It has self adjusting Common Mode Rejection and so it couldn't be easier to set as there is no setup. It also has the very reliable LM833 op-amp as a buffer and unbalance drive and an SSM2142 balanced line drive output chip. Again the SSM2142 is very reliable and easy to use. For information on these ICs refer to the data pages.

Levels and Distortion

The circuit diagram .......

PCB board check plot and overlay should help to identify all the parts and where they fit in the scheme of things.

Pictures help to put things into their correct perspective

More about batteries

Click the thumbnails to view 480x360 pixel versions of the JPGs.