Want to build a simple microphone mixer

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I'm new to diyAudio, so I'm not even sure I'm posting in the right forum. I've come up with an op amp-based design for a 4 or 6 input microphone mixer, and I'm looking for any tips on the design. I'm attaching a schematic.

The mic input stages are differential amps with 40 dB gain, and these are combined in a summing stage with unity gain per channel. For the microphone level output, I'm planning to use a Jensen transformer, the same one that's used in DI boxes.

I didn't use any caps in the design. Should there be a blocking cap before the summing stage, or maybe before the transformer?

Is the overall gain appropriate for a mixer with mic-level output? Any ideas will be appreciated.


Thanks!
 

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  • MicrophoneMixerSchematic.pdf
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Hi,

Your mixer or this :
Behringer Xenyx 502 Mixer at Gear4Music.com
What would you choose ?

preview.jpg



or this :

preview.jpg


or this for 4 balanced mic inputs :

preview.jpg


rgds, sreten.

Yuor a lot better off buying and then modding if quality really matters.
 
Last edited:
Thanks. I am simply working on something for a drummer to hear
guitars and vocals. Loud and close to the touch for adjusting while
playing. Sound quality is just not that important lol.

Hi,

You will need to give a lot more salient and accurate information
before anyone can work out the best approach to your problem.

Foldback is not a new problem and there are lots of approaches.

rgds, sreten.
 
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