Echo circuit for Dynamic Microphones

This may help

The issue is there's not enough output from the dynamic mic. Best way is to have an external preamp...but, maybe you could get enough gain with a few value changes...It's hard to say exactly, because the data sheet is pretty sketchy...Here's a quick way to get 26 dB more gain...that should help SNR...if it works, maybe we can push the technique a bit farther...

We've changed a few caps and resistor values. R4 and R5 represent the revery path. Main change is the two caps, and R1, which probably was 10K-15K previously. You may want to bump up C1 a bit to move the low end roll-off down, but I wouldn't bother to start.

See enclosed file...LT1001 is just a placeholder for components on pins 15 and 16.


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