/diy/ - Do It Yourself

>>1845816
Did you measure voltage when you connect mic between pins 2 and 1? Your mic could draw more current than your designed power supply, and cause voltage on mic to drop below 9 V. If mic is drawing 5 mA, there will be 7.65 V drop across R3, R4 and R5, which when you have 12 V on the input gives the mic only 4.35 V. I would start with something simpler like pic related, your schematic includes low pass filters to make power supply more clean, but you should first start with a basic circuit without any filtering and add some if there is a noise problem.