I've seen there's a previous question that never got given a final answer. I'm trying to amplify a differential dynamic mic with the following specs through an SSM2019:
Type: Dynamic differential microphone
Frequency range: 70–9000 Hz +/- 6 dB
Sensitivity as lip mike: 4 mV/220 Ω
Impedance: 230 Ω
Noise suppression: 12 dB at 1 kHz
The mic only has Mic + and Mic- terminals, no ground pin. It's connected via a Nexus PT-120 TRRS jack, the tip and the first ring being for the mic and the second ring and sleeve for the headphones.
I only have 9V and 5V single ended supplies available for this application. From what I've seen here this unit is capable of operating on a single supply by giving the REFERENCE pin V+/2. I've connected up like this:
-REFERENCE: 2.5V (5V/2 through voltage divider)
-IN+: Microphone +
-IN-: Microphone -
RG1 -> RG2: 1k resistor (gain of about 9 if I'm not mistaken?)
All I get with this set up is really loud noise, but no hint of microphone input. As a new hobbyist, any reference diagram on how to wire this up would be greatly appreciated!
[edited by: carlosbeneto at 3:05 PM (GMT -5) on 27 Nov 2020]