I am restoring a 35mm film projectors from the 1930s, which at some point had a Kelmar optical sound head added onto it. The solar cell outputs a balanced signal through an XLR jack that is very weak (around 60-70 mV). If I run the XLR straight into a mic input of a mixer I can get some recognizable audio if I crank the gain way up but it is extremely muddy. Here is a image of an oscilloscope reading of the output signal:
I would like to build a preamp circuit to get this signal up to line level. I am very new to electronics (more comfortable with the mechanical aspects of this project) and would like to design a circuit based around the SSM2019 IC. I tried to replicate a mic preamp schematic with poor results and ultimately I somehow fried the IC experimenting with it.
Before I order another one I want to see if I am on the right track at all.
- Is the SSM2019 an appropriate IC for this project?
- Do I need to correct for the DC bias of my input signal or is that insignificant?
- Can I/How can I design this circuit to run on DC power?
- How does the impedance of the solar cell affect my circuit design?
- If I measure across the outputs of the solar cell I read its 34k ohm resistance. Is that the same as the solar cell's output impedance?