Help with Kelmar sound cell

[Julian Baquero]

Dear members, I bought a Kelmar sound cell for my very sick Mayafot May Minor 35mm projector, see attached photos. The seller did not give any information about the cell. I would like to know if someone here can help me with the following questions:

1. Is this a STEREO or a MONO cell, it has 3 wires (red, green, black)?
2. Can you share some information about how the cell must be connected to a analog preamp? I don't have a sound processor.
3. Do I need coupling resistors in the connection?
4. Can I use the cell with a 650nm 5mw line laser instead of a exciter lamp?

Thanks for any advice given, BR Julian

[Nantawat Kittiwarakul]

It's not 8mm...but I'll reply anyway.

1. That 3 wires would probably be stereo cell with black wire as common.
2. In a pinch, you can connect that to whatever that does have MIC input. It should give you some sort of audio then.
3. Yes. Forgot the proper value. You might have to experiment this using a variable resistor.
4. Haven't tried with laser light source before. But I once tried new red led with standard (old) mono cell. Works brilliantly to my ears. Since most solar cell does have relatively wide range of spectrum sensitivity. That means it will "see" anything from infrared to UV - shouldn't be a problem for red laser too.

[Julian Baquero]

Nantawat, thank you very much for your help. Regards!