But as soon as I connect the required crystal (16Mhz) the circuit picks up noise (I assume from the crystal) and becomes unusable.
How do I decouple the powersupply so that the noise from the crystal is not amplified by the circuit (I already tried a decoupling capacitor of 100nF between V+ and Ground).

Problem solved, I used too small a decoupling capacitor! Works like a charm now (with 330uF)!

 

No it is not (see http://en.wikipedia.org/wiki/Heterodyne). The problem with heterodyne circuits is, as I said before, that they require tuning, which makes them unsuited for my application.

Well, I am certain that you could hear the rats making noise with the circuit from Alec, but the sound quality would not be good.

you're right, you did tell me that before. Sorry, my brain has been a busy mess these last couple of days.

I'll just step aside for now.

However, I would really like to hear an audio clip of what you record.

And also, I don't think a circuit that needs tuning would work for me either, it would basically hear one thing, but lose the rest.

 

ronv - can you share the electret mic LTS component?

Thanks.

ak

Sorry it took so long.

 

My LTS machine is down for ransomware removal, so I won't get to this for a while. But Thanks.

ak