Help me troubleshoot my first stripboard layout

[Groverradagast]

Hey Guys,

Please be gentle, this is not only my first post on EM, but it's also my first attempt at a stripboard layout. I ran across Eric Archer's "sound cameras" http://ericarcher.net/devices/sound-cameras/ and had to build one. I then found this circuit diagram:



I built it on a breadboard and it worked wonderfully. The only change I made was to replace R1 with a fixed resistor. Then I drew this up in Illustrator and built it. My goal was to make it as compact as possible, as it's mounted in a small box. I could have made it easier to read by making it larger, but didn't...Forgive me if it's messy, as this is my first layout. To make it simpler to read, any wires/jumpers that connect to ground are green. Also I didn't bother labeling the components, since I already knew they worked when I tested it. The yellow blob is the ceramic capacitor (47nF). Just assume that the correct resistors are in the right places, and remember R1 is now just a resistor.



When I turn it on I get a strange descending self-oscillation that sounds like letting the air out of a balloon...I have quadruple checked for bad connections, solder bridges, and errors and can't find any between my layout and my actual board. So my conclusion is that I have made some kind of error in translating the circuit diagram into a layout. I've looked it over many times now but I need some fresh eyes.

So here's my question: Would someone be willing to check my layout for errors?

And here's the reward: If I get it working I'll go record some interesting things and post the resulting audio.

Thanks in advance,
Rob

[PHOBoS]

[Groverradagast]

Thanks for the reply PHOBoS!

It might be a few days before I get the chance to try it, but I really like the idea of attaching an audio source to the second half of the circuit! That would at least rule out that portion of the circuit as the culprit.

I'll update if I learn anything or (fingers crossed) get it working.

Cheers