anyone ever built a crackle box?

[birt]

http://www.eam.se/kraakdoos/index.html

anyone ever built one of these?

[troubledtom]

who cares it's toooooooo cool, if you like noize. build it!!!
            - tom

[octafish]

Note the specific IC. Tried to build one with a standard opamp, won't work.

[Paul Perry (Frostwave)]

It's been built successfully by quite a few guys on the DIY-SYNTH list. It is correct that you need the exact chip specified, it operates by setting up ultrasonic and audio feedback using your fingers as variable resistors across the contacts. the compensation pin and various leakages are integral parts of the circuit, hence to make a classic cracklebox, you need the chip, whihc may be available from surplus or recoverable (was a common chip in its day).
www.eam.se/kraakdoos
www.crackle.org/CrackleBox.htm

[darryl]

Our there specific call letters for this chip at the begining like UA709, LM709, doing a search and do not see anything.

Darryl

[troubledtom]

THERE ARE MANY 709'S TO BE HAD WHICH ONE IS THE ONE?
            - TOM

[Tim Escobedo]

So, has anyone here actually built one of these? I was underwhelmed by the samples. Similar results can be had using a common CMOS Schmitt trigger chip. I even got similar results from a "personal security alarm" gadget from the local $.99 Store by replacing the resistor in the RC timing circuit with two brass screws.

Seems not worth the trouble of hunting down a 709 chip. Unless it can make sounds dramatically different from those posted on the web site.

[Coriolis]

Hi Tim, may I ask how you would do that with a schmitt-trigger? And what chip?
See, I tried building a cracklebox a while ago (used an LM709, I think) and that didn't work.
I would like to get that sound tho...

C

[troubledtom]

bump

[Coriolis]

second the bump...