[sdiy] WTB/WTT: 709 op amps

[dj hohum]

On 6/27/07, John Mahoney <jmahoney at gate.net> wrote:
> At 05:59 PM 6/27/2007, dj hohum wrote:
>
> >So what's a cracklebox, I suppose I could google for it but what's the
> >fun in that.
>
> It's an odd, hand-held, electronic noisemaker:
>          http://www.crackle.org/CrackleBox.htm
> The real ones look pretty cool, and I've seen some nice DIY versions.

Ok, well, it didn't take much googling. I think that's the strength of
the unit, it can look cool.

> >More to the point, why is it dependent on the 709?
>
> I have no idea. I don't know that anybody knows.
>
> The circuit is simple, maybe you should make one with your 709.
> Schemo and MP3s are here:
>          http://noisybox.net/electronics/cracklebox/


Yeah, thanks for the link. I suppose the best reason I can think of is
why waste a perfectly good 709. ;) Looking at the 709 datasheet six of
the seven pads are inputs to some part of the circuit and five of the
seven pads are outputs from some part of the circuit. At the very
least you need an op amp with similar external compensation inputs to
get the variety of feedback loops that you can obtain with the 709.

The CA3030 also has a number of similar inputs/outputs, however, the
device is somewhat simpler than the 709.

While I can appreciate the minimalist nature of such devices, and in
this case the history, I have never been a fan of  touch feedback
noisemakers. For my tastes, it moves in the wrong direction. Perhaps
one could choose four to six of the most interesting feedback loops
and make them voltage controllable. That might yield an interesting
noise module, then again, it might not.