[sdiy] Kraakdoos

[Pete]

I have been working on a Kraakdoos myself, and I also plan on building
it into a Pac-Tec case! I currently have it on the breadboard, and I
added a 10k pot at the + voltage side to control the volume. This
thing is really loud and the pot really helps. I also tried to put the
pot on the output going to the speaker and that also worked on
controlling the volume. Though im not sure where it would be best to
put the pot permanently later on? My prob with the Kraakdoos is that
it is not stable at all, and I know the thing is not stable already
but I mean that there is allot of noise and it picks up radio signals,
and thats really anoying. I was thinking that it needs power
decoupling. What do you guys think? I built mine according to the
schematic on this site,

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

Sometimes mine sounds like the mp3 samples on that site but the noise
and radio interference really ruin the sound. I think that im getting
feedback or unwanted oscillations, im not sure im still learning. Does
yours sound like this? Also I would add the transformer right where
you place the speaker and connect a 1/4" jack to that and see if that
works, im not sure im guessing. Maybe even add a switch so you can go
from the built in speaker to the jack. I would like to be able to plug
some headphones into the thing so you could play with it while on the
buss or Bart (SF subway). It is fun to play with, but I really want to
get it to sound good first before I build it into the case.

 On another note I went to see the Moog documentary in SF recently.
Before the film they where showing these homemade films from the 60's
and there was this guy playing a Kraakdoos in the film! It was pretty
big and he was playing it by putting his fingers right on the metal
cans of the transistors! It also sounded very good and stable. It had
all kinds of knobs on it. I wish I could find the details on that one.

pete



On 5/9/05, Metrophage <c0r3dump23 at yahoo.com> wrote:
> Needed something to get me soldering again, so I decided to finally
> make of of these noisy things. It's in a Pac-Tec handheld case with
> seven brass knobs clustered on top. The audio output is a 4-ohm speaker
> from a broken CasioTone. At first I was not terribly enthused about the
> sound, but it has been engaging me more. Got to feel where the chaos
> attractors are!
> 
> As it is, the only problem is that it is way, way too loud. Like "can't
> play it indoors" type loud. This won't do, as I was hoping it could be
> a toy for my 14 month old boy. I'm guessing a 100k mod-pot might do it,
> attenuating the signal after the transistors. We'll see shortly.
> 
> Something which puzzles me is how to make an output jack connection to
> interface with other gear. On a Dutch page, I deciphered that an 8 ohm
> to 10k ohm transformer can be used. This is cool, because I have two,
> but I don't know which way to connect it, or where in the circuit to
> put it. I also worry about whether I should take other precautions for
> DC. Any possible advice on outputs? This thing is a fun toy, but the
> signal can sound a bit brutal at times. Need to protect those ears and
> gears.
> 
> CJ
> 
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-- 
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