Kraakdoos...it doesn't work arggg

[benfox]

Hi,
I've try to built the Kraakdoos...it doesn't work arggg
I only have humming sounds or white noises...I use a 709 but it's the 14 pins version is it a problem ? I've check the pinout from the datasheet
pin 1 = pin 3 (in the 14pin version)
pin 8 = pin12 ( in the 14pin version)

I notice that there is differences beetween this shematic :
http://www.logosfoundation.org/kursus/2005.html
and this one
http://www.eam.se/kraakdoos/
I follow the last one because it seems more clear to me.
I use bc558 and bc548 instead of 557 and 547 (is it a problem ?)

Any idea on what's going wrong

[benfox]

is it the right place to post it ?

[jksuperstar]

THis is the right place. LEt me dig up those parts & see what I find. I'll back to you tomorrow!

[bugbrand]

Hiya Ben

I've used 14pin 709s just fine.

I'Ve sometimes had wierd noise problems - especially seemed to happen when I tried using larger touch plates.

I found these 2 mods helped a lot (especially if you try to add the audio output as detailed on my electronics page)::::

1 - add a 10n cap from pin 2 to ground.

2 - add a 1M resistor from the touchplate end of cap C1 (the cap that comes off of pin 1 of the 709)

[benfox]

Thanx a lot guys...
During my experimentations i lost a bc558...hell
What could i put to replace this one (pnp...i guesss)
I use crocodile claw (you understand). It's with a wire soldered to the board at one end and atthe other there is a claw crocodile style 2centimeters long...
Is it a problem
Your cracke box ouput is made for a speaker output i guess but i want to plug it into an amplifier...or a mixing board...with the original output it should work isn't it ?

[bugbrand]

Yo Ben,

Nah, the standard circuit doesn't work for plugging into an external amp/mixer --- I'd love someone to explain why it doesn't work! My extra circuit works fine to get the sound into the mixer/external amp

For the transistors I've used BC547/BC557s and 2N3904/2N3906 - both work fine and, actually, I've also used a combination of BC547/2N3906 and that worked fine too.. General NPN and PNP configs should work fine I think.

[benfox]

Ok thanx i've add a tiny audio transformer on the output and it works i don't have all the sound i expected even on a speaker.
When you said putting a 1Mega resistor from the pin 1 to ground...i've try it cuts every thing ?!

[bugbrand]

Nah, the 1Meg resistor should connect to ground after the cap that connects to pin1 (ie by the touchplate)

[benfox]

sorry for that stupid question forget this one....
Ok i did right now the 1meg is at the right place but i loose a lot of ionteresting sounds with this...so i will not put it...

[benfox]

It dies yesterday....
Am i too much electric for the stuff ?