[sdiy]

[Fernando de Izuzquiza]

I also find Ray's circuit cool, I will build more than one.
I was also thinking on VC the graininess/gate+trig.
I found a very simple circuit based on two 1N4742 zener and is voltage
controllable. I built it but didn't work very well; almost for shure it's my
fault (or that the diodes are too recently manuf.?). The author was quite
unresponsive though.
Take a look (there are other designs and formal theories from Peter
Blasser):  http://www.blasser.com/smchaos/
"voltage controlled zener cracklesh"

Fernando
--



f
*




> De: Oren Leavitt <oleavitt at ix.netcom.com>
> Responder a: Oren Leavitt <oleavitt at ix.netcom.com>
> Fecha: Thu, 16 Oct 2003 10:50:50 -0700 (GMT-07:00)
> Para: Ray Wilson <rayw at csd.net>, Synth-Diy <synth-diy at dropmix.xs4all.nl>
> Asunto: Re: [sdiy] Diodes won't make noise
>
> Hi Ray & List,
>
> I've found that my milage varies with zener diodes as a noise source.
> Same thing with me, I have this one 1N4742 that will wake up the dead!
Stick
> this one in any of our existing circuit designs, and they will clip! Other
> zeners are rather quiet.
> Transistor BE junctions seem to give me more consistent results. I've
found
> 2N5087s (PNP) to be really noisy - at least among the batch that I have.
>
> I've seen your multi-noise source - it's nice!
> A cool idea for the 'grainy' output, would be to make the span of the
window
> comparator voltage controllable, making the 'grainyness' VC'able.
>
> One thing I've found helpful for juction noise sources is to place the CW
and
> CCW ends of a pot across the V+ and V-, connect the wiper to a 47K
resistor,
> connect the other end of the 47K to the noise zener, the other end of the
> zener is connected to ground.  AC couple the 47K/zener to the rest of the
> circuit.
> This way, using the pot, I am able to dial into the 'sweet' spot of the
noise
> source and find the best 'whiteness'.
>
> HTH,
> Oren
>
> -----Original Message-----
> From: Ray Wilson <rayw at csd.net>
> Sent: Oct 16, 2003 4:53 AM
> To: Synth-Diy <synth-diy at dropmix.xs4all.nl>
> Subject: [sdiy] Diodes won't make noise
>
> Hi All
>
> In some recent experimenting with my multi-noise source I came to the
> conclusion that zener diodes are NOT a consistent source of noise sources
> (that sentence sounds a little wierd). At some time in the past I have
used
> the specified diode and it made more noise than I ever saw before but that
> seems to be the rare exception. Anyway I have updated my multi-noise
source
> module to use a selected 2N2712 or a selected 2N3904 in case anyone is
> thinking of building it.
>
> I also finally made boards from the artwork and they do work fine. I
tweaked
> a couple of resistor values too.
>
> It is here:
> http://atlas.csd.net/~rjwsoft/multinoisemodule_exp.html
>
> Cheers
>
> Ray
>
>
>
>
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