[sdiy] SMT transistor for white noise?

[Loscha]

Electric Druid has code and circuits for noise generators on 8 pin
microcontrollers, which I'm sure are adaptable into other platforms.

https://electricdruid.net/white-noise-source-mm5837-mm5437-replacement/
https://electricdruid.net/noise2-white-pink-noise-source/

On Sun, 14 Dec 2025 at 12:02, Jay Schwichtenberg via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Looking at the EDN schematic again I think there is an error. Think C1
> should go from Q1's emitter and ground, not emitter and +12. I built
> mine with C1 going to ground.
>
> Jay S.
>
> On 12/13/2025 1:05 PM, Mike Beauchamp wrote:
> > On 2025-12-13 09:35, Brother Theo via Synth-diy wrote:
> >> I switched to the 2 transistor noise circuit and have had zero issues
> >> since. The Future Retro 777 re-release uses that circuit.
> >
> > Hi Timothy, doing some duckduckgo-ing, I found a few...
> >
> > https://www.edn.com/simple-white-noise-generator/
> >
> >
> https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_5
> > (figure 20)
> >
> >
> > The EDN article is interesting. Seems like the second transistor is
> > just the amplification stage and the increased noise level is because
> > of the addition of C1. I don't understand the function of C1.. time to
> > get out the breadboard.
> >
> > Mike
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