[sdiy] reverse biased NPN vs Zener diode for noise...

[nicolas]

I haven't done any comparative testing, but the advantage of the zener diode is that you can order one off the shelf and it will have a known voltage drop and fairly predictable noise character.  On the other hand using a transistor you will have to experiment a bit, maybe adjust things to suit the voltage drop you find or test several transistors to find one in the right range.  My understanding is that if you do manage find a suitable transistor it will give you a bit more noise at a somewhat lower voltage drop than a zener.  With zeners, use the highest voltage you can accomodate because below 10V they aren't so noisy.

Cheers,
Nicolas

--- On Fri, 30/10/09, Benjamin Budts <mailing at gigaspeeds.be> wrote:

> From: Benjamin Budts <mailing at gigaspeeds.be>
> Subject: [sdiy] reverse biased NPN vs Zener diode for noise...
> To: "synth-diy DIY" <synth-diy at dropmix.xs4all.nl>
> Received: Friday, 30 October, 2009, 3:13 AM
> 
> Hi,
> 
> I'm looking into building a noise module and I'm wondering
> what the audible difference is between
> reverse biased NPN based  vs Zener diode based... :-D
> 
> Just wondering if there's somebody on the list who tested
> this...
> 
> Thx
> Benjamin
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> Synth-diy at dropmix.xs4all.nl
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> 


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