[sdiy] Uniformly distributed noise generator?

Ian Fritz ijfritz at comcast.net
Mon Jun 10 22:48:26 CEST 2013


At 01:35 PM 6/10/2013, David G Dixon wrote:
> > indeed, I thought of using a digital source myself, but was
> > hoping the analogue gods here could come up with something
> > fully analogue. I'm certain there's something out there..
>
>I've given up on analog noise sources, personally.  It is so much easier to
>get nice noise with a digital source.  The biggest problem with analog noise
>is the extreme amplification required, which picks up every tiny little
>problem in your circuit/system.  Plus, it just doesn't sound that good to
>me.

The problem with digital sources, it seems to me, is that you can't feed 
them into a S/H to get random voltages.  Careful board layout and 
decoupling are easily applied to make nice clean analog noise 
sources.  Mine sounds pretty good to me, but I did have to sort through a 
few dozen devices to get one with acceptably low 1/f noise.  The biggest 
mistake people make is to assume that the noisiest devices (greatest 
voltage output) make the best noise sources.  This is abolutely untrue; 
those always have a large 1/f component.  My best device actually had about 
the lowest output of the batch I tested.

Ian 



More information about the Synth-diy mailing list