[sdiy] Popcorn Noise Generator?

[Michael Ruberto]

The best popcorn noise I've heard was when I took an old transistor preamp 
and reduced it's supply voltage with a potentiometer. At a certain level the 
pops only happened on the downbeat. Reducing the voltage more made the pops 
start to trigger off every drum sound, and eventually all peaks in the music 
which did in fact start to sound like pure noise.

Also, take your telephone next to a gas stove and set one burner to ignite. 
For more popcorn turn on more burners.

M. A. Ruberto

>From: "drheqx" <drheqx at heqx.com>
>To: "'Ray Wilson'" <raywilson at comcast.net>,        "'harrybissell'" 
><harrybissell at prodigy.net>,        "'Glen'" <mclilith at charter.net>
>CC: <synth-diy at dropmix.xs4all.nl>
>Subject: RE: [sdiy] Popcorn Noise Generator?
>Date: Sat, 9 Jul 2005 09:45:35 -0400
>
>Ray,
>Is it limited to Op Amps? I was under the impression that all silicon
>junctions would produce this type of noise when biased on.
>
>heqx
>
> >For people who are wondering what popcorn noise is...
>
> >Quote from "INTUITIVE IC OP AMPS FROM BASICS TO USEFUL APPLICATIONS"
>(not
> >shouting the title really is all caps)
> >Author: Thomas M.Frederiksen
> >National Semiconductor Technology Series
> >Copyright 1984 Thomas M.Frederiksen
>
> >START QUOTE
> >"Popcorn" Noise. A peculiar additional ac noise mechanism is sometimes
>seen
> >when an oscilloscope is used to observe the output ac noise voltage of
>an >op
> >amp. Digital signalling from outer space seeme to be taking place.
>Pulses
> >can exist with widths of many milliseconds where the constant baseline
>of
> >random ac noise abruptly steps up by a large enough factor (say, 5:1)
>to
> >trace out a rectangular pulse, with the baseline ac noise now occuring
> >across the top of this pulse, as shown in figure 3-30. This abrupt type
>of
> >noise is called popcorn noise because of the sound it makes coming from
>a
> >loudspeaker. Popcorn noise is caused by a defect that is dependent on
>the >IC
> >manufacturing technique.
>
> >This ac noise results from abrubpt changes in the input current between
>the
> >normal level and a second, qusistable level that differs by
>approximately
> >100 pA. Evidence of popcorn noise is closely monitored by the
>manufacturer.
> >however to guarantee that it is not present requires special, time
> >consuming
> >(and therefore expensive) testing.
> >END QUOTE
>
>Testing and manufacturing techniques, I'm certain, have come a long way
>in
>21 years so I'd bet this is not as prevalent as it used to be.
>
>Cheers
>
>Ray
>
>
>
>
>
>----- Original Message -----
>From: "Ray Wilson" <raywilson at comcast.net>
>To: "harrybissell" <harrybissell at prodigy.net>; "Glen"
><mclilith at charter.net>
>Cc: <synth-diy at dropmix.xs4all.nl>
>Sent: Saturday, July 09, 2005 6:27 AM
>Subject: Re: [sdiy] Popcorn Noise Generator?
>
>
> > The grainy noise generator is white noise through a window comparator.
>The
> > window is adjustable so you get a few clicks or a lot of clicks.
> >
> > Ray
> >
> > ----- Original Message -----
> > From: "Glen" <mclilith at charter.net>
> > To: "harrybissell" <harrybissell at prodigy.net>
> > Cc: <synth-diy at dropmix.xs4all.nl>
> > Sent: Friday, July 08, 2005 8:40 PM
> > Subject: Re: [sdiy] Popcorn Noise Generator?
> >
> >
> >> At 10:14 PM 7/8/2005, harrybissell wrote:
> >>
> >>>how about start with white noise, then rub it into an active diode
> >>>section biased so that only peaks above a DC level would be passed.
> >>>
> >>>Those peaks would still be analog (of varying amplitude) but would
>become
> >>>less frequent as the DC level was increased.
> >>>
> >>>alternately you could get an old Gershon Kingsley record and have
>some
> >>>REAL popcorn noise...
> >>>
> >>>H^) harry
> >>
> >> What about feeding white noise through a narrow window comparator?
>That
> >> would make all the spikes the same amplitude, but is that really what
>we
> >> would want, if trying to generate popcorn noise?
> >>
> >> What about a weak radioactive source, and a Geiger Mueller tube?
> >>
> >> What about sampling the voltage drop across a blinky neon lamp?
> >>
> >> I'm just wondering. I have to admit that I'm not totally sure what
> >> isolated popcorn noise sounds like. I've heard a few audio amps which
>
> >> popped and cracked due to a circuit failure, but I don't know if
>that's
> >> really popcorn noise.
> >>
> >> Does anyone have a reference wav sample of the stuff?
> >>
> >> thanks,
> >> Glen
> >
>
>
>
>
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