[sdiy] single 9 volt battery white noise source

[Oren Leavitt]

Dave Leith wrote:
> This circuit looks good...except the IC's are powered by dual 9Volt
> batteries. Looking for a single 9V battery as I'm wanting to add a
> noise source to a thingamakit http://bleeplabs.com/thingamakit/
> 
> On 7/17/09, David G. Dixon <dixon at interchange.ubc.ca> wrote:
> 
>>>Reading thru the documentation for the Rainmaker seems that this would
>>
>> > be the best solution. Is the following really the case?
>> >
>> > quote" Common designs use invariably Zener diodes or reverse-biased
>> > transistors base-emitter junctions as white noise generators. The main
>> > snag of these circuits is that a supply of at least 12V is required,
>> > therefore a big battery pack or (more commonly) mains supply is used
>> > as power source."
>>
>>
>>Ray Wilson's Sound Lab uses the reverse-biased E-B junction method, on a 9V
>> supply, and it works just fine (presuming you choose a transistor which
>> actually makes noise!).
>>

For single-ended 9 volt operation, you might consider a digital CMOS 
pseudo-ramndom noise generator.
Most any of the 15 volt CMOS noise gen designs out there should work 
fine at 9 volts.
This will work much more reliably on a single 9 volt source than the 
semiconductor junction type white noise sources.

- Oren