# Question about a sample and hold **URL:** \ **Category:** Uncategorized\ **Created:** [April 11, 2023, 4:57am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080 "2023-04-11T04:57:24Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Jewceman1](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@Jewceman1](https://lookmumnocomputer.discourse.group/u/Jewceman1)\ **Post date:** [April 11, 2023, 4:57am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/1 "2023-04-11T04:57:24Z")
Hey I was wondering about something I once heard with what I believe were sample and hold modules. I remember in a electronic music tech class, my professor mentioned that computers can’t exactly give a truly “random” result or output since it is all based on algorithims while “random” from a universal sense is completely different. And if memory serves me right, they mentioned that sample and hold modules are the closest thing that can give that sort of “random” output. I’m not sure if this is true or how true it is, or if I misremembered the lecture, but was wondering if anyone knows or has heard about this and maybe can give a source or lead me into the right direction of this claim? ---
**Author:** ![Bpbby](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bpbby/32/15259_2.png) [@Bpbby](https://lookmumnocomputer.discourse.group/u/Bpbby)\ **Post date:** [April 11, 2023, 6:16am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/2 "2023-04-11T06:16:44Z")
To me, a sample and hold will give you a “random” output if you feed it with a random input. So the randomness is not generating by it, it changes the frequency (sampling) of it. But then there might different sample and hold version that I have not seen yet. ---
**Author:** ![jaradical](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jaradical/32/12069_2.png) [@jaradical](https://lookmumnocomputer.discourse.group/u/jaradical)\ **Post date:** [April 11, 2023, 6:33am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/3 "2023-04-11T06:33:29Z")
> [@Jewceman1](#): > > computers can’t exaclt give a truly “random” result our output since it is all based on algorithims Pretty accurate, although now a days you can get processors with a true analog random source in them, something like a reverse biased diode you’d find in an analog noise generator. They can be used as is, or to seed one of the psuedo random algorithms that the prof was probably talking about. Cheers ---
**Author:** ![Jewceman1](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@Jewceman1](https://lookmumnocomputer.discourse.group/u/Jewceman1)\ **Post date:** [April 11, 2023, 7:03am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/4 "2023-04-11T07:03:34Z")
That’s really interesting, are there any modules that give an almost “true random” output or get somewhat close to it? Are all sample and hold modules able to do this even if they’re a simple diy build, or would it have to be specific ones that can do it? ---
**Author:** ![jaradical](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jaradical/32/12069_2.png) [@jaradical](https://lookmumnocomputer.discourse.group/u/jaradical)\ **Post date:** [April 11, 2023, 8:15am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/5 "2023-04-11T08:15:50Z")
@EddyBergman has one with a write up [here.](https://www.eddybergman.com/2020/05/synthesizer-build-part-31-noise-module.html) His write up says it’s based off of Ray Wilson’s [Noise Coruncopia](http://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=NOISECORNREV01/NOISECORNREV01.php&CATPARTNO=NOISEBRD001&PN=1&SONGID=NONE) ---
**Author:** ![K.ostas](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@K.ostas](https://lookmumnocomputer.discourse.group/u/K.ostas)\ **Post date:** [April 11, 2023, 10:13am UTC](https://lookmumnocomputer.discourse.group/t/question-about-a-sample-and-hold/6080/6 "2023-04-11T10:13:30Z")
A good and cheap source of randomness is the noise that is caused by the emitter-base junction avalanching of silicon transistors. Finding a good noisy transistor, however, requires a little bit of trial and error (typically destroying a few transistors in the process). Zener diodes with a low Zener voltage are a good alternative for producing random noise.