# Bitcrusher/bitswapper/sample rate reducer module

**URL:** <https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751>\
**Category:** DIY STUFF\
**Created:** [July 8, 2021, 9:50am UTC](https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751 "2021-07-08T09:50:44Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\
**Post date:** [July 8, 2021, 9:50am UTC](https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751/1 "2021-07-08T09:50:44Z")

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Maybe something interesting here 🙂

[![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/3/4/34f738a323c4326d350218055bfe185a771a0471.jpeg "Bitcrusher, bitswapper, sample rate reducer - Modular in a Week 13.7") ](https://www.youtube.com/watch?v=YyoNgZ59NXg)

[![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/c/c34448f8680b7bb4e2e04da0373e34a5fef9c96f.jpeg "Panel and Schematics for the Bitcrusher/bitswapper/sample rate reducer") ](https://www.youtube.com/watch?v=apKdotggD04)

 ![bitcrusher rate reducer](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/b/ba01caab0ca432eef43b858c49352eda762615d7.jpeg)

For best quality, here’s the link to original schem pdf

> **[Schematic\_BIT%20crusher\_2021-07-06.pdf](https://www.dropbox.com/s/ujza3f5h7d61ndg/Schematic_BIT%20crusher_2021-07-06.pdf?dl=0)**

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**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\
**Post date:** [July 8, 2021, 11:33am UTC](https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751/2 "2021-07-08T11:33:51Z")

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Schematic reminds me of a certain [Jedi](https://lookmumnocomputer.discourse.group/t/the-funny-pages/1552/178). The ADC0809 is rated for absolute maximum voltage -0.3 V to Vcc+0.3 V on its input and output pins. There’s nothing here to protect them.

In particular, presumably the audio in here is supposed to be in the 0–5 V range, not ±5 V, not only to stay within spec but to make it actually work over the full waveform.

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**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\
**Post date:** [July 9, 2021, 8:26am UTC](https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751/3 "2021-07-09T08:26:32Z")

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I knew by posting the schem that there would be some security modifications / improvements proposed, but it seemed to be a good basis.

I also saw that @Jos had posted a comment on the vid 😉

> To bias the input signal you need not use an opamp. If you lift the input signal of the ADC using 2 resistors (one connected to gnd and the ADC-input, the other to the positive input voltage and the ADC-input) and feed the signal to their center via a capacitor you should be set

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**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\
**Post date:** [August 26, 2021, 7:34am UTC](https://lookmumnocomputer.discourse.group/t/bitcrusher-bitswapper-sample-rate-reducer-module/3751/4 "2021-08-26T07:34:32Z")

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Juanito More make recentely also a Bit Crucher module (no schematic for the moment)

[![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/3/5/35394836f9dfebc1d38c3f18bac2a0afc5506693.jpeg "Hardware-only DIY bitcrushing!") ](https://www.youtube.com/watch?v=lKfBwo-1pJw)

Description :

> Audio comes in to the circuit through an attenuating potentiometer and then an amplifier that will clip/saturate the signal at 5 volts peak-to-peak.
> 
> The next stage centers the audio signal around 2.5V, to take full advantage of the next stage, which is a ADC0820, which turns the audio level into an eight-bit number. The ADC0820 has an “interrupt” function that lets you send it a clock and basically lower the sample rate of the audio.
> 
> The bits then go to a pair of CD4066 quad bilateral switch ICs, which get their gates turned on or off with a comparator ladder that turns off each bitstream, starting with the least significant bit, up to the next-to-most significant bit (the MSB can always get through).
> 
> Then the bits get processed by another comparator ladder, with resistors between the outputs and the less-significant-bits down the ladder, so the values of the more-significant-bits get duplicated down the line – bitcrushers that leave their “crushed” bits at high-impedance state lose loudness as the bits get crushed, this one doesn’t (it gets LOUDER). Finally, the byte gets turned back into audio with a DAC0808 chip…