Experimentalists Anonymous - Analog Bitcrusher

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
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grrrunge
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Post by grrrunge »

Here you go! Vero is verified and all ;)
Sounds awesome...

I used 1N4148's and a 2N5457 instead of 1N914's and a J201. For some reason, using a 2N5457 seemed to let more sound through than a J201.
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controller700
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Post by controller700 »

:shock:
very interesting project!
I have to give this a try...
So which IC types did you use?

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Post by Nocentelli »

+1 Awesome stuff, going to build this ASAP: I love vero, and I love simple one-knob builds. Been meaning to build that catalinbread heliotrope, but it's a good deal more complex than this. What pot did you use (I've got a 1MC that I'll try out - might try adding a 1M resistor in series as a "range" option switch) and what's the value of the electro across the power rails? I'm guessing 100uF, but it's not on the schem.

Thanks again.
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grrrunge
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Post by grrrunge »

controller700 wrote::shock:
very interesting project!
I have to give this a try...
So which IC types did you use?
I used a NE5532 for the buffers (the upper IC) and a TL072 for the oscillator (the lower IC) :)
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Post by grrrunge »

Nocentelli wrote:+1 Awesome stuff, going to build this ASAP: I love vero, and I love simple one-knob builds. Been meaning to build that catalinbread heliotrope, but it's a good deal more complex than this.
I'm on the heliotrope as well, but i stumbled upon this circuit, and realized i had most of the parts laying around, so i decided to give it a go.
Nocentelli wrote:What pot did you use (I've got a 1MC that I'll try out - might try adding a 1M resistor in series as a "range" option switch)
It seems to me that a regular logarithmic pot works better.
I didn't have any 3n3 caps, so i subbed a 6n8 in its place, and i'm guessing it's got something to do with the oscillator frequency, cause i actually ended up using a 250K log pot, which takes it all the way from slightly downsampled mellow timbre through to chaotic low frequency rumble
Nocentelli wrote:and what's the value of the electro across the power rails? I'm guessing 100uF, but it's not on the schem.
Yes, it's a 100uF ;) sorry about that.
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Post by bigrigg »

Anyone build this besides the OP? I just have a clean sound. No clock oscillator deal. I used the same diodes and IC as OP on vero. Also on breadboard. It's like the transistor isn't getting the pulse at the gate. Any help would be appreciated. Voltage value checks or audio probe checks? Should I have audio on both sides of C2? Thank you

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Post by grrrunge »

bigrigg wrote:Anyone build this besides the OP? I just have a clean sound. No clock oscillator deal. I used the same diodes and IC as OP on vero. Also on breadboard. It's like the transistor isn't getting the pulse at the gate. Any help would be appreciated. Voltage value checks or audio probe checks? Should I have audio on both sides of C2? Thank you
Start by posting photos of your board, front and back, so we can troubleshoot ;)
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Post by ~arph »

I think this thing could benefit from a simple envelope detector to shut down the oscillator when there is no signal at the input. Just as the heliotrope btw.. bit noisy
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Post by grrrunge »

~arph wrote:I think this thing could benefit from a simple envelope detector to shut down the oscillator when there is no signal at the input. Just as the heliotrope btw.. bit noisy
Yes. At higher sample rates, the LFO bleeds through at the sampling frequency, when there's no signal going through.
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Post by earthtonesaudio »

~arph wrote:I think this thing could benefit from a simple envelope detector to shut down the oscillator when there is no signal at the input. Just as the heliotrope btw.. bit noisy
Word. If you were clever you could get it to kill the oscillator in such a way as to leave the FET open (otherwise it would effectively kill the audio as well).

Projects like this generally also benefit from a couple other things:
1. use a low-current opamp for the oscillator
2. isolate the oscillator opamp's supply rails from the audio supply rails (RC or pi-decoupling)
3. separate bias dividers for audio and oscillator (in this particular case it looks like this is not a big deal)
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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Post by ~arph »

earthtonesaudio wrote:
~arph wrote:I think this thing could benefit from a simple envelope detector to shut down the oscillator when there is no signal at the input. Just as the heliotrope btw.. bit noisy
Word. If you were clever you could get it to kill the oscillator in such a way as to leave the FET open (otherwise it would effectively kill the audio as well).

Projects like this generally also benefit from a couple other things:
1. use a low-current opamp for the oscillator
2. isolate the oscillator opamp's supply rails from the audio supply rails (RC or pi-decoupling)
3. separate bias dividers for audio and oscillator (in this particular case it looks like this is not a big deal)
Sentence.
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Post by grrrunge »

~arph wrote:
earthtonesaudio wrote:
~arph wrote:I think this thing could benefit from a simple envelope detector to shut down the oscillator when there is no signal at the input. Just as the heliotrope btw.. bit noisy
Word. If you were clever you could get it to kill the oscillator in such a way as to leave the FET open (otherwise it would effectively kill the audio as well).

Projects like this generally also benefit from a couple other things:
1. use a low-current opamp for the oscillator
2. isolate the oscillator opamp's supply rails from the audio supply rails (RC or pi-decoupling)
3. separate bias dividers for audio and oscillator (in this particular case it looks like this is not a big deal)
Sentence.
:applause: Brilliant! :D
Earthtones, thanks for that. I was thinking along the lines of adding a noise gate after the output, but this sounds like a much better solution :)
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Post by earthtonesaudio »

~arph wrote:Sentence.
Haha, took me a full minute to get this. :block:
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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Post by ~arph »

Yeah I have a bizarre sense of humor...

Btw, I did an envelope controlled aliaser once with a PLL and a nurse quacky envelope circuit, and a simple comparator for the noise gate. It stopped the oscillator when there was hardly any signal and kept the gate open..sounded a bit funky though:



:mrgreen:

Obviously needs a better envelope circuit...
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Post by bigrigg »

grrrunge wrote:
bigrigg wrote:Anyone build this besides the OP? I just have a clean sound. No clock oscillator deal. I used the same diodes and IC as OP on vero. Also on breadboard. It's like the transistor isn't getting the pulse at the gate. Any help would be appreciated. Voltage value checks or audio probe checks? Should I have audio on both sides of C2? Thank you
Start by posting photos of your board, front and back, so we can troubleshoot ;)
thanks, built this off of Ivlark's vero design and it worked. (other than the slight freq whine noise everyone mentions)

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Post by bangerang101 »

Hey, I just wanted to add... you can ground the carrier frequency through an un-used lug on the bypass switch to eliminate the carrier frequency when the pedal is bypassed. Like say take a wire after the 1m resistor (the one that is connecting the jfet and oscillator together), and connect it to the switch in a way where it will short this wire when the effect is bypassed. There may be a "pop" when the pedal is engaged though, but imo is better than a constant carrier frequency... and is a simple, easy fix that can be done to an existing pcb.

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