Something for hardcore-solderers

[christian]

I built 4 stages, but its hell doing this stuff on perfboard

Schematic

Next project is the 32-stage phaser, on perfboard again!

ch.

[The Tone God]

Someone's using gEDA.

Does it have to use the 4013 ? They look like they are just being used as flip-flops. I think there are a few dedicated flip-flop ICs that might make the build easier.

Andrew

[markusw]

Sorry for the dumb question: how does the quantizer stage work??

regards,

Markus

[lovric]

  

there is an LFO. it is working the comparator's bias. comparators are doing something to the flipflops (flipping?). and it can be heard on the speakers

sorry for the dumber question: what does this do??

just visited your site, why this becomes better with more stages? can you compare it with any other octaver.

regards,
marin

[Peter Snowberg]

Excellent!!!

My hat is off to you. This circuit is truly unique. How does it sound?


TG: There are a few flip-flop chips out there but they tend to use common clocks from what I've seen.

[christian]

there is an LFO. it is working the comparator's bias. comparators are doing something to the flipflops (flipping?). and it can be heard on the speakers

sorry for the dumber question: what does this do??

just visited your site, why this becomes better with more stages? can you compare it with any other octaver.

Theres no LFO here! Its just an adjustable bias. I drew it wrong BTW, it should act as a voltage divider between 0v and virtual ground, gonna correct that in a minute.

Comparators are set up so that they have different tresholds, which rise in steps like 1v, 2v, 3v, etc..
If these are mixed in without the flipflops, you get quantized output. With 4 stages its like running the signal through 2-bit ADC and then thru 2-bit DAC. And adding more stages gives you more "bits", therefore better accuracy.

Then you just drive each "digitized" section thru octave-divider and mix them together.
To sound at least somewhat convincing youd need a LOTTA stages. 256 stages would give you 8-bit resolution

I think there are a few dedicated flip-flop ICs that might make the build easier.

As pointed by Peter, theres none that could be used here, since these all have their own clock inputs.

Well this sounds like a bad-ass octave-divider, but I did it only with 4 stages.
I see an opportunity to use something like ATMega32 uC here, has enough memory and inbuilt ADC to do this all digitally.
Just model D-flipflops into its RAM with 2 bits (store last-input & last-output) and use the value of the input as series of comparators.

Someone's using gEDA. Wink

I did represent an idea back then when I used to hang out here. I'd found this ADC circuit that had 1 comparator per bit,
and then sending each "real bit" to D-flipflops, but drawing a test wave an simulating the output, it didnt work as supposed.
Binary version of the wave is little different than just quantized.

ch.

[Processaurus]

Cool!  You got me thinking.  I read about a similar type comparator/flip flop circuit idea here a while ago, minus interesting bias circuitry.  One suggestion that seemed good for a possible incarnation of this was to use an LED driver chip instead of all the comparators, like the LM3915.  Now I'm thinking about how to intelligently reset the flip flops with the other comparators when the wave has decayed to where it is no longer clocking them.  Its hard for me to imagine how it sounds, with the flip flops being left in a random state.  Perhaps quite nasty?

[christian]

Its hard for me to imagine how it sounds, with the flip flops being left in a random state.  Perhaps quite nasty?

Well it is nasty, but so are the "standard" octave dividers with just 1 stage. This does a little burping in the end, but has a real nice tone-change as the note starts to decay, which happens when the resolution gets smaller.

I had these ideas few years back, also thought about the led-drivers and there might be something floating around that used led-driver as a wave-shaper which was a nice idea too. Takes away few chips, its just the flipflops, you only get 2 per chip

Note that I havent built this exact circuitry, mine was little different, so I'm not 100% sure about this, but the theory works and is proven.

ch.

[lovric]

christian,

thank you for the explanation. i stepped into this topic like it's a puddle and now i'm worried whether i could reach the bottom with toes 

the more bits it'll have the less the bad-ass sound? this made me look into  your site and i am really enjoying it.

marin