Animal Factory Amplification

New Hosted Sub-Forum. Check it out here:
Not exactly a new manufacturer but new to us. Check out their pedal and eurorack product and extend them a welcome all the way to Mumbai!

Dual CD4046 Cracklebox

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: Kent, Joe., luketeaford, Kent, Joe., luketeaford

User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Dual CD4046 Cracklebox

Post by Repeater »

Image

Image

My tribute to the Cracklebox by Michel Waisvisz and Geert Hamelberg.

Obviously this one's a little different because it uses a pair of PLL chips instead of an opamp, but in spite of different circuitry there are some commonalities:

(1) It abuses cheap and readily available ICs via the simplest and perhaps stupidest means possible: directly poking IC pins. (2) The LM709 has external frequency compensation pins and the CD4046 has its own sort of bandwidth limiting via resistors (or fingers in this case) at pins 11 and 12. (3) Like the original Cracklebox, this circuit is pretty much silent unless prodded. (4) It makes squeals and fart noises that are unique to each player.

There are only FOUR (4) components needed for the barebones version and it costs about one US dollar to make. With some additional circuitry, it can be the heart of a chaotic gesture-controlled synthesizer system. I hope that you enjoy it.

https://soundcloud.com/martin-freem/dua ... cracklebox
Last edited by Repeater on Mon May 01, 2017 9:49 pm, edited 5 times in total.
basicbasic
Super Deluxe Wiggler
Posts: 1098
Joined: Wed Aug 06, 2014 6:35 pm
Location: Sydney, Australia

Post by basicbasic »

That's awesome. Seems easy to put into a Euro panel too. I love simple circuits like these! :sb:
ClausF
Veteran Wiggler
Posts: 525
Joined: Mon Oct 08, 2012 12:01 pm
Location: Germany, FFM

Post by ClausF »

Great, as always :yay: :yay: :yay:
User avatar
Moos Gummi
Common Wiggler
Posts: 87
Joined: Mon Apr 11, 2016 11:02 am
Location: Germany

Post by Moos Gummi »

Is there a reason this couldn´t be a single, feeding back to itself? Maybe with a little filter?
User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Post by Repeater »

Moos Gummi wrote:Is there a reason this couldn´t be a single, feeding back to itself? Maybe with a little filter?
Yes.

The additional $.50 in parts buys you stereo operation and opportunities for cross-modulation.
User avatar
NS4W
Super Deluxe Wiggler
Posts: 1299
Joined: Thu Jan 12, 2012 11:42 am

Post by NS4W »

I'll be adding this to a newbie soldering workshop - should be fun! Thanks for sharing :party:
User avatar
mskala
Super Deluxe Wiggler
Posts: 2750
Joined: Thu Mar 27, 2014 7:33 am
Location: Toronto
Contact:

Re: Dual CD4046 Cracklebox

Post by mskala »

Repeater wrote:(1) It abuses cheap and readily available ICs via the simplest and perhaps stupidest means possible: directly poking IC pins.
Is this going to be a static-discharge problem?
North Coast Synthesis Ltd.
Twitch stream (Mondays, 3pm Eastern)

If you tell me that your goal is systemic change toward radical acceptance, and I see that you treat those you perceive as lesser-than with the same kind of scorn and derision that pushed me toward this insular little subculture where I feel comfortable [. . .] then you’ve successfully convinced me that your acceptance is not radical and the change you want not systemic. - "When Nerds Collide"
User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Re: Dual CD4046 Cracklebox

Post by Repeater »

mskala wrote:
Repeater wrote:(1) It abuses cheap and readily available ICs via the simplest and perhaps stupidest means possible: directly poking IC pins.
Is this going to be a static-discharge problem?
I've never had problems with modern CMOS and static discharge and I've working with similar circuits for a few years. YMMV of course.
User avatar
glennfin
Ultra Wiggler
Posts: 873
Joined: Sun Apr 19, 2015 1:19 pm
Location: Winston Salem, NC
Contact:

Re: Dual CD4046 Cracklebox

Post by glennfin »

I'd use sockets for those IC's. There's a good chance that repeatedly touching unprotected floating pins/connections on a Cmos device will damage the device. :ripbanana:
mskala wrote:
Repeater wrote:(1) It abuses cheap and readily available ICs via the simplest and perhaps stupidest means possible: directly poking IC pins.
Is this going to be a static-discharge problem?
User avatar
alka
Common Wiggler
Posts: 215
Joined: Wed Mar 31, 2010 7:08 am
Location: neverwhere
Contact:

Post by alka »

Thank you for sharing! :party:
New album out now on Vince Clarke's VeryRecords
https://alka.fanlink.to/auguries
User avatar
FetidEye
demonic space drone
Posts: 2241
Joined: Mon Dec 06, 2010 5:00 pm
Location: Red Zone
Contact:

Post by FetidEye »

yes, thanks! Lunetta stuff is cool!
User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Post by Repeater »

glennfin wrote:There's a good chance that repeatedly touching unprotected floating pins/connections on a Cmos device will damage the device. :ripbanana:
Generally that's the conventional wisdom, but this is a special case...

The only "floating" input in this circuit is the Signal Input (pin 14)... but it's not a digital logic gate! There's a linear amplifier inside that tries to amplify whatever you plug into it up to logic levels to drive the phase comparators. Generally, most people would want to amplify signals externally instead of using this feature of the CD4046. Don Lancaster writes about this in the CMOS Cookbook: "Linear operation causes extra amplitude-variation sensitivity, jitter, tearing and generally poor noise immunity." I believe that this irregularity is the source of much of the interesting behavior in this circuit.

Anyway, you don't need a pull-down or pull-up resistor there. :tu:
User avatar
emmaker
Super Deluxe Wiggler
Posts: 1039
Joined: Sat Mar 10, 2012 5:07 pm
Location: PDX

Post by emmaker »

CMOS does not like static and can blow up really easy when zapped.

I'd put a low value resistor (50-100 ohms) in series with the touch pads along with protection diodes to the power rails used by the chips.
User avatar
mskala
Super Deluxe Wiggler
Posts: 2750
Joined: Thu Mar 27, 2014 7:33 am
Location: Toronto
Contact:

Post by mskala »

emmaker wrote:CMOS does not like static and can blow up really easy when zapped.

I'd put a low value resistor (50-100 ohms) in series with the touch pads along with protection diodes to the power rails used by the chips.
If, as Repeater says, these chips are able to withstand static anyway, then it doesn't matter. But if static were a serious issue, then a series resistor that size would be no protection at all. Static charges are in the range of a few thousand volts. A 100 Ohm resistor would pass a few tens of amperes for as long as the charge lasted, and that's far more than the chip can withstand. In order to be useful for static protection, a series resistor would have to be in the hundreds of kOhm, bringing the maximum current down to what the chip's internal diodes can support. Maybe a little less if you're adding diodes of your own, and you trust them to switch faster and have less voltage drop than the chip's own.
North Coast Synthesis Ltd.
Twitch stream (Mondays, 3pm Eastern)

If you tell me that your goal is systemic change toward radical acceptance, and I see that you treat those you perceive as lesser-than with the same kind of scorn and derision that pushed me toward this insular little subculture where I feel comfortable [. . .] then you’ve successfully convinced me that your acceptance is not radical and the change you want not systemic. - "When Nerds Collide"
User avatar
emmaker
Super Deluxe Wiggler
Posts: 1039
Joined: Sat Mar 10, 2012 5:07 pm
Location: PDX

Post by emmaker »

along with protection diodes to the power rails used by the chips
If, as Repeater says, these chips are able to withstand static anyway, then it doesn't matter. But if static were a serious issue, then a series resistor that size would be no protection at all. Static charges are in the range of a few thousand volts. A 100 Ohm resistor would pass a few tens of amperes for as long as the charge lasted, and that's far more than the chip can withstand. In order to be useful for static protection, a series resistor would have to be in the hundreds of kOhm, bringing the maximum current down to what the chip's internal diodes can support. Maybe a little less if you're adding diodes of your own, and you trust them to switch faster and have less voltage drop than the chip's own.
The resistor is not the protection part, the diodes are. The resistor just current limits what goes to the diodes.

Just because they say the chip is 'protected' that doesn't mean that it's a good idea to not protect the inputs. In some cases the chip degrades slightly each time it gets zapped but still works until it gets zapped that 100th (or whatever) time. Also from the On Semi datasheet there is the however clause.
This device contains protection circuitry to guard
against damage due to high static voltages or electric
fields. However, precautions must be taken to avoid applications
of any voltage higher than maximum rated
voltages to this high−impedance circuit. For proper operation,
Vin and Vout should be constrained to the range
VSS ≤ (Vin or Vout) ≤ VDD.
Unused inputs must always be tied to an appropriate
logic voltage level (e.g., either VSS or VDD). Unused outputs
must be left open.
User avatar
mskala
Super Deluxe Wiggler
Posts: 2750
Joined: Thu Mar 27, 2014 7:33 am
Location: Toronto
Contact:

Post by mskala »

emmaker wrote:
along with protection diodes to the power rails used by the chips
If, as Repeater says, these chips are able to withstand static anyway, then it doesn't matter. But if static were a serious issue, then a series resistor that size would be no protection at all. A 100 Ohm resistor would pass a few tens of amperes for as long as the charge lasted, and that's far more than the chip can withstand.
The resistor is not the protection part, the diodes are. The resistor just current limits what goes to the diodes.
Indeed, but that's the point - because the voltages are so high, a resistor that size does not meaningfully limit the current. It would have to have a very much larger resistance before it would make any difference compared to just the diodes alone.
North Coast Synthesis Ltd.
Twitch stream (Mondays, 3pm Eastern)

If you tell me that your goal is systemic change toward radical acceptance, and I see that you treat those you perceive as lesser-than with the same kind of scorn and derision that pushed me toward this insular little subculture where I feel comfortable [. . .] then you’ve successfully convinced me that your acceptance is not radical and the change you want not systemic. - "When Nerds Collide"
User avatar
glennfin
Ultra Wiggler
Posts: 873
Joined: Sun Apr 19, 2015 1:19 pm
Location: Winston Salem, NC
Contact:

Post by glennfin »

"transorbs" are your friend. :yay:
User avatar
glennfin
Ultra Wiggler
Posts: 873
Joined: Sun Apr 19, 2015 1:19 pm
Location: Winston Salem, NC
Contact:

Post by glennfin »

I count 10 unconnected/floating pins... they don't have to be "inputs" to be susceptible to an ESD event.

Repeater wrote:
glennfin wrote:There's a good chance that repeatedly touching unprotected floating pins/connections on a Cmos device will damage the device. :ripbanana:
Generally that's the conventional wisdom, but this is a special case...

The only "floating" input in this circuit is the Signal Input (pin 14)... but it's not a digital logic gate! There's a linear amplifier inside that tries to amplify whatever you plug into it up to logic levels to drive the phase comparators. Generally, most people would want to amplify signals externally instead of using this feature of the CD4046. Don Lancaster writes about this in the CMOS Cookbook: "Linear operation causes extra amplitude-variation sensitivity, jitter, tearing and generally poor noise immunity." I believe that this irregularity is the source of much of the interesting behavior in this circuit.

Anyway, you don't need a pull-down or pull-up resistor there. :tu:
User avatar
ehafh
Wiggling with Experience
Posts: 274
Joined: Thu Jan 22, 2015 11:07 pm
Location: illinois, usa
Contact:

Post by ehafh »

thanks for sharing, this looks neat.
might have to build one or two!
User avatar
igormpc
Wiggling with Experience
Posts: 381
Joined: Tue Feb 03, 2009 1:16 pm
Location: brazil

Post by igormpc »

Repeater wrote: The additional $.50 in parts buys you stereo operation and opportunities for cross-modulation.
how can i do it? :)
User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Post by Repeater »

Let's get empirical. I wonder how many people who are certain that this circuit will fail have actually built one and confirmed their suspicions. So far, there have been four successful builds and no CD4046s harmed. My original unit has been working for 2 months with almost daily usage. I'll update this post and keep a tally as long as people respond.

If you have the time to take 5 minutes to post, you have time to breadboard a circuit with 4 components, right? Perhaps we'll all learn something.

If not, this is a $1 circuit. Thanks for playing! :tu:
User avatar
Repeater
Phantom Powers
Posts: 783
Joined: Sun Oct 03, 2010 3:14 am
Location: Rochester, NY

Post by Repeater »

igormpc wrote:
Repeater wrote: The additional $.50 in parts buys you stereo operation and opportunities for cross-modulation.
how can i do it? :)
The schematic in the first post has two outputs. Pan them left and right or use a pair of amps and you're good to go.
User avatar
mskala
Super Deluxe Wiggler
Posts: 2750
Joined: Thu Mar 27, 2014 7:33 am
Location: Toronto
Contact:

Post by mskala »

Repeater wrote:Let's get empirical. I wonder how many people who are certain that this circuit will fail
Don't put words in my mouth. I asked a question. Nobody here is "certain this will fail."

Riding a motorcycle without a helmet is something many people have done without problems, too. That doesn't make it a good idea. And encouraging newbies in particular to do it is likely to draw some concern from experienced motorcyclists who are still alive.

You posted a design that does not conform to industry-standard ESD practices. You say it hasn't failed for you, yet. I'm sure that is true. But it doesn't mean you're exempt from reasonable questions about its reliability.

At least you're not selling them. (EDIT: well, in 2020, now you are.)
Last edited by mskala on Sat Feb 29, 2020 1:18 pm, edited 1 time in total.
North Coast Synthesis Ltd.
Twitch stream (Mondays, 3pm Eastern)

If you tell me that your goal is systemic change toward radical acceptance, and I see that you treat those you perceive as lesser-than with the same kind of scorn and derision that pushed me toward this insular little subculture where I feel comfortable [. . .] then you’ve successfully convinced me that your acceptance is not radical and the change you want not systemic. - "When Nerds Collide"
User avatar
EATyourGUITAR
has no life
Posts: 8446
Joined: Tue Aug 31, 2010 12:24 am
Location: Providence, RI, USA

Post by EATyourGUITAR »

I say kill the chips and let them burn as long as you record the audio everything will be fine.
WWW.EATYOURGUITAR.COM <---- MY DIY STUFF
User avatar
fluxmonkey
Super Deluxe Wiggler
Posts: 1921
Joined: Sat Oct 18, 2008 10:05 pm
Contact:

Post by fluxmonkey »

i propose naming this circuit "doomed to fail" - consider what a catchy name did for th atari punk console. and ultimately, arent we all dtf? nobody lives forever.

to the breadboard, batman!
www.fluxmonkey.com

BUILDER FOR HIRE - kits or custom, email me with your needs
Post Reply

Return to “Music Tech DIY”