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nisios
Joined: Sep 02, 2006 Posts: 49 Location: Lisboa - Portugal
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Posted: Sun Oct 08, 2006 9:30 pm Post subject:
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Hi...
I breadboarded this using 9v.
i was thinking of making a pedal but with only 9v i get lots of bleed throu.
Is there any way of making this sound good with 9v?
I used voltage division to power the 2 ics.
The cmos is using 4.5v.
the ad781 is getting + 4.5 and - 4.5.
maybe the relation between the 2 voltages is messing this....no?
you used 24v p to p and 5v to cmos. So ... a pretty diferent relation......but with only 9 to mess arround theres no much room to drop the cmos voltage.
Any way this thing is great.....only the annoying oscillation.. _________________ Why is the dove a symbol of peace?
The pillow has a lot more feathers without that dangerous beak. |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
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Posted: Mon Oct 09, 2006 1:48 am Post subject:
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Cool that you've tried like this -- though I think 9v will almost certainly be insufficient and especially with the powering of the 40106 for clocking. Someone else has just been emailing me about trying it out with two 9v batteries (so as to create a simple bipolar supply) -- I think this has a greater chance of working out - I'll let you know when I hear some news from him.. _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
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Posted: Mon Oct 09, 2006 2:30 am Post subject:
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You could also try one of those little charge pump chips.
http://www.geofex.com/circuits/+9_to_-9.htm _________________ What makes a space ours, is what we put there, and what we do there. |
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nisios
Joined: Sep 02, 2006 Posts: 49 Location: Lisboa - Portugal
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Posted: Mon Oct 09, 2006 6:45 am Post subject:
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Thanks.
I think i will try the charge pump......just have to see if i can find one of those ic's in my local shop. _________________ Why is the dove a symbol of peace?
The pillow has a lot more feathers without that dangerous beak. |
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modularkomplex
Joined: Feb 14, 2007 Posts: 11 Location: germany
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Posted: Sat Mar 03, 2007 12:06 pm Post subject:
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Hi,
I did a simple LF398-version of the circuit. Works fine.
cheers,
Mike
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Last edited by modularkomplex on Wed Sep 05, 2007 10:42 am; edited 2 times in total |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
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G2 patch files: 1
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Posted: Sun Mar 04, 2007 5:24 am Post subject:
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Nice work! Well done & thanks for posting!
I'd been wondering on doing one with the LF398 - its edge triggered, right? So no need to make the trigger signal into a really narrow pulse.. _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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modularkomplex
Joined: Feb 14, 2007 Posts: 11 Location: germany
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Posted: Sun Mar 04, 2007 5:44 am Post subject:
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Yes, no need of a narrow pulse here. And the other difference is the need of a hold-cap - the 100nF between the ICs. This should be much smaller than the stated 100nF, I think 0.1-10nF would perform better. I still have to do some experiments here.
Mike
PS: I've tested various values for the hold-cap. Best audible results are with 4,7nF. 1nF and lower will result in a whistling background-sound (but that could be from the used NPO - had no foil-caps left at these values). I've updated the above posted pictures. Last edited by modularkomplex on Sun Mar 04, 2007 6:09 am; edited 1 time in total |
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v-un-v
Janitor
Joined: May 16, 2005 Posts: 8933 Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Sun Mar 04, 2007 6:06 am Post subject:
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Hey Mike this is great!! Thanks very much for posting these and,
to electro-music.com too of course! _________________ ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
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Photon
Joined: Mar 22, 2005 Posts: 363 Location: Boston
Audio files: 1
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Posted: Thu May 10, 2007 5:42 pm Post subject:
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I just stumbled across this:
The Malgorithm, a voltage-controlled bit depth and sample-rate reducer module.
http://www.youtube.com/watch?v=ZMxmxuA4LZg
website here:
http://www.theharvestman.org/
he's got two other modules finished as well, the "zorlon cannon"- pitched noise and gates, and the "hertz donut", a digital oscillator
really cool sounding stuff and worth a look |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
Audio files: 1
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bigtex
Joined: Mar 30, 2006 Posts: 323 Location: Cupertino, California
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Posted: Sun Jul 22, 2007 7:50 pm Post subject:
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I woke up this morning with an idea in my head. I've finally solved a problem that has been bugging me ever since this thread started.
For a long time I've been wanting to make an effect with continuously variable amplitude quantization, but I hadn't come up with a good way of doing it that didn't involve analog to digital to analog conversion. A sample and hold works great for time quantization (sampling) but doesn't do anything to reproduce the effects of bit depth (aka "bitcrusher").
The problem with fixed bit depths is that you get fixed steps of amplitude quantization. 4-bit audio has 16 amplitude steps, and changing to 3-bit or 5-bit will jump to a different number of steps and a different sound. Wouldn't it be nice to smoothly scale the staircase to dial in just the right sound or slowly modulate the quantization?
The solution: comparators and two sample and hold stages!
This operates very much like a ramp-compare ADC but without the need for precision timing. The basic principle is that a sawtooth wave at a very high frequency is used as the reference input to a comparator, so every time the input audio and the sawtooth cross each other, the comparator changes state. This state change is used to drive the S&H chip's clock input (and National's LF398 is edge triggered, as pointed out before).
OK, so now we have audio being sampled every time it crosses paths with a high frequency sawtooth wave. Great. But that's no better than a regular S&H other than the slight skew between successive samples due to the sawtooth-wave based triggering. How does this get me adjustable amplitude quantization?
Add another stage before this where the sawtooth wave is, itself, quantized by an even higher frequency square wave. So if the sawtooth being used to quantize the audio was 10kHz (slightly audible ringing would be produced) then that sawtooth should be quantized by a, let's say, 100kHz square wave using another S&H chip. Now the 10kHz sawtooth is divided into a ladder. Turn the 100kHz wave up or down in frequency and you get a different number of steps.
Now that we have a staircase wave, let's go back to the audio being quantized. As I said before, every time the audio and sawtooth wave cross each other, a sample is taken. Now that we have a staircase wave instead of a sawtooth, each of those samples will be taken at specific amplitudes defined by the shape of the staircase wave.
Adjusting the square wave will change how many steps the sawtooth wave is divided into. Adjusting the sawtooth wave's frequency will change how frequently the input audio is divided into steps.
Smooth, infinitely adjustable quantization with variable amplitude steps and sampling rate. Just what I've always wanted.
SUMMARY:
Use existing S&H circuit to quantize a sawtooth wave.
Feed that into one input of a comparator.
Feed desired input audio into a buffer.
Feed first buffer output into second S&H chip.
Feed second buffer output into other input of comparator.
Use comparator output as clock of second S&H chip.
Enjoy the output greatly.
Any questions? (working on schematic and diagrams, here)
Edit: perhaps, depending on the speed of the ICs in use, it would be better for the 2nd S&H to sample the staircase wave instead of the audio input, just to be sure that the amplitude is correct and not dependent on the S&H grabbing the input audio at the right time... |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
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Posted: Wed Jul 25, 2007 5:33 pm Post subject:
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Hey Tex
(..I'm surprised no one else has commented on this exciting development!?)
Sounds ACE!
I don't fully understand your methods quite yet, but think I have an inkling what you're on about.
Let us know how yr investigations go! _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Thu Jul 26, 2007 2:43 am Post subject:
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I have been following this "exciting developement", and I'd love to comment on it, but unfortunately I have no idea what you're talking about!
Seriously though, I'm sure I'd get it if I just had the time to sit down and soak it up, (maybe the schematic will help), but with a head full of Klee and a lab full of bits, I just can't see the forrest for the trees at the moment. _________________ What makes a space ours, is what we put there, and what we do there. |
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trent saburo
Joined: May 27, 2007 Posts: 2 Location: ann arbor
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Posted: Fri Jul 27, 2007 1:49 pm Post subject:
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big tex is my hero |
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goodrevdoc
Joined: Sep 11, 2006 Posts: 288 Location: Philadelphia, PA
Audio files: 1
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Posted: Fri Jul 27, 2007 9:30 pm Post subject:
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Wow BigTex, that's pretty cool. Not sure I can say if I can see the trees or the forest, but I think I have a very rude crude idea of what's going on. Bug's circuit already has a spot planned in my modular, and I've some 398's on the way. Got to say I really like these off the beaten path modules, makes my noodling time more interesting, IMHO.
-justin |
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bigtex
Joined: Mar 30, 2006 Posts: 323 Location: Cupertino, California
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iorobyy
Joined: Sep 26, 2005 Posts: 65 Location: Italy
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Posted: Fri Sep 21, 2007 11:12 am Post subject:
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hi!
where i could buy some AD781? (better a european source) |
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loss1234
Joined: Jul 24, 2007 Posts: 1536 Location: nyc
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synthmonger
Joined: Nov 16, 2006 Posts: 578 Location: flada
Audio files: 3
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Posted: Wed Aug 27, 2008 7:28 am Post subject:
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How bad does the oscillator bleed through for you guys? Theres alot of crackly noise that fades in and out on certain settings, it's kind of annoying ;x
I'm using a maxim charge pump and powering the board with +/- 9volts so I'm not sure if this has anything to do with it. I can't test it out on a bipolar 12 volt till I get home from work ;X Do you think this is the problemo? |
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synthmonger
Joined: Nov 16, 2006 Posts: 578 Location: flada
Audio files: 3
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Posted: Thu Aug 28, 2008 6:34 am Post subject:
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nm fixed it dang wire poped out of the board. I need to get my eyes checked |
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noisedeputy
Joined: Nov 15, 2008 Posts: 17 Location: Boston, MA
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Posted: Sun Nov 16, 2008 9:08 am Post subject:
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bigtex wrote: | After drawing some waveforms and thinking about it I've tweaked the design a bit. Now I use three sample & hold ICs.
etc....
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what ever happened this development? |
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bigtex
Joined: Mar 30, 2006 Posts: 323 Location: Cupertino, California
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Posted: Sun Nov 16, 2008 3:28 pm Post subject:
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noisedeputy wrote: | bigtex wrote: | After drawing some waveforms and thinking about it I've tweaked the design a bit. Now I use three sample & hold ICs.
etc....
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what ever happened this development? |
Like just about everything in my life not related to my current job: nothing.
Sad but true. Since writing that my employment has taken over almost all of my time. I haven't even finished assembling all of the Blacet kits I bought over two years ago, let alone breadboard anything form my languishing idea notebook.
*sigh* |
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noisedeputy
Joined: Nov 15, 2008 Posts: 17 Location: Boston, MA
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Posted: Sun Nov 16, 2008 3:40 pm Post subject:
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that's no fun to hear, let us know if you ever eventually get to work on this idea again then I suppose. |
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softfin
Joined: Oct 11, 2006 Posts: 271 Location: Far in the north
Audio files: 1
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Posted: Sat Feb 07, 2009 10:32 am Post subject:
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Ok. I just have to break the silence in this topic
I had a fully stuffed 398-version of the Bug Crusher laying on the table for at least a year, but today I finally wired it up and ... Works great. It sounds nice and dirty as expected.
There's a constant ringing sound going on which is audible with a low level signal and when there is nothing connected to the input. I suppose it is normal in this circuit(?)
Anyway, I find this a very useful module for various things. Thanks a lot to Tom for the design (and modularkomplex for the stripboard layout)! |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
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Posted: Sun Feb 08, 2009 7:22 am Post subject:
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Great stuff!
You should be able to decrease any background clocking noise by narrowing the trigger pulses (though I don't know particularly with the 398 'cos it maybe does things internally unlike the AD781).
Hey - and remember that you may also be able to set things just slightly differently and use it as a standard Sample & Hold module (ie running at low freqs).
Edit - also note that you should be careful with the wiring -- bad wiring can mean crosstalk which could be where your bad-tone-bleeds are coming from. _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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