electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software
Is there such a thing as a digitally controlled ADSR?
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [14 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
jackdamery



Joined: Apr 26, 2010
Posts: 75
Location: UK

PostPosted: Thu Jan 17, 2013 11:53 am    Post subject: Is there such a thing as a digitally controlled ADSR? Reply with quote  Mark this post and the followings unread

I was wondering if any chips or designs existed for a digitally controlled ADSR. I'd like to stick such a thing on my vco to save building one from components.
Back to top
View user's profile Send private message
jackdamery



Joined: Apr 26, 2010
Posts: 75
Location: UK

PostPosted: Thu Jan 17, 2013 11:55 am    Post subject: Reply with quote  Mark this post and the followings unread

Now I think about it, I suppose in essence it would be a digitally controlled amplifier.
Back to top
View user's profile Send private message
minisystem



Joined: Nov 16, 2012
Posts: 35
Location: Toronto

PostPosted: Thu Jan 17, 2013 8:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

Do you mean something like this?

http://www.electricdruid.net/forums.html?page=projects.envgen7

It's an ADSR implemented in software on a microcontroller. Takes gate/trigger as input and outputs a control voltage based on ADSR settings.
Back to top
View user's profile Send private message
bubzy



Joined: Oct 27, 2010
Posts: 594
Location: United Kingdom
Audio files: 64

PostPosted: Fri Jan 18, 2013 12:07 am    Post subject: Reply with quote  Mark this post and the followings unread

ive recently been messing about with a DAC on an arduino after reading elmegils post on the arduino subforum. with this method its quite attainable, and very configurable too.
_________________
_Richard_ Smile
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 2177
Location: Chicago
Audio files: 16

PostPosted: Fri Jan 18, 2013 6:22 am    Post subject: Reply with quote  Mark this post and the followings unread

Speaking of which, I was just working on building a shield that has two MCP4922's and a few op amps for buffers. My original thought was to proceed on some of the MIDI->CV speculation I was doing a few months back, but I realized as I was going along that basically I'm creating a shield that could be used for envelopes or any other set of 4 CVs and two square signals (gate & trigger for the MIDI application). Quadrature LFO came to mind too.

Unfortunately it's just a proto shield with wires running every which way; I have not made any headway with eagle doing actual boards, but I will share the circuit when I'm done (it's really pretty simple, so...).
Back to top
View user's profile Send private message
rjh



Joined: Jan 20, 2013
Posts: 12
Location: Sweden

PostPosted: Sun Jan 20, 2013 5:13 am    Post subject: Reply with quote  Mark this post and the followings unread

Not sure about digitally controlled amplifiers, but there are digital controlled potentiometers (SPI or I2C). I haven't experimented with it but I guess it could potentially be used in a simple op-amp amplifier configuration to create a DCA. I know at least Microchip and Analog Devices makes them.
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 2177
Location: Chicago
Audio files: 16

PostPosted: Sun Jan 20, 2013 7:27 am    Post subject: Reply with quote  Mark this post and the followings unread

I bought some of the microchip ones, 10K, from SparkFun a while back. It's an MCP4131-103. They also have 5k, 50k, and 100k variants.

One unfortunate thing is they only have an operating voltage up to 5.5V which will make them more difficult to use in the typical 12V or 15V synth circuit.
Back to top
View user's profile Send private message
rjh



Joined: Jan 20, 2013
Posts: 12
Location: Sweden

PostPosted: Sun Jan 20, 2013 8:05 am    Post subject: Reply with quote  Mark this post and the followings unread

elmegil wrote:

One unfortunate thing is they only have an operating voltage up to 5.5V which will make them more difficult to use in the typical 12V or 15V synth circuit.


That's good to know. Looked up some other ones and it seam to be the same. Maxim makes a few that can handle 8v but not more. Though I'm guessing if you're working in the digital domain to begin with you're probably working in the 0-5v range.
Back to top
View user's profile Send private message
bubzy



Joined: Oct 27, 2010
Posts: 594
Location: United Kingdom
Audio files: 64

PostPosted: Sun Jan 20, 2013 8:32 am    Post subject: Reply with quote  Mark this post and the followings unread

thats not a problem at all,
use an op amp and boost the voltage up 3x
0-5 becomes 0-15.

_________________
_Richard_ Smile
Back to top
View user's profile Send private message
rjh



Joined: Jan 20, 2013
Posts: 12
Location: Sweden

PostPosted: Sun Jan 20, 2013 8:43 am    Post subject: Reply with quote  Mark this post and the followings unread

more importantly scale / offset the signal first. Not very hard, but inconvenient Smile
Back to top
View user's profile Send private message
JovianPyx



Joined: Nov 20, 2007
Posts: 1988
Location: West Red Spot, Jupiter
Audio files: 224

PostPosted: Sun Jan 20, 2013 1:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

digital stuff is tending toward lower and lower voltages. I see lots of applications where 3.3volts is the standard. I see more and more digital parts that are 2.2v. Lower voltage digital circuits tend to use less power and are usually faster because the signals have less "distance" to travel when changing state.

As bubzy said, when it gets to a place where the outside world wants to see higher voltages, then amplify.

I mess with dsPICs at 3.3 volts. The DACs barely output 1 volt. So I amplify. Some people freak out about amplifying because there's always a bit of noise - but hey show me any noise free circuit and you win a prize. If the noise is low level enough that you don't hear it, then it doesn't matter. Yeah, it's another part to purchase and solder. Yep. Oh well. With SMT, you can cram all kinds of crap on a board now unlike the old days when you could actually see the parts you're soldering...

_________________
FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.
Fruit flies when you're having fun.
BTW, Do these genes make my ass look fat?
corruptio optimi pessima
Back to top
View user's profile Send private message Visit poster's website
elmegil



Joined: Mar 20, 2012
Posts: 2177
Location: Chicago
Audio files: 16

PostPosted: Sun Jan 20, 2013 4:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

Didn't mean to say they were a LOT more difficult Very Happy
Back to top
View user's profile Send private message
JovianPyx



Joined: Nov 20, 2007
Posts: 1988
Location: West Red Spot, Jupiter
Audio files: 224

PostPosted: Sun Jan 20, 2013 5:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

To answer the OP's question "Is there such a thing as a digitally controlled ADSR?"

The PAiA Fatman has a hybrid digital/analog ADSR and ASR. The ramp generating parts are capacitors and resistors while the level sensing logic parts are actually code running in the MIDI controller microprocessor.

I have also personally written code to be an ADSR within a digital design without any analog help.

_________________
FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.
Fruit flies when you're having fun.
BTW, Do these genes make my ass look fat?
corruptio optimi pessima
Back to top
View user's profile Send private message Visit poster's website
The Real MC



Joined: Jun 20, 2008
Posts: 62
Location: Painted Post NY

PostPosted: Mon Jan 21, 2013 3:23 pm    Post subject: Reply with quote  Mark this post and the followings unread

The Moog Source has digitally controlled ADSRs, OTA based circuits using only two CVs for transition time and level.

http://www.retrosynth.com/~analoguediehard/studio/keyboards/moog_source/index.html#technical
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [14 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use