| Author |
Message |
gasboss775
Joined: Jan 02, 2016
Posts: 217
Location: Scotland
|
 Posted: Tue Apr 11, 2017 5:32 am Post subject:
|
  |
|
I wanted to try out the minimal configuration that would yield usable results. The attached images show the simulation results and schematic for a very basic VCA implementation which seems to work well ( at least on the simulator! )
Only works with Digital Signal Sources
The Pot adjusts the decay time.
The output is highlighted in green, the 2.8 Mohm represents the input impedance of a jfet buffer / mixer.
| Description: |
|
| Filesize: |
68.86 KB |
| Viewed: |
741 Time(s) |
| This image has been reduced to fit the page. Click on it to enlarge. |
|
| Description: |
|
| Filesize: |
368.43 KB |
| Viewed: |
782 Time(s) |
| This image has been reduced to fit the page. Click on it to enlarge. |
|
|
|
|
Back to top
|
|
 |
gasboss775
Joined: Jan 02, 2016
Posts: 217
Location: Scotland
|
|
|
Back to top
|
|
|
richardc64
Joined: Jun 01, 2006
Posts: 679
Location: NYC
Audio files: 26
|
|
|
Back to top
|
|
|
gasboss775
Joined: Jan 02, 2016
Posts: 217
Location: Scotland
|
| Posted: Tue Apr 11, 2017 10:49 pm Post subject:
|
|
|
| Thanks RichardC64, I was thinking about a drum circuit like that but not sure on component values, I'll definitely give this one a try! |
|
|
Back to top
|
|
|
gagarin
Joined: Mar 17, 2014
Posts: 1
Location: vilnius
|
| Posted: Thu Oct 05, 2017 3:46 am Post subject:
Re: Diode VCA & simple EG |
|
|
| richardc64 wrote: | | gasboss775 wrote: | I tried this version of the diode VCA today. ( see attached )
R3 was found to be necessary to avoid signal breakthrough. |
Without a resistor path to ground at the VCA output -- that is, if it's capacitor coupled -- the right-hand diode can be omitted, as below. |
How can I change attack time? What will be if I will use sine or saw as input signal? |
|
|
Back to top
|
|
|
gasboss775
Joined: Jan 02, 2016
Posts: 217
Location: Scotland
|
|
|
Back to top
|
|
|
airfrankenstein
Joined: Jan 10, 2010
Posts: 62
Location: france
|
Posted: Tue Apr 16, 2019 1:46 am Post subject:
Re: A VCA of sorts
Subject description: and simple EGs |
|
|
Hi there,
So these simple circuits are entirely passive ?
| richardc64 wrote: | At some point you'll want to hear the results of interconnecting all these digital circuits, and you'll probably want some dynamic control of the amplitude. The first circuit provides amplitutude control of digital waveforms without resorting to OpAmps, OTAs, or (ugh) cmos in linear mode.
Basically, as CV rises, the rectangular wave from the digital output to be heard "stands up" at the junction of the two diodes and passes through the 100K resistor and the coupling capacitor. This method was used in paia's Stringz-n-Thingz and a similiar technique was used in their Cosmic EGG.
Two simple EGs are shown, which don't really need much explanation. Select pot and cap values for the desired durations. The Gate Inputs should probably be buffered by an AND gate with both inputs tied together. If the output is to be routed many places, it can be buffered by a single-supply OpAmp such as the LM324. |
|
|
|
Back to top
|
|
|
gabbagabi
Joined: Nov 29, 2008
Posts: 652
Location: Berlin by n8
Audio files: 23
|
| Posted: Thu Apr 18, 2019 5:12 am Post subject:
|
|
|
i was forced to remember something as i saw the simulation screenshot
| Description: |
|
| Filesize: |
57.98 KB |
| Viewed: |
508 Time(s) |
| This image has been reduced to fit the page. Click on it to enlarge. |
|
| Description: |
|
| Filesize: |
63.03 KB |
| Viewed: |
487 Time(s) |
| This image has been reduced to fit the page. Click on it to enlarge. |
|
|
|
|
Back to top
|
|
|
Steveg
Joined: Apr 23, 2015
Posts: 184
Location: Perth, Australia
|
Posted: Mon Apr 22, 2019 3:58 pm Post subject:
Re: A VCA of sorts
Subject description: and simple EGs |
|
|
| airfrankenstein wrote: | Hi there,
So these simple circuits are entirely passive ?
|
Welcome airfrankenstein,
No, they all have active components such as the transistors.
Passive is usually reserved for circuits that have no powered components.
Cheers,
Steveg |
|
|
Back to top
|
|
|
|
Forum index » DIY Hardware and Software » Lunettas - circuits inspired by Stanley Lunetta
FAQ
Calendar
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
Chat Room
