electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
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 
Live streaming at radio.electro-music.com

  host / artist show at your time
  Asheville electro-music festival live stream

poster

Please visit the chat
 Forum index » DIY Hardware and Software
Gauging interest, VCA Rider, flexible VCA pcbs
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [9 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
peng



Joined: Feb 23, 2006
Posts: 109
Location: Chicago
Audio files: 2

PostPosted: Thu Aug 30, 2012 12:01 pm    Post subject: Gauging interest, VCA Rider, flexible VCA pcbs
Subject description: simple, small, quality VCA
Reply with quote  Mark this post and the followings unread

I want to see if there is any interest in DIY versions of my VCA Rider pcb.
These are bare pcbs - $10 each.
If there is interest I will write up detailed documentation and offer these for sale.

The VCA core is a Mike Sims design from EDN magazine. It uses both halves of a 13700(or 13600) to form one VCA. Why two sides to form one VCA? Less noise and MUCH less CV feedthrough.

The boards can be built in a variety of ways to suit your needs.
Add a VCA to your custom builds. Add a VCA to your DotCom modules (mounting holes match the small DotCom pcbs so you can stack it). Make a separate VCA module. Build a xfade or pan with two boards.

Pcb offers these options:

3 input summer, pre-VCA stage.
Output stage includes an extra input to mix in a signal post-VCA.
2 CV inputs
Offset/Intial/Gain/Bias control (whatever you want to call it!)
2 input "free" summing stage. Use this to invert CV or whatever else you can think of.
Reverse power protection.
Other bells and whistles.

Board is 1.9" x 2.9"

Any interest?

Thanks,
p.


VCA Rider pcb full 25.jpg
 Description:
 Filesize:  91.52 KB
 Viewed:  2602 Time(s)

VCA Rider pcb full 25.jpg


Back to top
View user's profile Send private message
Luka



Joined: Jun 29, 2007
Posts: 1002
Location: Melb.

PostPosted: Thu Aug 30, 2012 2:42 pm    Post subject: Reply with quote  Mark this post and the followings unread

yeah i might be keen on a bunch
maybe 4-5

_________________
problemchild
melbourne australia
http://cycleofproblems.blogspot.com/
http://www.last.fm/user/prblmchild
Back to top
View user's profile Send private message
fonik



Joined: Jun 07, 2006
Posts: 3812
Location: Germany
Audio files: 23

PostPosted: Thu Aug 30, 2012 3:12 pm    Post subject: Re: Gauging interest, VCA Rider, flexible VCA pcbs
Subject description: simple, small, quality VCA
Reply with quote  Mark this post and the followings unread

peng wrote:
Output stage includes an extra input to mix in a signal post-VCA.

so you can easily use this VCA for voltage controlled FX return? clever.

i would take 2pcs.

_________________
Posted Image, might have been reduced in size. Click Image to view fullscreen.
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)
Back to top
View user's profile Send private message Send e-mail Visit poster's website
peng



Joined: Feb 23, 2006
Posts: 109
Location: Chicago
Audio files: 2

PostPosted: Thu Aug 30, 2012 4:24 pm    Post subject: Re: Gauging interest, VCA Rider, flexible VCA pcbs
Subject description: simple, small, quality VCA
Reply with quote  Mark this post and the followings unread

fonik wrote:
peng wrote:
Output stage includes an extra input to mix in a signal post-VCA.

so you can easily use this VCA for voltage controlled FX return? clever.


That is a good idea!
I put that in there so I could wire in a second board to form a xfade.
Later I realized I could form a xfade with just one board:

two input jacks. IN1 to the VCA input. IN2 to the VCA input and to the extra inverting opamp stage. Inv opamp out to the "aux" input (post-VCA summer).

0V CV = inverted version of IN2 at the output
5V CV = IN1 at the output. IN2 cancels itself out.

The rub is that when IN2 is at the output it is an inverted form of the original IN2 signal.
Back to top
View user's profile Send private message
davidschwan



Joined: Jun 07, 2008
Posts: 7
Location: Silicon Valley

PostPosted: Fri Aug 31, 2012 7:32 pm    Post subject: Reply with quote  Mark this post and the followings unread

I'd be interested in 4.
Back to top
View user's profile Send private message
mcop



Joined: Apr 27, 2012
Posts: 40
Location: Brighton UK

PostPosted: Sat Sep 01, 2012 1:56 am    Post subject: Reply with quote  Mark this post and the followings unread

I'd be up for 2 boards.
Back to top
View user's profile Send private message Visit poster's website
ashleym



Joined: Aug 20, 2009
Posts: 181
Location: uk

PostPosted: Sat Sep 01, 2012 7:07 am    Post subject: Reply with quote  Mark this post and the followings unread

4 for me please. I am going with the theory that you can never have too many VCAs.
_________________
http://soundcloud.com/for-mash-get-ash
Back to top
View user's profile Send private message
Dave Kendall



Joined: May 26, 2007
Posts: 417
Location: England
Audio files: 3

PostPosted: Sat Sep 01, 2012 12:36 pm    Post subject: Reply with quote  Mark this post and the followings unread

Nice work Peng. Smile

That looks like a really versatile VCA PCB - Love the extra useful opamp bits, and can think of several uses straightaway.
I'll go for 4, maybe more if a run happens. There has been some occasional talk on [sdiy] and a few other places over the last few years about the doubling-up trick with 13700s. Really cool to see it implemented, and powerfully too! Hope the run happens!

cheers,
Dave

_________________
"Everything in moderation, including moderation"
Back to top
View user's profile Send private message
peng



Joined: Feb 23, 2006
Posts: 109
Location: Chicago
Audio files: 2

PostPosted: Mon Sep 03, 2012 12:36 pm    Post subject: Reply with quote  Mark this post and the followings unread

I just started a new thread for these.

http://electro-music.com/forum/post-368781.html#368781


I've had these in stock for a year now.
These started a couple years ago because I was adding VCAs and xfades to a lot of my custom jobs. I got a run of ten then a couple more runs of ten with little changes each time.
I made the pcb this size and put the mounting holes in the right place so it can stack/ride on top of the DotCom EG pcb (or any small DotCom pcb).

It can be used with other formats, of course.
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 [9 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
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


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