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
  mosc Chez Mosc - Twyndyllyngs Live
Please visit the chat
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
utility lfo
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 of 3 [58 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2, 3
Author Message
sonicwarrior



Joined: Dec 22, 2005
Posts: 236
Location: Cologne, Germany

PostPosted: Wed Jul 18, 2012 2:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

JingleJoe wrote:
that was a big mistake; not connecting the ground!


I was fooled by the banana jack systems. But I think they only work inside the same case this way and for connecting other cases they have a central ground connection. It seems this has to be used for the measuring equipment like oscilloscopes, too.
Maybe I should be happy I made this mistake on such a relatively simple module.
Back to top
View user's profile Send private message
tomcc



Joined: Dec 06, 2014
Posts: 4
Location: Australia

PostPosted: Sat Dec 06, 2014 8:08 pm    Post subject: Reply with quote  Mark this post and the followings unread

Sorry to drag up an old thread but I have almost completed this LFO to replace a Korg MS04 pedal that had 10v Peak to peak output that had a level control to vary the output level.
If I had the various outputs on a switch that then had a 10k pot after would this reduce the level enough or would I need something else to enable control to reduce the output enough so it would not overdrive the synths filter input??
The level control was useful as it could go from mild to full blown modulation of the Korg Trident filter.
Thanks for any help.
http://www.korganalogue.net/korgms/service/ms04/ms04schematic.jpg
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 180
Location: uptown

PostPosted: Thu Jan 08, 2015 5:49 am    Post subject: Reply with quote  Mark this post and the followings unread

tomcc wrote:
Sorry to drag up an old thread but I have almost completed this LFO to replace a Korg MS04 pedal that had 10v Peak to peak output that had a level control to vary the output level.
The level control was useful as it could go from mild to full blown modulation of the Korg Trident filter.
Thanks for any help.
http://www.korganalogue.net/korgms/service/ms04/ms04schematic.jpg



tomcc wrote:
If I had the various outputs on a switch that then had a 10k pot after would this reduce the level enough or would I need something else to enable control to reduce the output enough so it would not overdrive the synths filter input??


what synth are you referring to? what signals does it expect?

you could attenuate the signal by a fixed ratio with a pair of resistors or by using your potentiometer wired up as a voltage divider:

Posted Image, might have been reduced in size. Click Image to view fullscreen.
(source: http://www.doepfer.de/DIY/a100_diy.htm)

another option would be a combination, so you can use the full range of your pot without overloading the input.
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 180
Location: uptown

PostPosted: Thu Jan 08, 2015 5:51 am    Post subject: Reply with quote  Mark this post and the followings unread

oh, and welcome
Back to top
View user's profile Send private message
tomcc



Joined: Dec 06, 2014
Posts: 4
Location: Australia

PostPosted: Thu Jan 08, 2015 11:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

roglok wrote:
oh, and welcome

Thanks . the synth in question is a Korg Trident.
Back to top
View user's profile Send private message
roglok



Joined: Aug 28, 2010
Posts: 180
Location: uptown

PostPosted: Fri Jan 09, 2015 2:40 am    Post subject: Reply with quote  Mark this post and the followings unread

i didn't dig through the schematics, but according to this image it looks like the Trident filter inputs are designed to accept a +/-5V CV signal, which is what the Utility LFO provides:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

this means that no fixed attenuation is necessary. are you clear on how to wire the pot up as a voltage divider/variable attenuator?
Back to top
View user's profile Send private message
tomcc



Joined: Dec 06, 2014
Posts: 4
Location: Australia

PostPosted: Thu Jan 22, 2015 3:11 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for the info. The pedal I was using must of used the 10k pot as a voltage divider as per you diagram to vary the level it fed to the filter section.
So to enable the LFO to be used from subtle to full blown I need to add this after the output. I am not 100% sure how to wire this up.
Back to top
View user's profile Send private message
tomcc



Joined: Dec 06, 2014
Posts: 4
Location: Australia

PostPosted: Fri Feb 20, 2015 10:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

Just completed wiring this up with the 10k pot as a voltage divider and it works perfectly for the Korg Tridents input.
I can switch which waveform I want and this then goes through the pot and out to the synth. It's a long time since I used the synth with an external modulator and can't believe what I have missed. Totally changes the synth sound. All I need to do is find a simple noise and S&H circuit and I have the complete package I had 30 years ago.
Thanks Ken for a great design and for those that had added their experiences.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 of 3 [58 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
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