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 
go to the radio page Live at electro-music.com radio 1 Please visit the chat
poster
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
CGS77 - Serge VCF
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [17 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
drapdap



Joined: Oct 11, 2004
Posts: 204
Location: London
Audio files: 1
G2 patch files: 1

PostPosted: Thu Dec 17, 2009 6:02 am    Post subject: CGS77 - Serge VCF
Subject description: news from 1973
Reply with quote  Mark this post and the followings unread

Thank you sir Stone!

im just staring at the schemo... feels like an early xmas present.

http://www.cgs.synth.net/modules/cgs77_vcf.html
Back to top
View user's profile Send private message
LetterBeacon



Joined: Mar 18, 2008
Posts: 454
Location: London, UK

PostPosted: Thu Dec 17, 2009 1:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Wow, very exciting!

Are there any demos available?
Back to top
View user's profile Send private message
drapdap



Joined: Oct 11, 2004
Posts: 204
Location: London
Audio files: 1
G2 patch files: 1

PostPosted: Thu Dec 17, 2009 2:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

LetterBeacon wrote:
Wow, very exciting!

Are there any demos available?


probably as it seems this is an the old serge classic, might be tons of records this one is featured on.

http://www.cgs.synth.net/synth/serge/vcf.html

this one, plus a buffer...
this might be a state variable filter?
beautiful stuff ...
Back to top
View user's profile Send private message
LetterBeacon



Joined: Mar 18, 2008
Posts: 454
Location: London, UK

PostPosted: Sun Dec 27, 2009 4:59 am    Post subject: Reply with quote  Mark this post and the followings unread

I'd just like to confirm something:

To use the TL074 buffer section I would, instead of wiring as shown on the wiring diagram, connect the HP BP and LP outputs to the TL074 inputs and then the TL074 outputs to the sockets?
I don't understand the setting up instructions:
Quote:
Adjustments on the vcf board are basic. Set trimmer so that the VCF's center frequency as at an appropriate pitch.

I don't understand what an appropriate pitch is!
Back to top
View user's profile Send private message
widdly



Joined: Jun 25, 2007
Posts: 268
Location: singapore
G2 patch files: 2

PostPosted: Tue Dec 29, 2009 10:42 pm    Post subject: Reply with quote  Mark this post and the followings unread

The trimmer just adds an offset voltage to the frequency CV summer. If you set the Cutoff knob to the middle you can change what frequency the middle will be by changing the trimmer.

I don't know what real serges use but looking at moog or arp front panels show the filter cutoff centre is usually 500Hz so that would be a good place to start.

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

Last edited by widdly on Thu Aug 05, 2010 10:00 pm; edited 1 time in total
Back to top
View user's profile Send private message
fluxmonkey



Joined: Jun 24, 2005
Posts: 708
Location: cleve

PostPosted: Fri Feb 12, 2010 5:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

hmm... just noticed this on kens page for the Serge filter: "Those assembling the Euro version of this module..."

hotdamn.

_________________
www.fluxmonkey.com
Back to top
View user's profile Send private message
jnuaury



Joined: Feb 28, 2008
Posts: 161
Location: chicago
Audio files: 9

PostPosted: Thu Feb 18, 2010 9:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

bbob wrote:
hmm... just noticed this on kens page for the Serge filter: "Those assembling the Euro version of this module..."

hotdamn.


the full quote says

"Those assembling the Euro version of this module will need to substitute two of the regular pots and the spst switches for combined units available from Mouser. P/N: 313-1600F-50k "

this is probably copy-pasted over from the VCS page
unfortunately the VCF has no switches so theres no need for theres mouser parts so theres probably not a euro board planned....

_________________
az/gde
Flickr
YouTube
Back to top
View user's profile Send private message AIM Address
andrewF



Joined: Dec 29, 2006
Posts: 1176
Location: australia
Audio files: 4

PostPosted: Thu Feb 18, 2010 10:33 pm    Post subject: Reply with quote  Mark this post and the followings unread

jnuaury wrote:

unfortunately the VCF has no switches so theres no need for theres mouser parts so theres probably not a euro board planned....

there can be a switch -
also from the VCF page - "A DPDT switch can be added to short points F and G to 0V. Doing this will switch the filter into low-frequency mode, as per the VCFX (for CV filtering etc.). While the original Serge boards had this function, it is doubtful it was ever brought out to the panel. "

this is a worthwhile mod, CV filtering is cheeeezeeey and a rather unusual feature for a VCF.
Back to top
View user's profile Send private message Visit poster's website
macumbista



Joined: Sep 12, 2007
Posts: 398
Location: berlin
Audio files: 3

PostPosted: Sun Jul 25, 2010 9:40 am    Post subject: Reply with quote  Mark this post and the followings unread

Built a pair of these a few months ago, just want to chime in that they are SWEEEEEET and well worth the time and expense. You can probably hear plenty of this filter in these tracks....
_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
macumbista



Joined: Sep 12, 2007
Posts: 398
Location: berlin
Audio files: 3

PostPosted: Sun Oct 03, 2010 1:52 am    Post subject: Reply with quote  Mark this post and the followings unread

Is anyone else finding that the CV inputs go wild really quickly? Seems like way more than 1V/Oct. Just a little tweak off center in either positive or negative direction and the modulation is extremely wide. I'm using 25K lin pots instead of the listed 20K, but that shouldn't account for such an extreme amount of input.
_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
j.dilisio



Joined: May 19, 2009
Posts: 200
Location: baltimore

PostPosted: Tue Oct 12, 2010 11:45 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Macumbista, what's the password to unrar that Serge Mix?
_________________
DRONEGOAT
Back to top
View user's profile Send private message
macumbista



Joined: Sep 12, 2007
Posts: 398
Location: berlin
Audio files: 3

PostPosted: Tue Oct 12, 2010 3:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

j.dilisio wrote:
Hey Macumbista, what's the password to unrar that Serge Mix?


It's in the blog post, just below the DL links... "orpheusmachine"

_________________
Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
macumbista.net
Back to top
View user's profile Send private message
j.dilisio



Joined: May 19, 2009
Posts: 200
Location: baltimore

PostPosted: Tue Oct 12, 2010 5:27 pm    Post subject: Reply with quote  Mark this post and the followings unread

Aaah! So it was right in front of me.
Cheers

_________________
DRONEGOAT
Back to top
View user's profile Send private message
xi-boy



Joined: Dec 16, 2008
Posts: 18
Location: germany

PostPosted: Mon Oct 15, 2012 7:27 am    Post subject: Reply with quote  Mark this post and the followings unread

macumbista wrote:
Is anyone else finding that the CV inputs go wild really quickly? Seems like way more than 1V/Oct. Just a little tweak off center in either positive or negative direction and the modulation is extremely wide. I'm using 25K lin pots instead of the listed 20K, but that shouldn't account for such an extreme amount of input.


this filter has become one of my favorites
its specially brilliant for pinging sounds
but probably because of its wide cv range (?) its resonance loves to freak out ;-(
also the bipolar attenuator dosent close completely
i actually would prefer a uni polar attenuator
any idea how to make this filter more controllable ?
Back to top
View user's profile Send private message
LetterBeacon



Joined: Mar 18, 2008
Posts: 454
Location: London, UK

PostPosted: Fri Mar 29, 2013 10:01 am    Post subject: Reply with quote  Mark this post and the followings unread

widdly wrote:
The trimmer just adds an offset voltage to the frequency CV summer. If you set the Cutoff knob to the middle you can change what frequency the middle will be by changing the trimmer.

I don't know what real serges use but looking at moog or arp front panels show the filter cutoff centre is usually 500Hz so that would be a good place to start.


What setting are people using for their filters? How are you guys measuring the frequency that you're setting it at?
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 461
Location: germany
Audio files: 10

PostPosted: Mon Jun 29, 2015 12:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

digging that old thread out as i still need a VCF for my 4th "synthcase"

already have plenty of others in my other cases but i definitely wanted to build a serge VCF too...

As i don't have those gain cells for the VCQ VCF i'm stuck to this one...

have all material form the BOM except the J201...

can i substitute them with 2n3819 or 2SK30 which are also N-Channel FET's?
would this work?

Any advice would be welcome...

cheers Bastian

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 461
Location: germany
Audio files: 10

PostPosted: Thu Jul 02, 2015 10:07 am    Post subject: Reply with quote  Mark this post and the followings unread

well, can answer my last question now on my own... yes it works with 2SK30... probably not as in the original but i think it Sound smooth and fine...
what makes me wonder is that my filter does self-oscillate without those modifications Ken mentioned on his site... hmm... and the volume doesn't drop either it increases a lot...

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [17 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 » 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


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