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

poster

Please visit the chat
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
CGS49 Dual CMOS filter - Odd problem with both filters
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [4 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
Flareless



Joined: Jan 16, 2016
Posts: 24
Location: Ontario, Canada

PostPosted: Mon Jan 23, 2017 11:08 am    Post subject: CGS49 Dual CMOS filter - Odd problem with both filters Reply with quote  Mark this post and the followings unread

I've built a few of these modules but this one seems to be giving me an interesting problem;

When I run an oscillator into Filter 1 it's sound comes out the High Pass and Notch filters loud and clear but when I switch to Low Pass or Band Pass the volume decreases sharply. Further, the Frequency pot has no effect on the sound no matter which selection I make. The CV inputs don't either. The Resonance and Distortion % pots seem to work fine.

The exact same thing happens on Filter 2.

I've wired this module with the -15V going to the Frequency knob rather than 0V and with the spread coming from both CVSN on Filter 1 and pin 3 of the TL072 (where it meets the 2K2 resistor).

This has worked for me on other CGS49 modules I've built but this is a strange problem that I can't seem to figure out

Does anyone have suggestions as to what I might do to test / fix this problem? Any help would be greatly appreciated.

_________________
Rich
Lower West Side Studio
Fizzbin on SoundCloud
Back to top
View user's profile Send private message
Flareless



Joined: Jan 16, 2016
Posts: 24
Location: Ontario, Canada

PostPosted: Mon Jan 23, 2017 11:14 am    Post subject: Reply with quote  Mark this post and the followings unread

Here is a copy of the wiring diagram I used...

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

_________________
Rich
Lower West Side Studio
Fizzbin on SoundCloud
Back to top
View user's profile Send private message
Flareless



Joined: Jan 16, 2016
Posts: 24
Location: Ontario, Canada

PostPosted: Wed Jan 25, 2017 2:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

This turned out to be due to bad CA3080 chips that I purchased from China.

Thanks for the tip Ken!

_________________
Rich
Lower West Side Studio
Fizzbin on SoundCloud
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 365
Location: germany
Audio files: 9

PostPosted: Thu Jan 26, 2017 7:38 am    Post subject: Reply with quote  Mark this post and the followings unread

Think i have some similar issue... can't recall it exactly right now, but i think it was BP and ??? which were very quiet compared to 2 of the other Outputs...
Good idea to swap the CA3080... but i think i didn't got mine from China/eBay... don't know... i will try it out as the rest seems to be correct from what i remember...

_________________
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 [4 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
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