electro-music.org   Dedicated to experimental electro-acoustic
and electronic music 		 
 Front Page  |  Radio  |  Forum  |  Media  |  Playlists  |  Wiki
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 

 Forum index » DIY Hardware and Software » Thomas Henry designs
OTA info download. CA3080, LM13700 etc..
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [8 Posts]		 View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
adambee7



Joined: Apr 04, 2009
Posts: 420
Location: united kingdom
PostPosted: Sat Jan 29, 2011 8:16 am    Post subject: OTA info download. CA3080, LM13700 etc.. Reply with quote  Mark this post and the followings unread
Found this great article on OTAs. A bit of extra info when building TH's stuff. Very Happy Very Happy
http://www.idea2ic.com/LM13600/UsingOTAs2.pdf
Back to top
View user's profile Send private message
JRock



Joined: Mar 05, 2010
Posts: 87
Location: Bucks County, PA
Audio files: 1
PostPosted: Sat Feb 12, 2011 6:09 am    Post subject: Reply with quote  Mark this post and the followings unread
Thanks for the infos!
Very helpful
Back to top
View user's profile Send private message
inlifeindeath



Joined: Apr 02, 2010
Posts: 316
Location: Albuquerque, NM
PostPosted: Sat Feb 12, 2011 7:52 am    Post subject: Reply with quote  Mark this post and the followings unread
great article! I recently built this VCO from the article and the pitch is really unstable. Is there a way to better stabilize the frequency of the osc? I did include .1 and 10 uf caps on the power rails.

untitled.bmp
 Description:

Download (listen)
 Filename:  untitled.bmp
 Filesize:  457.34 KB
 Downloaded:  570 Time(s)
Back to top
View user's profile Send private message Visit poster's website
wmonk



Joined: Sep 15, 2008
Posts: 530
Location: Enschede, the Netherlands
Audio files: 15
PostPosted: Sat Feb 12, 2011 8:51 am    Post subject: Reply with quote  Mark this post and the followings unread
inlifeindeath wrote:
great article! I recently built this VCO from the article and the pitch is really unstable. Is there a way to better stabilize the frequency of the osc? I did include .1 and 10 uf caps on the power rails.

What type of capacitor did you use for C? Using a polyester or silver-mica here will give a more stable frequency then a X7R ceramic.
_________________
Weblog!
Back to top
View user's profile Send private message
inlifeindeath



Joined: Apr 02, 2010
Posts: 316
Location: Albuquerque, NM
PostPosted: Sun Feb 13, 2011 11:33 am    Post subject: Reply with quote  Mark this post and the followings unread
ah ha, i did use a ceramic cap.
Back to top
View user's profile Send private message Visit poster's website
wmonk



Joined: Sep 15, 2008
Posts: 530
Location: Enschede, the Netherlands
Audio files: 15
PostPosted: Sun Feb 13, 2011 11:57 am    Post subject: Reply with quote  Mark this post and the followings unread
inlifeindeath wrote:
ah ha, i did use a ceramic cap.

It depends on the type of ceramic too. C0G ceramics have a real low leakage, like polystyrene. That makes them excellent for timing capacitors. When you buy ceramics, normally they aren't C0G, unless noted. In general, use the best capacitors available for the timing caps, and other caps in the audio path. For real low value (like 10pF), it doesn't matter much, and decoupling capacitors can be low grade too. I use multilayer ceramics for those.
_________________
Weblog!
Back to top
View user's profile Send private message
inlifeindeath



Joined: Apr 02, 2010
Posts: 316
Location: Albuquerque, NM
PostPosted: Sun Feb 13, 2011 12:04 pm    Post subject: Reply with quote  Mark this post and the followings unread
awesome, thanks for the wisdom.
Back to top
View user's profile Send private message Visit poster's website
Usedtobe



Joined: Sep 10, 2009
Posts: 8
Location: Austin, Texas
Audio files: 2
PostPosted: Tue Apr 05, 2011 9:06 am    Post subject: ota vco frequency math Reply with quote  Mark this post and the followings unread
howdy! I'm analyzing the same vco on paper. the equation they give for frequency is (Ic/4c * RA * Ia) . It also says that one microamp (0.000001 amps) yields a 200hz frequency, but when I go through it all I get a value of 427.54. Checked my math, did it again, still 427.54. What's going on here?

thanks!!
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 [8 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 » Thomas Henry designs
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

Log in
Username:     Password:      Log me on automatically each visit    


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2026 by electro-music.org