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 
 Forum index » DIY Hardware and Software » MusicFromOuterSpace.com designs by Ray Wilson
Volts Per Octave Calibrator
Post new topic   Reply to topic Moderators: dnny, Uncle Krunkus, v-un-v
Page 1 of 1 [2 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
elmegil



Joined: Mar 20, 2012
Posts: 1505
Location: Chicago
Audio files: 14

PostPosted: Thu Jan 10, 2013 10:15 pm    Post subject: Volts Per Octave Calibrator Reply with quote  Mark this post and the followings unread

When I built my V/Oct Calibrator, I added an LED from the clock output to ground through a 3.3K resistor. The idea being I wanted to see the pulse of the clock.

Normally, When I'm using it, I'm stepping manually, so I didn't notice until recently that with the LED lit, it was causing my output voltage to droop.

I'm powering this from a good +/- 15V supply, not from a battery. When I measure the current through that branch of the circuit, it's only drawing 2.5mA so I presume it must be a low current LED (was something I bought early on when I didn't know to pay attention, so I don't know definitively).

For now, I've just cut the LED line to ground, but I'm still scratching my head over why it should be behaving this way. Does it have to do with the whole zener + cap power supply arrangement?

This is the circuit: http://www.musicfromouterspace.com/analogsynth_new/VPO_CALIBRATOR/pdf/oscillator_calibrator_schem.pdf

Anyone have any idea?

Thanks....
Back to top
View user's profile Send private message
brock



Joined: May 26, 2011
Posts: 96
Location: Canada

PostPosted: Fri Jan 11, 2013 11:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

The addition of the LED is probably exceeding the current capablility of the zener regulator which is less than 6 mA from a 15V supply. You could reduce R2 to get more current but you will probably find you are introducing a step error on the DAC due to zener current fluctuation causing a voltage variation when the LED is on or off.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: dnny, Uncle Krunkus, v-un-v
Page 1 of 1 [2 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 » MusicFromOuterSpace.com designs by Ray Wilson
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