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 
 Forum index » DIY Hardware and Software » YuSynth
LED indicator for VC panning?
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
AlanP



Joined: Mar 11, 2014
Posts: 746
Location: New Zealand
Audio files: 41

PostPosted: Sat Apr 23, 2022 9:01 pm    Post subject: LED indicator for VC panning? Reply with quote  Mark this post and the followings unread

https://yusynth.net/Modular/Commun/MIXOUT/mixout-panner-sch.gif

Would a LED going to ground through a resistor, from the output of U101a, be a good location to get a indicator of the amount of panning?
Back to top
View user's profile Send private message
gabbagabi



Joined: Nov 29, 2008
Posts: 651
Location: Berlin by n8
Audio files: 23

PostPosted: Sat Apr 30, 2022 10:01 am    Post subject: Reply with quote  Mark this post and the followings unread

hm, just a guess...

only counting in the offset

the minus 4 Volt going in to 101d coming out as plus 2V
then these
2V and -4V coming out of 101a as 2V, right?

so the LED would be always on with no CV applied,

i guess Smile
Back to top
View user's profile Send private message
PHOBoS



Joined: Jan 14, 2010
Posts: 5591
Location: Moon Base
Audio files: 705

PostPosted: Thu May 05, 2022 12:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

gabbagabi wrote:
hm, just a guess...

only counting in the offset

the minus 4 Volt going in to 101d coming out as plus 2V
then these
2V and -4V coming out of 101a as 2V, right?

so the LED would be always on with no CV applied,

i guess Smile

yes, I think that is indeed correct, with no CV and the pan pot (PAN #1) at the center position.
with a supply voltage of -/+15V and R3 = R4 = 27K the output of 101a can be varied from -1V to +5V
by adjusting the pan pot. This is with T101 set to -4V so once properly calibrated itwill be slightly different.

It would be a good location to get a voltage to drive an LED but it requires some extra components to get it
working properly. Driving an LED so that it corresponds nicely with a varying voltage is a bit tricky.
The best way might be by using PWM but that get's a bit complicated for a single LED. Another way to do it
is with an opamp configured as a current source, or with a transistor. But all methods would need some extra
components and proper testing since it also depends on the used LED and the response you want.

_________________
"My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger
AlanP



Joined: Mar 11, 2014
Posts: 746
Location: New Zealand
Audio files: 41

PostPosted: Fri May 06, 2022 1:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

I think I'm going to have to pull my build of this from my rack, and tack on some flying test wires.

I'm using the subcircuit in another module, and would like some kind of visual indicator Very Happy
Back to top
View user's profile Send private message
gabbagabi



Joined: Nov 29, 2008
Posts: 651
Location: Berlin by n8
Audio files: 23

PostPosted: Sat May 07, 2022 11:33 pm    Post subject: Reply with quote  Mark this post and the followings unread

What comes quickly to my mind,
The difference between 101a and 101d is zero with no CV applied

With CV the difference will rise

Could be antiparallel LEDs + resistor between the two outputs a solution?
Back to top
View user's profile Send private message
PHOBoS



Joined: Jan 14, 2010
Posts: 5591
Location: Moon Base
Audio files: 705

PostPosted: Mon May 09, 2022 11:21 am    Post subject: Reply with quote  Mark this post and the followings unread

gabbagabi wrote:
What comes quickly to my mind,
The difference between 101a and 101d is zero with no CV applied

With CV the difference will rise

Could be antiparallel LEDs + resistor between the two outputs a solution?

good thinking and worth trying. The forward voltage of the LEDs might create a large dark section
and it may affect the outputs of the opamps, it actually creates somewhat of a feedback path for U101a.
But it would be a nice and simple solution.

_________________
"My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [6 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 » YuSynth
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