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 » Instruments and Equipment » General Discussion
Saw/triangle wave generator schematics?
Post new topic   Reply to topic
Page 1 of 1 [5 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
Dr. K



Joined: Jan 15, 2020
Posts: 27
Location: wisconsin

PostPosted: Sun May 31, 2020 5:57 am    Post subject: Saw/triangle wave generator schematics? Reply with quote  Mark this post and the followings unread

I've been playing around with a "ring mod" (I realize it's not a true ring mod) from a 4093 quad NAND gate. I am using square waves from a 40106. Really simple at the moment.

I was thinking the other day, it would be fun to feed it from some kind of "siren"--I could use the CV input on a 555/556, and feed it triangle or saw tooth wave.

Does anyone have an easy triangle/saw wave schematic? Ideally something you could adjust from a steep leading edge, through a triangle wave, to a steep falling edge? I'm not super familiar with this, but it seems like it should be possible using diodes and a voltage divider in a feedback loop?

Thanks for any info--I've been googling the heck out of it this morning and not coming up with much!
Back to top
View user's profile Send private message
PHOBoS



Joined: Jan 14, 2010
Posts: 5219
Location: Moon Base
Audio files: 683

PostPosted: Sun May 31, 2020 6:38 am    Post subject: Reply with quote  Mark this post and the followings unread

if you want to keep it really simple you should be able to get something like that with 2 diodes a pot and a capacitor
connected to the output of a squarewave oscillator:
- connect the anode of diode 1 to the osc. and the cathode to an outer lug of the pot.
- connect the cathode of diode 2 to the osc. and the anode to the other outer lug of the pot.
- connect the capacitor between the wiper of the pot and GND.
The voltage over the capacitor will be your CV signal.

note that both the amplitude and waveshape will vary depending on the oscillator frequency, but for something like this
it might give interesting results.

_________________
"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
Dr. K



Joined: Jan 15, 2020
Posts: 27
Location: wisconsin

PostPosted: Sun May 31, 2020 11:46 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm going to breadboard that this afternoon. I read up a bit on those systems, and it seems pretty straight forward.

I'm wondering about something else. I recently built a dub sired based on the attached schematic. The first 555 is just a triangle wave generator that feeds the CV of the second. What I'm not sure about is the purpose of the op-amp stage in between.

If the circuit idea you provided works out--and generates an adjustable saw/triangle wave form, would it require a similar op-amp stage? I'm not certain why it is included. Without anything in the feedback loop, it should have 0-gain, shouldn't it? It's a buffer of some kind?


FLU826FJM0V5JR3.LARGE.jpg
 Description:
 Filesize:  49.58 KB
 Viewed:  128 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

FLU826FJM0V5JR3.LARGE.jpg


Back to top
View user's profile Send private message
Grumble



Joined: Nov 23, 2015
Posts: 1237
Location: Netherlands
Audio files: 30

PostPosted: Sun May 31, 2020 11:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
It's a buffer of some kind?

Yes, if you look at the schematic of the internals of the LM555 you will see that pin 5 is a considerable load to a potmeter of 50k and the buffer is there to take off the load from this potmeter.
Maybe you can substitute the LM555 for a cmos ICM7555 of which the data sheet doesn’t say what the value of the resistors are at the control voltage input just that it’s “very high”.

_________________
my synth

Last edited by Grumble on Wed Jun 24, 2020 8:37 am; edited 4 times in total
Back to top
View user's profile Send private message Visit poster's website
Grumble



Joined: Nov 23, 2015
Posts: 1237
Location: Netherlands
Audio files: 30

PostPosted: Sun May 31, 2020 11:53 pm    Post subject: Reply with quote  Mark this post and the followings unread

I’ve found a datasheet from Intersil HERE, where the value is given of the 3 resistors at the control voltage input, being about 100k typical so a total of 33.3k which is better but not high enough to remove the opamp buffer.
_________________
my synth
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic
Page 1 of 1 [5 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Instruments and Equipment » General Discussion
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