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 » Developers' Corner
converting single dc to dual voltage(?)
Post new topic   Reply to topic Moderators: DrJustice
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
overshadow



Joined: Nov 07, 2009
Posts: 2
Location: portland, oregon, usa

PostPosted: Thu May 24, 2012 11:32 am    Post subject: converting single dc to dual voltage(?) Reply with quote  Mark this post and the followings unread

Hello All!!! I may be posting this in the wrong section, and if so, I appologize.

I generally work with single voltage circuits running on 12v or less but I'm building myself a synth/workstation that currently runs on a single +12v dc and I'm now looking to introduce an adsr running on +-12v.
I'm really not trying to redo the entire power system for the entire piece for this one circuit.
I'm searching for a simple solution...so...
My question is; Is it possible to run the main +12v power into two independant 12v voltage regulators (thereby resulting in two independant 12v), sending one to the +12v and one to the -12v of the adsr circuit?
Or is -v actually inherently different (flipped)?
If that's the case, does anyone know of a simple solution to this problem?
many thanks
Back to top
View user's profile Send private message
Mongo1



Joined: Aug 11, 2011
Posts: 411
Location: Raleigh NC

PostPosted: Thu May 24, 2012 1:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

You can't use two regulators as you suggest. That is strongly related to perpetual motion.

There are some chips out there that can do the conversion for you. Depending on your needs though, I'd really suggest converting over to a dual supply system. Doing that would really open up the number of circuits you could use.

Gary
Back to top
View user's profile Send private message Send e-mail
overshadow



Joined: Nov 07, 2009
Posts: 2
Location: portland, oregon, usa

PostPosted: Thu May 24, 2012 5:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hey Mongo,
thanks for the reply.
looks like I'll need to upgrade to a dual supply.
Out of curiosity though, would it be possible to run a +-12v circuit off two independant power supplies (one for the -12v and one for the +12v)?
Back to top
View user's profile Send private message
Mongo1



Joined: Aug 11, 2011
Posts: 411
Location: Raleigh NC

PostPosted: Thu May 24, 2012 6:58 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
would it be possible to run a +-12v circuit off two independant power supplies (one for the -12v and one for the +12v)?


Yes - that's pretty easy. You would connect the positive side of one supply to the negative side of the other. That would be your system ground.

Gary
Back to top
View user's profile Send private message Send e-mail
elmegil



Joined: Mar 20, 2012
Posts: 2177
Location: Chicago
Audio files: 16

PostPosted: Thu May 24, 2012 7:02 pm    Post subject: Reply with quote  Mark this post and the followings unread

Be wary that you'll want the two to switch on/off at the same time. I recall something about it being a bad idea to have two wall warts hooked up such that one was on and the other off, for example.
Back to top
View user's profile Send private message
richardc64



Joined: Jun 01, 2006
Posts: 679
Location: NYC
Audio files: 26

PostPosted: Fri May 25, 2012 6:32 am    Post subject: Re: converting single dc to dual voltage(?) Reply with quote  Mark this post and the followings unread

overshadow wrote:
If that's the case, does anyone know of a simple solution to this problem?

I love how that one word always seems to fall by the wayside in these threads. It's like it causes a blind spot.

Although a dual supply would allow more types of circuits to be used, if you really don't want to "... redo the entire power system for.. this one circuit" it might be possible to adapt that particular ADSR to single supply, since envelope generators in general take in a unipolar signal (the gate and/or trigger,) and put out a single-ended voltage -- the envelope.

Let's see it.

_________________
Revenge is a dish best served with a fork... to the eye
Back to top
View user's profile Send private message Visit poster's website
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Fri May 25, 2012 7:45 am    Post subject: Reply with quote  Mark this post and the followings unread

You can buy (although they are quite expensive) DC to DC converters. These days they come on one big black chip, say,.. matchbox sized. You put one DC voltage in, and get another out. Up, Down, and I'm sure Scott Stites told me about one which took in say 12DC unipolar, and converted it to +/-15V with a centre ground.
Keep in mind that they can't supply anymore wattage than what you put in, in effect, even less with efficiency. So If you had 12VDC unipolar in @1A, you wouldn't get +/-15V at anymore than 300-400mA.
Apart from that, I'd say, just bite the bullet and invest in a good quality linear PSU +/-15VDC @1A
It will pay for itself in frustration very quickly if you plan to do much more Synth DIY.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
analog_backlash



Joined: Sep 04, 2012
Posts: 393
Location: Aldershot, UK
Audio files: 21

PostPosted: Thu Nov 01, 2012 5:40 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi,

I've not tried it myself, but I've seen circuits in the past where a very simple DC-DC converter is made from an oscillator (often CMOS) and a couple of capacitors and diodes. This generates a negative voltage which can be used to supply the the -V pins of op-amps. There is an example shown here:

http://www.extremecircuits.net/2010/06/negative-auxiliary-voltage.html

The current supplied is small, but if it's just to power a few low-current op-amps, it might just work. It's worth a go as nothing much is likely to go wrong.

However, it's still a better option in the long run to build a dual-rail supply. The one I'm using now was built by my cousin for me when I first started getting into electronics. It must be 30 years+ old now!

Just a thought,

Gary
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: DrJustice
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 » Developers' Corner
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