negative voltage?

[biggs1249]

So I am building a MFOS noise generator. I just finished the populating the board. It has a place on the board for +12v and -12v. I assumed you would only use one of those. But I saw a picture of an assembled one of the MFOS website and both contacts had wires. So how do I wire this? there is +12, ground and -12. Thanks for your help in advance.

[Wounded Paw]

You need a dual power supply which would supply all three. Not too hard to make if you're already building. I don't have a schematic handy but you should be able to find one online somewhere.
Or possibly buy one already made.

[biggs1249]

Ok. here is what I am building. http://www.musicfromouterspace.com/a...CORNUCOPIA.php

I bought a 12v DC wallwart. I guess that wont work. I now realize that i cant find if it specifies AC of DC. can a dual power supply be DC? elsewhere on the page he specifies AC power. does that mean this is DC?

also are there any commercially available dual power supplies that fit my needs? (I need a higher current then whats on the sheet because I am putting two modules in one enclosure). I might be able to build one but I'd like to make sure this project is a success before I go and do something else.

I have a bench power supply. It has variable 18v + and -. Its an HP 6235A power supply. It doesn't say if its AC or DC. can I use that to test it?

sorry for so many questions. still learning.

[anechoic]

Originally Posted by biggs1249

Ok. here is what I am building. http://www.musicfromouterspace.com/a...CORNUCOPIA.php

I bought a 12v DC wallwart. I guess that wont work. I now realize that i cant find if it specifies AC of DC. can a dual power supply be DC? elsewhere on the page he specifies AC power. does that mean this is DC?

Judging by the schematic, that circuit would not take an AC input; the op amps need DC. I don't see any rectification or regulation on there - the diodes are part of the audio path

also are there any commercially available dual power supplies that fit my needs? (I need a higher current then whats on the sheet because I am putting two modules in one enclosure). I might be able to build one but I'd like to make sure this project is a success before I go and do something else.

Here's one that would work:

http://search.digikey.com/scripts/Dk...me=271-2277-ND

Note that you would have to supply an enclosure and AC cord for this one. You can get switching power supplies that are smaller and less expensive, however on some of the crappier ones out there, you can get switching noise in the output. Although given that this is a noise generator circuit, that may be a non-issue.

You can also make a bipolar supply from two wall warts, as long as the outputs are floating (they nearly always are). You would tie the negative side of one supply to the positive side of the other - this point becomes the common (grounded) terminal, and the remaining pair of wires are +12V and -12V.

I'd also take a look on ebay, as this sort of thing can turn up cheap as industrial surplus. All Electronics is another good place to look (though they don't appear to have anything suitable at the moment), as is Burden's Surplus Center.

I have a bench power supply. It has variable 18v + and -. Its an HP 6235A power supply. It doesn't say if its AC or DC. can I use that to test it?

That's a DC supply. An 18 VAC benchtop supply would be nearly useless to most people. It must be pretty old, as Agilent doesn't seem to have the manuals on their website.

[Kooldac]

I def agree this thing looks like it was meant to get a very special power supply. Pretty stupid of the creator to not make a note of this in the details. If you are feeling really DIY or want to go searching on the internet, you could create another board with a charge pump IC to get you the 12 volt rail to rail swing where you would normally get +12 to neutral.

[biggs1249]

Originally Posted by anechoic

That's a DC supply. An 18 VAC benchtop supply would be nearly useless to most people. It must be pretty old, as Agilent doesn't seem to have the manuals on their website.

so that means that will work right?

[anechoic]

Originally Posted by biggs1249

so that means that will work right?

Yup, should work just fine.

[MAMMOTHvolume]

you could use one of these http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1017

[biggs1249]

what about this? http://www.musicfromouterspace.com/a...WARTSUPPLY.php

[biggs1249]

Originally Posted by MAMMOTHvolume

you could use one of these http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1017

doesn't that say 10v max? I need 12

[OxJohnson]

Would one of these work: Powdec PTE43-31.

There is a link to the spec here: http://www.powdec.com.tw/pages/pte43.htm

V1: +5V @ 6A
V2: +12V @ 3.6A
V3: -12V @ 0.5A

I have a few floating around somewhere...

Ox.

[biggs1249]

where can I find jacks which support dual power?