+15-15 from 9v

[dubiousss]

So I see solutions for +9/0/-9 or +18 and also transformer +15-15 but I haven't seen any +15 -15 from 9v. I run all my pedals of a 12v daisy chain and putting a transformer anywhere near my wiring will kill me. I did have a solution for a little bit. I ran 12v to 7809 to 7066 for 18v then to a second 7660 for reverse polarity but the current sagged so i got +14 -13 and with regulators +12 -12, so with my +14-13+12-12 I was able to get my maestro ring mod working. I could hear the wine in it though and something was getting very hot, so I breadboarded it again but this time everything got hot and now ive fried 3 7660's :\ Surely we can come up with something that give a stable +15-15+12-12 for a 9-12V source?

[newfish]

Having never built any sort of power supply, this is where I'd start...

Assuming you've got 12v DC coming in (?), could you use a charge pump to give you 18 (or maybe 20 or so) v DC, then regulate down to 15v

...next would be getting your + / - supply sorted out - but a charge pump wouldn't need a transformer.

Just a hunch.

[Ripthorn]

I posted a schematic/diagram for this several months ago.  You simply use a 1044 or similar chip and wire it for both the negative voltage and doubled voltage parts of the circuit.  Here it is http://www.diystompboxes.com/smfforum/index.php?topic=77600.0.  Is this what you are looking for?

[Cliff Schecht]

You could design a switcher with taps for any voltage you want (including +/-9, +/-12 and +/-15V). Perhaps I can design you one for this months competition . All I need is requested input voltage range (i.e. what voltage you like for the input) and voltage/current requirements for each rail. I wouldn't expect you to be able to build it though as it would be a fairly costly endeavor (getting boards made + parts + required custom magnetics).

I already have a +/-15V switcher designed for PAiA that works from 9V but it's probably not going to be released for a while longer. It would suit your needs well and can handle over 30W without any fuss.

[dubiousss]

ripthorn im glad you posted that as i was about to start playing round with this transformer i ripped out of a wallwart (no insulation), will try with last 7660

[dubiousss]

Hmm, those 555 circuits give me +15 -15 but as soon as I plug that into a circuit it drops :\

[StephenGiles]

You are far better off
1) buying a good quality transformer which is able to stand a current draw well in excess of your requirements - 1 amp is good.
2) Step the voltage down to say dual 18v, with options for dual 15v, dual 12v and dual 9v for starters - then single rail supplies are also there for stompboxes
3) using a well designed PCB

say's he who's power supply was built on veroboard

and I almost forgot - only use decent quality components in the power supply!

My goodness you would even be able to power your train set with that - I wish I still had mine - 60007 A4 Pacific Sir Nigel Gresley, the original loco is still running for steam specials in the UK!

[Krefu]

I'm sure you guys know way better methods than me for this but I made 4 channel mixer, powered with +-15V from 9V using a TEL 15-1223 from Traco Power.
It works great.

[Strategy]

I built my Maestro Ring Mod power supply on perf and used a transformer. I'll try to post the schematic I used here, it's on my other computer- it puts out +/- 12V and +/-15V which you need both for the Ring Mod project. I bought a transformer that's too big, required me to have a huge container, but using hammondmfg.com to see the full lineup of sizes will be useful to you.

It was pretty easy to perf the weird thing was making sure I could think 'backwards' to get the solder side correct. Took a couple of tries.

Will try to post it this weekend
- Strategy

[rustypinto]

I posted a schematic/diagram for this several months ago.  You simply use a 1044 or similar chip and wire it for both the negative voltage and doubled voltage parts of the circuit.  Here it is http://www.diystompboxes.com/smfforum/index.php?topic=77600.0.  Is this what you are looking for?

I built this circuit. You really have to know what kind of current you want out of it since there are a lot of losses with the diodes and capacitors. Here are some of my numbers using an Intersil TC7660 and resistive loads:

Silicon diodes:
"+17V" = ~15.6VDC@10.4mA
"-17V" = ~-12.5VDC@10.4mA

Schottkey diodes:
"+17V" = ~16.5VDC@11mA
"-17V" = ~-13.5VDC@11mA

All caps were 1uF electrolytics except the caps at each generated supply, which were 47uF to filter more of the ripple.

In general, this is a great supply to run a quad of low power op-amps (eg. TL08X, TL07X, etc).

[xshredx]

http://www.cui.com/pdffiles/VASD1-DIP%20Series.pdf
http://parts.digikey.com/1/parts/731746-converter-dc-dc-15v-out-1w-vasd1-s5-d15-dip.html

[dubiousss]

Is there any way I could add two 15+'s for more current? Like running two 7600's in parallel. That +15-15 chip only give out max 33mA and the 1495 alone takes 12mA after regulation..