[sdiy] best ways of portable +/- supply

Ben Barwise clackjunk at gmail.com
Wed Jun 13 00:57:10 CEST 2012


Another option if its not got too many stages is you could convert your idea 
To a single supply design , making vrefs from voltage dividers and using lower voltages , it just gets a little noisy



On 12 Jun 2012, at 21:21, Paul Maddox <yo at vacoloco.net> wrote:

> Dan,
> 
> http://www.robertswarr.com/data/hes14-2003.pdf
> 
> taken from - http://www.robertswarr.com/p/hitron-power-supplies/external-switching-ac-dc
> 
> They can't be the only company making them..
> 
> Paul
> 
> On Tue, Jun 12, 2012 at 6:39 PM, dan snazelle <subjectivity at hotmail.com> wrote:
>> 
>> 
>> 
>> On Jun 12, 2012, at 1:11 PM, Paul Maddox wrote:
>> 
>>> Would be helpful to understand more about your requirements.
>>> That said, you can buy power supplys with dual outputs.
>>> 
>>> I have a couple, takes an IEC C13 input and dives a 6pin DIN output
>>> with +12 and -12 at 1A each.
>>> It's pretty small too.
>>> 
>>> Paul
>>> 
>>> '
>> 
>> 
>> wow
>> 
>> I would LOVE to know more about these dual supply wall warts!!!!
>> 
>> my requirements are pretty flexible==enough power for a handful of opamps, some OTA's, a few LEDS, and some transistors but I can always use low power parts if needed
>> 
>> 
>> 
>> what are the prices like?
>> 
>> 
>> thanks
>> 
>> 
>> Dan
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>>> On Tue, Jun 12, 2012 at 5:05 PM, dan snazelle <subjectivity at hotmail.com> wrote:
>>>> does anyone have opinions on the best way to get plus and minus rails into a portable synth/noisenaker/stompbox type project  WITHOUT using an on board transformer?
>>>> 
>>>> 
>>>> the options I know of are
>>>> 
>>>> 1.AC to DC conversion (ac wallwart plugs in and is converted with regulators and caps to a DC dual supply.  Kind of bulky due to use of large caps.
>>>> 
>>>> 
>>>> 2. Big DC wallwart....a 24 volts wallart would easily get plus and minus 10 volts once regulated. CHEAP and EASY. what are the downsides to this setup?
>>>> 
>>>> 3. DC2DC converters (put in 5 volts get out +/- 15 or +/- 12volts//////) convenient BUT very expensive, bulky, they get very warm and can be destroyed with overvoltage quite easily.
>>>> 
>>>> 4. CHARGE PUMP chips (max1044 etc)    cheap, easy...... VERY PRONE to destruction from over-voltage and static electricity. (though they are used in some pro boxes like the Moog Pedals so there must be ways
>>>> to make them less error prone)
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> Often I am hit with a LIGHTBULB kind of a moment "oh this would be such a great project....so few parts and I could put it in a tiny box!" and then i realize that I will have to provide 2 batteries or a charge pump. Suddenly the small box is a bigger box and the
>>>> amount of parts has grown.
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> I have been messing around with the max1044/LT1045 charge pumps but overall I think they are a bit too delicate for road use....i have had a few MAX1044's die just from having a power supply
>>>> hooked up to them which briefly spiked at a higher voltage than 10 volts
>>>> 
>>>> 
>>>> (my Bench supply, when you turn it on, it seems to jump to a very high voltage for a split second....most chips seem fine with this but not the charge pumps (luckily I figured it  out quickly!)
>>>> 
>>>> 
>>>> Maybe there are ways of protecting these power conversion chips I dont know about. (i usually just put a zener in front of them to keep the incoming power in the proper range)
>>>> 
>>>> 
>>>> ANY thoughts/advice appreciated
>>>> 
>>>> thanks
>>>> 
>>>> 
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>> 
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