[sdiy] best ways of portable +/- supply

[dan snazelle]

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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