Split-rail DC from DC laptop power supply?

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rif

rif

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Joined 2003
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Check out the Hagerman (haglabs) circuit for the bugle 2 and the piccolo (first one not the 2). IIRC, parts of each circuit accomplish what you need using filtering, rail splitter and 7662. Member 6L6 analized the results and liked what he saw.
 
A

AndrewT

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Joined 2004
18Vdc will allow +-9Vdc when split.
If you need to regulate that or add filtering to reduce the SMPS noise then you will get less than 9Vdc

Assuming an LDO regulator dropping 1V then the typical split rail output from 18Vdc would be around +-8Vdc.
For a normal series regulator expect a voltage drop of around 2 to 3V giving a split supply of +-6Vdc to +-7Vdc.
 
sofaspud

sofaspud

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Joined 2005
That won't make a bipolar supply.
You could gain a bit of voltage by filtering & regulating the 18V, then splitting it.
Personally, I would then just use a pair of series resistors. (Don't knock it unless you include DBT listening results.) Suboptimal is explicit in the thread title.
 
JMFahey

JMFahey

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Joined 2009
tabarddn said:
Hi, thaks for that Andrew, I now understand.
But these will be 1 x 18 VDC power supply feeding 2 seperate Ultra-low Noise Adjustable Voltage Regulator. So each one will see 18 volts., they will not be splitting 18 volts as is the normal circuit.:confused::D
Click to expand...
Even if you use 2 regulators, they are in parallel, not in series, no matter how you connect them the *maximum* voltage difference between any two points in the circuit fed by that single 18V supply is ..... 18V ... period.
While +/-15V implies , just by itself, a 30V (15+15) difference between its ends.

Actually even more, because you lose some when regulating.
 
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