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Wallwart with regulators or dedicated power supply?

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TopherTheME:
I'm working on a project right now that uses some very sensitive analog circuits. So to power this project I was thinking of using a dedicated power supply like this: http://www.mouser.com/catalog/specsheets/55225L.pdf

But then I thought that since I don't need anywhere near 25W of power I should just use a wallwart with some regulators, but I'm worried that the wallwart will inject to much noise into the power rails, especially since I will then need a voltage inverter (I need a -10V to -15V) then as well. Which method do you think will generate less noise? I priced out both options and they are priced relatively the same when considering all components and connectors.

Feanor:
I would want to avoid dealing with the mains AC needed to power the dedicated power supply.

Rectifying and regulating the low voltage AC from a "wallwart" (I had to google this we do not call them that in Australia) with out any noise problems should be quite possible. In fact you should be able to beat the specs on the dedicated power supply easily with standard voltage regulator circuits. The voltage ripple in the data sheet is in the 10's to 100'd of millivolts and the supply is a switch mode.

So rectifying and regulating everything yourself would be my choice.

Simon:
you could surround the inbuilt power supply with a shield, having direct access to the transformer will enable you to directly rectify a + and - rail without using inverting power supplies that will also inject noise as you will have to use switching methods

scrat:

--- Quote from: Simon on November 02, 2010, 09:21:55 am ---you could surround the inbuilt power supply with a shield, having direct access to the transformer will enable you to directly rectify a + and - rail without using inverting power supplies that will also inject noise as you will have to use switching methods

--- End quote ---

To obtain the two voltages + and -, the transformer has to be center tapped or you have to use a half-wave rectifier.

Simon:

--- Quote from: scrat on November 02, 2010, 09:50:12 am ---
--- Quote from: Simon on November 02, 2010, 09:21:55 am ---you could surround the inbuilt power supply with a shield, having direct access to the transformer will enable you to directly rectify a + and - rail without using inverting power supplies that will also inject noise as you will have to use switching methods

--- End quote ---

To obtain the two voltages + and -, the transformer has to be center tapped or you have to use a half-wave rectifier.

--- End quote ---

Correct

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