Unregulated economic power

This power supply is the model I selected for my preamp, because of its good quality / price ratio.
It is not regulated, this means that the voltage available at the output will directly depend on the voltage and your processor.

Here is the schema of power supply:

Here, I chose a remedy 'double bridge'. This means that each transformer secondary is rectified by a diode bridge different. Each bridge consists of four fast diodes BYV-27 decoupled by small ceramic capacitors from 680pF to avoid switching noise of diodes. Filtering is provided by a Pi filter, consisting of a 40V 4700uF capacitor, a resistance of 10 Ohms 1Watt and two 000uF 40V capacitors 10. The capacitor MKP 2.2UF is optional.

For 10 capacitors 000uF be selected models with low series resistance because the frequency response of the power depends directly.
We may substitute an air of self 2mH to this resistance, or better, use a double choke wound on a single ferrite, rising out of phase on the parts + and - power to reject the high frequency interference .

You will need a transformer 2 * 25V (or 24V * 2 depending on what you find) to power the assembly. Output, you must have + / - 35V (2V near a)