Suggest a board - 18vac to 12vdc

[Mitch311]

Hey Everyone,

I am building a CDA-254L kit from class D audio and have a spare 18vac output on the transformer that I wish to utilize to run a miniDSP and maybe a 12v case fan. So I need a board (very much preferably premade) that supplies nice clean power as my miniDSP will be my DAC.

Any suggestions? I have seen stuff on eBay but I have no idea of quality or what to even look for.

Thanks!
Mitch

[luka]

well premade... look at DC-DC bricks or non brick version... just don't know how clean it will be, but you can always add some ultra low noise regulator after DC-DC

[Mitch311]

I just need something that takes 18vac and turns it into 12vdc. If i have to make it myself i can try, but there is a lot of boards on eBay that do this supposbly, I just dont know how to decide wether they would be decent or not.

See for example: Class D Audio Heavy Duty DC Power Supply - Power Supplies - PRODUCTS but would also limit the voltage out to 12 vdc

Thanks for your reply btw

[nigelwright7557]

I would just use a bridge rectifier, a dropper resistor and some smoothing.
You can work out the resistor value and wattage from the fans max dc current.

[AndrewT]

I would add on regulation.
Use an lm7815 or lm317 set to 12Vdc

the kit you need:
mains fuse holder
switch
transformer
bridge rectifier
smoothing capacitors
regulator
decoupling capacitors
solid core wiring in a variety of coloured insulation.
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