Isolated and regulted power supply

[spoontex]

Hello,

I'm thinknig about build my psu for my pedals. I want that have isoalted and regulated outputs. This is the shematic. What do you think? they will work?

Thanks!!

[bluescage]

To be on the safe side for the current I would not use a 78L09 regulator, but a 7809 in a TO 220 housing. Some FX boards can draw more current than the 78L09 can handle.

[spoontex]

Okey!! But the DC/DC converter have a max of 160mA. And the PTC? What do you think? if I change the regulator up to 1A, I should increase the ressetable fuse?

thanks!!

http://www.alliedelec.com/m/d/e1cfd3e6faa9515afb7781efbe9d82de.pdf

[spoontex]

The idea is if I want psu with 5 outputs, I repeat the shmeatic fot each output. I think that 160mA per output is enough.

[bluescage]

Sorry I didn't check on the DC/DC converter, but in that case if you are sure that your stompboxes do not draw more than 160 mA you are good with the 78L09. I myself use a 1Spot Power supply and power 10 Stompboxes with a daisychain cable without a problem. I guess your solution will cost more and if you are not using a transformer with separate windings for each DC/DC converter (I think Weber sells one) your outputs will not be isolated.

[m-Kresol]

the "I want to build my own PSU" threads pop up every now and then and I kind of always say the same

I built one myself (starting with mains voltage though) and it's just not worth the effort. Commercial PSUs will have more options, often more than 5 outputs, more power and a smaller footprint for the same amount of money, it's just easy like that. The PSU should be one of the key components of your pedalboard and should not introduce any noise, so it has to be built appropriately too. This is one of the things you're better off just buying, but I get the feeling to want to diy that one too.

[drolo]

I guess your solution will cost more and if you are not using a transformer with separate windings for each DC/DC converter (I think Weber sells one) your outputs will not be isolated.

Actually the DC/DC converter shown in the schematic is isolated, so it basically is the same thing as using a transformer, in terms of isolating the grounds.
I have been using a power supply made of 16 5v-9v DC/DC converters and it has been working great so far. After some tests I actually did not even include any regulation or filtering. The switching frequency on the converters was higher than the audio band and did not seem to create any odd issues with other switching frequencies on the various pedals (charge pumps etc) I might just have been licky with that particular converter ...


One thing to consider if you regulate the power after the converter is that there too you will lose some power.