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LinPack 10th August 2006 07:04 AM

What's wrong with this PSU schematic
2 Attachment(s)
Hi mates

My friend design this power supply for my first amp because i dont have much knowledge in audio field.

But when i asked him further about this schema, he could't tell me something, as follow:

1.Why using common 0V DC? Is there any advantage over seperate GRND power supply found on (which have +VDC; +GRND; -VDC; -GRND)

2. Is that big cap 10.000uF between +VDC and -VDC needed?

3. How about adding 8 small bypass caps for 2 bridge? I found some Sony design have that caps

Please explain me more. I'm very confused. It took me a week, digging the internet and still could answer my question.


I dont mind using more components, but i only have average-low quality parts (they dont sell hi quality). So i need a design that quite stable with crappy stuff :D, avoid the regulated PSU

AndrewT 10th August 2006 07:13 AM

correct the mistake on your schematic.
You have +35 and +35V at present.

The lower bridge is back to front. Swap the direction of the diodes and the + & - signs.

The bridge can benefit from small caps in parallel to each diode, but this can give rise to ringing which sounds worse than the problem the caps are intended to cure.

Instead if you go down the route of snubbing the diodes then use an RC snubber with a series resistor and capacitors in parallel to each diode.
search for RC snubbers

Move the last electrolytic to the other side of the RC snubber at the output.

Move the 0V to the "T" between the rectifiers. Run a wire from this "T" to a separate audio ground.

LinPack 13th August 2006 07:19 PM

Thanks so much for your response, AndrewT

I'm looking at that site now and a thread about Carlos' snubberized power supply. i didnt see that thread before i asked, sorry!

All these analog stuffs are really pains in the **s. I prefer digital signal. Hope that i could comprehen Carlos' design and dont have to ask my friend about it anymore.


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