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-   -   Correct way for PSU? (http://www.diyaudio.com/forums/solid-state/232495-correct-way-psu.html)

Walkalone 21st March 2013 06:52 AM

Correct way for PSU?
 
What's the correct way to tracks on power supply PCB with full 8 diodes regulator?!

1. Common tracks for GND of 2 haft wave. Star ground is this track, not the point (the entire length of the track). It's will connect pins (+), (-) of caps and are the GND of circuits.
This is usual way. With < 8 total caps, it's good. Reference power supply sells at DIYAUDIO Store use it. But with the very many caps, the length of track is the problem. The track's resistance make bad effects.

2. Separately tracks and connect all at the star ground.

3. Use ''T-Ground''. Ex: On positive rail, separately track for cap banks by 1 track. GND for cuicuits by 1 separately track. It's common GND. All track connect at star point. Similar with negative rail.

So, (2) same way with (3).

What's the best way? I think (3). Anybody can suggest me.

Walkalone 22nd March 2013 06:42 AM

Oh, come on. Nobody can't help me?

I think (3) is excellent ways. What do you think?

Please give me your opinion!

CBS240 22nd March 2013 09:02 AM

You description is vauge. Can you draw out what you mean? Typically after the rectifier you have a set of filter caps to which each gnd return goes to the centertap. Then you may have a small resistor to a capacitor bank that powers the amplifier. The gnd returns for these are seperate paths to the centertap forming the star gnd point. The concept is to seperate the charging pulses from the power transformer from the high current pulses returning from the speaker.

Walkalone 23rd March 2013 04:58 AM

2 Attachment(s)
Ok, i'm attack the files.

In left, it's usual/popular and simply in layout. If you have total <8 caps, the star ground is the length of common track, its sort. The track resistance is not significant. Circuit's good.

Right, i think call it by ''T-ground''. Separate track connect caps bank and return at star point. Both pos. & neg. so. GND return from circuits, Speakers are connect at star point too.

I'm worry because if you use too many caps, the track length would be too large, the resistance is too high. (1) way is simply in layout more than (2), (3).
My plan is use total 20 caps in main supply.

If you are, you will choose?

DF96 23rd March 2013 11:50 AM

The left-hand circuit is not too bad, apart from the labelling. The ground bus in the PSU should not be labelled 'main star ground'; it isn't a star and it isn't main.

The right-hand one will have serious buzz problems.

The proper way to do it is to use a ground bus in the PSU, as in your left-hand circuit, but do not make even the clean end of the PSU the signal star ground. Instead, have a separate star ground which the PSU ground also connects to. This is spelled out in lot of places, so I cant imagine why people still keep getting it wrong.

Walkalone 23rd March 2013 01:48 PM

Quote:

Originally Posted by DF96 (Post 3423720)
The left-hand circuit is not too bad, apart from the labelling. The ground bus in the PSU should not be labelled 'main star ground'; it isn't a star and it isn't main.

The right-hand one will have serious buzz problems.

The proper way to do it is to use a ground bus in the PSU, as in your left-hand circuit, but do not make even the clean end of the PSU the signal star ground. Instead, have a separate star ground which the PSU ground also connects to. This is spelled out in lot of places, so I cant imagine why people still keep getting it wrong.

I don't understand exactly what you want say to me. If you can, please use a pic to describe it.

jaycee 23rd March 2013 05:21 PM

Imagine your right hand picture, but do not make the star point between the rectifiers. The star point should be at the capacitors.

DF96 23rd March 2013 05:24 PM

No, the star point should be to the right of the capacitors. The cap themselves should be on a bus, like the left-hand circuit.

jaycee 23rd March 2013 05:29 PM

1 Attachment(s)
Yeah, that is what I meant :) This is the power supply board I have used for a gainclone, no hum problems. The bridge rectifier and transformer centre tap connect on the left. The star ground point is just left of the fuses, between the capacitors.

PMI 23rd March 2013 06:02 PM

@Walkalone: I think what they are telling you is to keep the common point of the rectifiers, away from the place where the speaker return (speaker ground), and other signal grounds are connected together. "star" ground is just a word, a label that people can disagree on...

So, imagine a long circuit board, with rectifiers, or rectifier connections at one end. Then, a double row of electrolytic capacitors, like the layout above. 2-4-8... As many as it takes for your project. Perhaps some small resistors to help filter the AC ripple. At the opposite end of the circuit board, a connection or connections for signal grounds, speaker returns, control circuits etc. In between, a medium trace which connects the common point of the two rectifiers, to the common point of all the other ground connections.

It might also help to post the intended use of the power supply, you could get better advice if you do.


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