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MEnsing 5th August 2010 02:08 PM

Power supply connections
3 Attachment(s)
For my Aleph-JX I use per channel two transformers (Amplimo 2x18V) and four recifier bridges.

Attachment 182855

First I wanted to parrallel the secondaries as within this picture;

Attachment 182851

But then I saw the following schematic of a pass labs power supply;

Attachment 182854

I haven't seen this way of connecting before and I don't understand it well. Do the phases of the secondaries need to be out of phase with each other or is this possible with just any kind of transformer?

Bill Fuss 5th August 2010 02:26 PM

That is slightly unusual but tying center taps to the neutral cuts the rail voltage in half and I imagine doubles the available current. I'll have to stare at it for a while.

Bill Fuss 5th August 2010 02:47 PM

Instantainious current would stay the same but the duty cycle is cut in half I believe.

BobEllis 5th August 2010 04:30 PM

Is it me or is there a diode drop away from a short when A swings negative relative to 0? Could it be a drawing error?

Bill Fuss 5th August 2010 04:55 PM

I think the center taps are being held at 0 by the interconnection of the trafos. Does that make sense. It's a little hard to get my head around.

BobEllis 5th August 2010 05:14 PM

I see a short from T2 secondary terminal 0 the CT connection between T2 and T3 to the Neutral line, to the negative terminal of BR3, through the lower left diode to T2 terminal A. That's the easiest to see, but the 50% duty cycle short exists for all windings.

Maybe NP will chime in and set us straight.

Bill Fuss 5th August 2010 05:30 PM

Yeah, I could see that after you brought it up. Either we're dummies or the dwg is in error. I'm going to stare at it a while longer.

frags 6th August 2010 12:47 AM

Looks like something wrong with it. R17 is shortened at all.

MEnsing 6th August 2010 05:49 AM

That R17 is shortened is my mistake. I have edited the schematic and removed the part that was not relevant, because I don't want to publish the original schematic here.

Bill Fuss 6th August 2010 10:11 AM

That jumper is an obvious mistake. The problem is in the bridge wiring, it can't work as drawn.

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