Thanks. With respect to the common ground, even if I use multiple transformers, I'd need to common the ground for rails in the same device.
What I'm looking to achieve is to replace the multiple 5v psu's with individual transformers I run inside my player with a much larger single transformer hence the multiple full wave bridges from a single winding and keep the separation for each supply back to the bridge (common gnds accepted).
I wonder if the multiple transformers is adding anything or if a single higher quality higher va unit will be as good. I'm not looking to reduce the number of rectifiers, smoothers, regs etc.
What I'm looking to achieve is to replace the multiple 5v psu's with individual transformers I run inside my player with a much larger single transformer hence the multiple full wave bridges from a single winding and keep the separation for each supply back to the bridge (common gnds accepted).
I wonder if the multiple transformers is adding anything or if a single higher quality higher va unit will be as good. I'm not looking to reduce the number of rectifiers, smoothers, regs etc.
Most of any problems will be with the grounds. Much easier to have either one big PSU to supply the lot, or lots of genuinely separate PSUs driven from separate secondaries - doesn't have to be separate transformers. 'Separate' PSUs driven from one secondary is about the hardest way to do it. My feeling is that if you knew enough about ground wiring to get it right, you would know enough not to attempt it!
What I have is this
And I'm wondering what will happen if I move the this
I am already dealing with multiple grounds so I've no issue there. Obviously I could got for a transformer with multiple secondary windings and keep that side as per the 1st diagram and the mains side as per the second, but I wonder how using an off the shelf large va transformer would effect things.
I treat each supply as being in its own noise domain but I wonder if going all the way back to the secondary windings is really necessary. I'm not just looking for an it will work or wont, I'm interested in opinions on the quality of the supply.....
I appreciate the comments so far, thanks ;-)
And I'm wondering what will happen if I move the this
I am already dealing with multiple grounds so I've no issue there. Obviously I could got for a transformer with multiple secondary windings and keep that side as per the 1st diagram and the mains side as per the second, but I wonder how using an off the shelf large va transformer would effect things.
I treat each supply as being in its own noise domain but I wonder if going all the way back to the secondary windings is really necessary. I'm not just looking for an it will work or wont, I'm interested in opinions on the quality of the supply.....
I appreciate the comments so far, thanks ;-)
Somehow missed this!!!! Same question applies, how will this effect things compared to individual secondary's?
What I have is this
And I'm wondering what will happen if I move the this
I am already dealing with multiple grounds so I've no issue there. Obviously I could got for a transformer with multiple secondary windings and keep that side as per the 1st diagram and the mains side as per the second, but I wonder how using an off the shelf large va transformer would effect things.
I treat each supply as being in its own noise domain but I wonder if going all the way back to the secondary windings is really necessary. I'm not just looking for an it will work or wont, I'm interested in opinions on the quality of the supply.....
I appreciate the comments so far, thanks ;-)
The first/top picture will work. Each secondary/bridge rectifier/cap is isolated from the others,except for the common ground.
The second/bottom pic will release magic smoke/blow fuses. Simplify it by looking at 2x bridges/caps at a time. If you trace the current flow,you will notice that one part, or the other,of the bridge rectifiers is shorted every cycle. It would work if the grounds were isolated,but they aren't.
Grounding is the problem. You say you are dealing with multiple grounds. At present you have separate routes for charging pulses. In the new arrangement you have not, so you have lost control. With lots of diodes in parallel you have no control over where the currents go. You will be injecting pulses into your ground.
I can't follow either. In my perception, this is what happens:
1.When the transformer top lead is positive, all right-top diodes will be open, while right-bottom ones will all connect transformer bottom lead to ground. In the next half-cycle, the opposite happens. Summing up: all bridges will have the right top/bottom diodes alternatively paralelled/open.
2.When the transformer top lead is positive, all left-bottom diodes will be open, while left-top ones will all connect transformer top lead to their respective cap positive lead. In the next half-cycle, the opposite happens.
3.Between each cap + lead and ground there will be a load (besides the cap itself).
4.The charging current for each cap goes to the same node as right-side diodes anodes, so being distributed among these.
The only issue I can see is right-side diodes get paralelled, making their currents strongly unmatched (due to the different Vf's), possibly causing some to take too much. One could think the common ground would act like a short circuit, but I can hardly see this, since this doesn't connect to other supply nodes, so there's no current path (except for RF, but pointless here).
Did I miss something?
Best regards,
Emerson
1.When the transformer top lead is positive, all right-top diodes will be open, while right-bottom ones will all connect transformer bottom lead to ground. In the next half-cycle, the opposite happens. Summing up: all bridges will have the right top/bottom diodes alternatively paralelled/open.
2.When the transformer top lead is positive, all left-bottom diodes will be open, while left-top ones will all connect transformer top lead to their respective cap positive lead. In the next half-cycle, the opposite happens.
3.Between each cap + lead and ground there will be a load (besides the cap itself).
4.The charging current for each cap goes to the same node as right-side diodes anodes, so being distributed among these.
The only issue I can see is right-side diodes get paralelled, making their currents strongly unmatched (due to the different Vf's), possibly causing some to take too much. One could think the common ground would act like a short circuit, but I can hardly see this, since this doesn't connect to other supply nodes, so there's no current path (except for RF, but pointless here).
Did I miss something?
Best regards,
Emerson
So, why does the ground loop thing happen when using just one secondary, but not when using multiple ones?
I am referring to a situation where eventually all grounds for all supplies get tied together at some point.
I just can't figure out why there will be loops for one single secondary. Just can't find that path for the time being.
Let me propose the following: if we decide then to create a star ground using only one bridge and reservoir, and decide to connect all power supplies there - would then any loops occur? Please suppose that the bridge - reservoir configuration really has a star ground. And everything goes directly there.
I am referring to a situation where eventually all grounds for all supplies get tied together at some point.
I just can't figure out why there will be loops for one single secondary. Just can't find that path for the time being.
Let me propose the following: if we decide then to create a star ground using only one bridge and reservoir, and decide to connect all power supplies there - would then any loops occur? Please suppose that the bridge - reservoir configuration really has a star ground. And everything goes directly there.
I attach a small "block" diagram of what I propose in my previous post (and have also seen it in this forum):
I repeat: one main bridge + reservoir that is star grounded, followed by each power supply that includes its own filtering, regulation and load. And each power supply block connects to the star.
Doesn't each load depend now on its regulator and its previous reservoirs (not the main) to circulate its current?
I repeat: one main bridge + reservoir that is star grounded, followed by each power supply that includes its own filtering, regulation and load. And each power supply block connects to the star.
Doesn't each load depend now on its regulator and its previous reservoirs (not the main) to circulate its current?
Well, think I got it: the above schematic kills local loops.
A loop is still formed following this route: current starts from, say, load A, travels through power cable A, meets reservoir A, then goes to reservoir B, and through power cable B reaches load B which is connected to load A - the loop is closed.
But, when using multiple bridge, there is no direct connection between grounds locally at the secondary. Still, when the "loop" current reaches, say, reservoir A, it will have a path to reach reservoir B through two electrically connected diodes that open 50 times a second.
Is it the problem we talk about?
A loop is still formed following this route: current starts from, say, load A, travels through power cable A, meets reservoir A, then goes to reservoir B, and through power cable B reaches load B which is connected to load A - the loop is closed.
But, when using multiple bridge, there is no direct connection between grounds locally at the secondary. Still, when the "loop" current reaches, say, reservoir A, it will have a path to reach reservoir B through two electrically connected diodes that open 50 times a second.
Is it the problem we talk about?
If I understand you correctly then you have identified the LOOP.
Your diagram shows 3 ground symbols.
These by definition are all connected.
Each supply serves a load. Each of those loads will have a ground connection.
That makes 5 connections to the common ground. Equals loops.
The loops pick up interference. That interference forces the different connections to different AC voltages. It's these different AC voltages that get added to the Signal AC and becomes a contaminated Signal.
Your diagram shows 3 ground symbols.
These by definition are all connected.
Each supply serves a load. Each of those loads will have a ground connection.
That makes 5 connections to the common ground. Equals loops.
The loops pick up interference. That interference forces the different connections to different AC voltages. It's these different AC voltages that get added to the Signal AC and becomes a contaminated Signal.
Yes, this is what I assume. And in the case of one single secondary, this connection is made 100 times per second by means of each conducting diode pair.
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