AUDIO PC: Direct power to motherboad 24 and 4pin (picoless)

[nige2000]

+12v is needed for the cpu 4 pin and mobo 24pin
or it won't boot
-12V is mostly abandoned these days and not required at least for the recommend boards here

[sima66]

Thanks guys,

So I need only one +12v which is in the slot #10 of the 24 connector and no -12v........right?
There are five 5v, four 3.3v and eight grounds.

The reason for this question is that now I have all the 24 wires tied together.

What I plan to do is to twist all the 5v with, let say, 4 grounds and shield them. Same thing with the all four 3.3v with 3 grounds and the remaining +12v twist with one remaining ground and shield.
This way I will have 3 separate shielded cables.

Any other suggestions?

[Sligolad]

I have run all my boards from Intel, MSI & now GigaByte just off the following connections:



If it is just a dedicated Audio PC then you will not be pulling ant real power through any of the connections on the main ATX connector and the 4 or 8 pin 12v connector for the CPU will be pretty low after you disable Turbo Boost and lower frequencies in Bios.

If I remember correctly from my experiments all the 5v reds are shared, all the 3.3v are shared and all the black grounds are shared so you could wire just one red, one yellow and one black on a dedicated Audio PC.

Grounding is so important I left 3 of them connected and the 5v I left 2 connected, one of these days I will go back to one on each just to confirm there is no sonic difference but for now it works well.

None of the boards I have used in recent years needed the last 4 connections so I cut the 24 pin ATX connector down to a 20 Pin ATX and never looked back.
Cheers, Pearse

[sima66]

I have run all my boards from Intel, MSI & now GigaByte just off the following connections:



If it is just a dedicated Audio PC then you will not be pulling ant real power through any of the connections on the main ATX connector and the 4 or 8 pin 12v connector for the CPU will be pretty low after you disable Turbo Boost and lower frequencies in Bios.

If I remember correctly from my experiments all the 5v reds are shared, all the 3.3v are shared and all the black grounds are shared so you could wire just one red, one yellow and one black on a dedicated Audio PC.

Grounding is so important I left 3 of them connected and the 5v I left 2 connected, one of these days I will go back to one on each just to confirm there is no sonic difference but for now it works well.

None of the boards I have used in recent years needed the last 4 connections so I cut the 24 pin ATX connector down to a 20 Pin ATX and never looked back.
Cheers, Pearse

If I understand correctly doesn't mater which of the 5v slots I choose, as long as I connect one all the rest are connected? Same for the 3.3v, 12v and ground.
Then even Nigel (picture from the first post of this thread) did not have to do all the "branching" on the 24 pin end......just connect in one of the right slots?!

How about the #8 (gray - Power Good), #16 (green - PS On) and #20 (white - NC)? What is the use for those?

[Sligolad]

Your understanding is correct...Nigel's full loading of the plug is safer if you ever intend to use loads of SATA, USB, PCI connections off the Mobo....but I expect you will not be powering anything of any significance off the Mobo...hence the separate PS!!
Regarding the other colour leads the best answer here is to Google "ATX standards" and you will have loads of reading :-)
Best advice if you are not that interested is to avoid them all together unless you have a MoBo from the dark ages that needs them.

[randytsuch]

sima66,

Almost as amazing as the current required by Randy's +12 volts rail. Which with re-reading I think he meant to say 5 volts since he said pin 4. The 5 volts rail is the high current rail these days.

Very interesting ...

No, I meant the 4 pin ATX connector that supplies 12V. My understanding is that this supplies the processor power, which makes sense because it's by the processor.
So how much power you draw depends on the processor used, and what it's doing.
I have a 53W TDP Pentium G3258, so it's not the lowest power processor, but not high power either.

I should also note that I calculated the current by measuring the 115 input to my 12V power supply with a watt meter, and calculated current draw based on that. If I calculate my total power now versus how much power I measured when I had a pico PS, my total power now is higher, 30W before versus 40W now. I don't believe the actual power draw has changed, so my numbers must be a little higher than they should be. If I make a compensation for that, it would be 1.65A instead of 2.2A. Around 20W of processor power, seems reasonable to me.

And for wiring, I connected Power Good and 5V standby (purple) to +5, but I'm not sure if I really needed to. Guess I'll try removing them and see if it makes a difference.


Randy

[Sligolad]

You will need the purple Randy so leave that on the 5v supply.

[sima66]

Your understanding is correct...Nigel's full loading of the plug is safer if you ever intend to use loads of SATA, USB, PCI connections off the Mobo....but I expect you will not be powering anything of any significance off the Mobo...hence the separate PS!!
Regarding the other colour leads the best answer here is to Google "ATX standards" and you will have loads of reading :-)
Best advice if you are not that interested is to avoid them all together unless you have a MoBo from the dark ages that needs them.

Thanks Pearse,

In the beginning my understanding was that you have more of the same voltage&ground wires because of the load between the PS and ATX, but now I see that is because of the leads from the ATX into the MoBo. The actual mobo lead it might not gonna handle if all the power comes from one pin or point.
My MoBo is same Intel as you had in Zuma.

[randytsuch]

You will need the purple Randy so leave that on the 5v supply.

Thanks. I was pretty sure I needed the purple, but I didn't see any mention of it, and have never tried to run without it.

[Sligolad]

Just to be clear Adam I have one 5v Linear supply connected to the Purple lead and two reds in the picture (will work with just purple and one red off this 5v supply)
I have one 3.3v Linear supply connected to the orange lead in the picture.
Finally one 12v Linear supply connected to the yellow lead in the picture.

All the blacks connect together off all the Linear supplies and come together with the three black grounds in the picture (again will work with one black on the ATX connector)

The Intel Mobo is unique compared to the other boards I used with this ATX connector configuration in that it needs a "Special" start sequence.
You need to press and hold in the front panel Zuma start button first while you then switch in the Power Supplies otherwise the board will not start.
You let go of the front Zuma start button when you see the Front Panel light come on, Tony will confirm this.