Linear PSU for NA ATX PC

Jump to Latest
P

Poiram393

Member
Joined 2012
Hi, I have a Home Theater PC that I use to feed my DAC from the USB. To get a better signal, I have a SoTM pci to USB card. For the streaming Imhave etither JRiver or Roon. My question is I know that a PC is a very noisy environnement. Does anyone know a way to at least replace the PSU and put a linear PSU for ATX. In my research, I have found the Teradak system but it’s way over priced. More then $2k just for a power supply. Or am I better go to a NUC pc and add a good linear psu. In this case I won’t be able to use my SoTM USB card…

thanks
 
kodabmx

kodabmx

Member
Joined 2011
It's also contained in a metal box unlike the audio card. Switching frequencies are far above audio range now anyway. If you don't believe me, and since 95% of computers run from a single 12V rail, use a car battery to power the machine and see if it's silent.
 
  • Like
Reactions: 1 users
R

randytsuch

Member
Joined 2003
randytsuch-audio.blogspot.com/2005/10/my-system.html
I did this a long time ago, link
No longer in use, but here it is.
Note that not all MBs will boot up with this kind of DIY PS. I did some research to find one that would, no idea about new MBs.
I also figured out after the fact that my 5V lifepo4 charging circuit had problems, it didn't charge the two batteries at equal voltages. Fixed in other places but not here.

And you really need the lifepo4's or something like it. At startup, there is a large demand for current that the batteries can support. Without batteries, PC will just reboot every time it tries to startup.

Randy
 
  • Like
Reactions: 1 users
JMFahey

JMFahey

Member
Joined 2009
Ok, suppose you build a linear regulated PSU, which is quite doable, of course, but ... what will you do with the CPU, Disks, memory, DAC, scanning keyboard, Mouse signals, etc. themselves?

Anything "Digital" is inherently "noisy" by definition.
 
  • Like
Reactions: 1 users
gadut

gadut

Member
Joined 2008
I also use dell optiplex as my main source for music and movie, use usb to spdif into my diy dac

anyway i have no issue with "noisy" because when i put my ear to the speaker, i can't hear any noise. just confuse with what people claim as "pc is noisy"
 
D

dangus

Member
Joined 2004
Analog on-board audio output from PCs and laptops could be terrible. Without proper filtering or regulation on the power to the analog stages, every mouse movement and hard drive access was audible. The trick was to turn the volume levels to max on the PC then reduce the gain on the powered speakers so the background noises weren't annoying. I presume the designers had no background in audio, and just assumed that volts are volts. Similar design failings exist in some portable devices too; note that Zoom does not provide typical audio specs for their products.
 
J

johan

Member
Joined 2001
A PC motherboard contains VRMs, or buck converters (switch regulators), to convert 12V to 1.4V and 1V (and possibly other voltages?) for the CPU and various other chips. Even if you change the ATX supply, you still have the switch regulators on the motherboard. S/PDIF Toslink output is your best bet and keep the PC in a metal chassis.
 
  • Like
Reactions: 1 users
B

Blitz

Member
Joined 2002
Well,

Having played with all kind of psus in the analog and digital do,aim my experience is...noise adds up.

So, ideally, yes we would have a motherboard with linear regs and some people came up with them...but the less noise you give wven to normal boards...the better...
 
  • Like
Reactions: 1 users
analog_sa

analog_sa

Member
Joined 2002
The only PC i use for a direct usb connection to a dac has been using a linear supply for the last 10 yrs. It is a low power i3, so 5A integrated regs were sufficient for the 3.3v and 5v rails. A more powerful cpu will obviously require pass transistors and perhaps separate transformers for the individual rails but not much deep thinking.

Very surprising this has not been done in many diy designs but i keep forgetting diyers generally scoff at audiophilia
 

Attachments

  • ATX power.png
    ATX power.png
    11.2 KB · Views: 439
  • streacom case open.jpg
    streacom case open.jpg
    417.7 KB · Views: 444
  • Like
Reactions: 1 users
B

Blitz

Member
Joined 2002
I am planning to build my own PSU, thanks for the nice pics...

I mesured the Asus crosshair vii with 5700x...consumption is in total at 35W...

So, i need to figure out a bit what the current distribution is, but i doubt it js more than 2-3A per rail...that js even feasible with some lt3045 boards...and some nice lt4320 upfront...and individual small xformer per rail for isolation of noise...
 
Last edited:
B

Blitz

Member
Joined 2002
Hi Peter,

I read through your old post from 2013...

https://www.diyaudio.com/community/threads/linear-atx-power-supply.241533/page-3

i could not find deep technical docs dor my motherboard (asus crosshair vii)...what I understood so far:

-12V is legacy and maybe not needed andmore.
- a certain power on sequence of the voltages are needed by some biard, while others work fime when all voltages are applied at the same time...

May I ask what will happen if i build only a main switch and applied all voltages at the same time ? Ny risk of breaking something ?
 
You must log in or register to reply here.
Top Bottom