Linear power supply for pc - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th December 2012, 03:42 PM   #11
d a o is offline d a o  Denmark
diyAudio Member
 
Join Date: Apr 2010
Location: Jutland
Quote:
Originally Posted by qusp View Post
that coreaudio place is a joke, so much ********
okay
I do not know their products
__________________
Greetings Hans
Blog - Music
  Reply With Quote
Old 30th December 2012, 02:21 PM   #12
kp93300 is offline kp93300  Malaysia
diyAudio Member
 
Join Date: Mar 2007
Default 2nd attempt with LT 1084 --success

Hi
I rebuild another module of the power supply for my atom based pc with linux os.
Try it for a few hours and is stable.
Bridge rectifier is the hottest at about 55 C. There is minimal increase in temperature for the 2 LT 1084 .

Those who thinks that power supply for pc audio does not matter should build one to try for themselves.

I will spend the next few days trying to optimize it. I do not have a scope and i seek advice from more experienced diyer. The circuit is from LT 1084 datasheet . The original circuit do not have cap in the output.

I wonder why is there no 120R from V out pin to adjust pins of the top LT 1084.???

cheers

kp93300
Attached Images
File Type: jpg DSC_0151.jpg (336.2 KB, 292 views)
File Type: jpg reg corcuit.jpg (265.0 KB, 281 views)
  Reply With Quote
Old 31st December 2012, 04:43 PM   #13
marce is offline marce  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
Location: Blackburn, Lancs
Quote:
Those who thinks that power supply for pc audio does not matter should build one to try for themselves.
Provide some measurements, it dosn't matter whether you use an SMPS or a Linear, and SMPS's have many advantages, not least being they operate well above audio frequecies.
In fact I would like some views on why people think a linear PSU wouyld be better than an SMPS for a digital based music server, especially a PC where you have numerous gates switching anyway, is it gonna make any difference, not realy. What will make a difference if you are realy worried is isolation qas near the final digital conversion as possible and seperate supplies for the analogue side of the DAC and the following analogue circuitry, optical or wireless from the PC, or SPDIF/I2S galvonicly isolated.
  Reply With Quote
Old 31st December 2012, 05:50 PM   #14
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
Quote:
Originally Posted by d a o View Post
okay
I do not know their products
no worries I just dont like to see them and their voodoo linked on a mostly fairly rational site. add up one of their servers with all the upgrades and you can finish well over 50K, including very fast processors and interfaces etc which puts MORE stress on power supply and ground routing quality and causes MORE noise, for NO benefit for audio playback (despite their miraculous claims), which in truth is quite easily handled by old or low power computers.

its completely needless expense, just so they can be exclusive and add their cut to the many useless, even harmful upgrades. its a joke.

Last edited by qusp; 31st December 2012 at 05:53 PM.
  Reply With Quote
Old 31st December 2012, 06:13 PM   #15
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
the point is, as marce as touched upon above, the audio subsystem should be build in such a way that the PC doesnt matter and that is quite doable, tuning the computer power supply is a pointless endeavour, because when working correctly the computer is still a noise source at bandwidths that even the best linear or shunt supply is powerless to deal with.
  Reply With Quote
Old 31st December 2012, 06:18 PM   #16
diyAudio Member
 
astouffer's Avatar
 
Join Date: Jun 2004
Location: Pittsburgh, crumbling wasteland
You'd be much better off using an optical link from your computer to a DAC with a decent power supply. The motherboard has switching regulators built in to deal with the cpu core and memory voltages. So you're not gaining much.
  Reply With Quote
Old 1st January 2013, 02:07 AM   #17
kp93300 is offline kp93300  Malaysia
diyAudio Member
 
Join Date: Mar 2007
I was skeptical at first but I do hear a difference and the improvement in bass is pretty obvious.
The drop out from the Amanero combo usb to i2s converter is less. The amanero board is powered separately from another linear power supply.

i wonder is the sound difference due to cleaner ground plane.

My apologies, i do not have a scope to use.
this mourning i insert a inductor in the positive rail before the regulator. The pc will not start .
i hope to invite a few friends to do a-b testing between smps and linear ps for pc .

cheers and happy new year.

kp9330
  Reply With Quote
Old 1st January 2013, 03:36 AM   #18
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
what makes you think you have a cleaner ground plane? LDOs, which includes the 1084, generally have pretty crappy transient response and either way what has it got to do with the ground plane? the PC is still covered with little SMPS and the processors are still the same high bandwidth, fast switching, very transient load. all this still dumps into the ground plane, just like before.

Last edited by qusp; 1st January 2013 at 03:42 AM.
  Reply With Quote
Old 1st January 2013, 09:48 AM   #19
marce is offline marce  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
Location: Blackburn, Lancs
Happy New Year
When you do impedance diagrams of PCB power and ground planes using some form of powe3r integrity software, the impedance is not even across the plane at any frequcies and the higher the operating frequency the worse it gets. When any digital system is working especially multi voltage (PC will have at least 5+ on board seperate supplies, DDR memory has 2 or 3), these are bouncing up and down all the time as the gates switch, often having an instantaneous current draw of 100A's. The only way to improve this is during layout, with correct de-coupling, layer stack, local supply location, power islands, shape of power plane islands. When doing a DDR memory interface it uis reccomended to simulate the layout using signal integrity software, this is because these interfaces run at the limit. So with all that going on and adding to the noise spectrum, your front end supply isn't gonna make a lot of difference (unless you have a bad supply and these can be either linear or SMPS). I have worked on systems with both linear and SMPS main supplies and the resulting noise superimposed on an analogue waveform after the DAC is the same (without nit picking with FFT), all high frequency related to system clocks and switching cycles. Isolation was the only cure (planar transformer, capacitive shield, optimised for bandwidth). I would be interested on information on how audible if at all this high frequency noise is, and also does it have any noticable effect further down the line, if it isn't filtered out or isolated.
A further thought is how immune our systems are from EMC interference, the ever increasing use of wireless devices has greatly increased not only the amount but frequency range of RF noise present in our envoironment...
  Reply With Quote
Old 2nd January 2013, 08:55 AM   #20
freax is offline freax  Australia
diyAudio Member
 
freax's Avatar
 
Join Date: Sep 2007
Location: NSW
The only valid reason I can come up with for me wanting to justify it to myself (I've thought about building a linear psu for my pc for ages) is so I can keep computer psu borne noise out of the mains wiring which affects ham radio on shortwave, and at the same time charge a couple of large SLA batteries at 13.5v float.

I then make sure the pc is completely sealed with copper tape and then install aluminium fan filters.

Aside from that also making the computer as rugged and reliable as possible, I believe that Linear power supplies are far more rugged than smps units, feel free to tell me I'm wrong though.

Aside from that does the original poster and a few other posters it seems know about Project 77?

Here is a link: http://sound.westhost.com/project77.htm
__________________
"It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away" - Antoine de Saint Exupéry

Last edited by freax; 2nd January 2013 at 08:58 AM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
linear pc power supply? cowanrg Power Supplies 45 20th July 2012 02:49 PM
Linear Power Supply Kits? jtwrace Power Supplies 0 10th December 2011 03:02 PM
Linear power supply movie_fan PC Based 0 27th September 2011 12:47 AM
Power One 5v 3A linear power supply SilverStrings Swap Meet 0 23rd September 2010 06:06 AM
Power One 12V 10A linear power supply boywonder Swap Meet 0 11th September 2010 03:38 PM


New To Site? Need Help?

All times are GMT. The time now is 08:45 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2