Linear power supply for pc

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you arent reading properly, galvanic isolation is before the synchronous reclocking stage but after fifo buffer, proven to work as designed with measurements the other day at 2ps or less output jitter after the flip-flops/clock buffers. everything before the dual clock board (with dual CCHD975 in my case) is walled off and the i2s reclocked with the new master clock, which is also the ESS clock

I missed this reply. Glad it works. I dont use/like the ESS dac so things are a bit more complicated than that, but I see Ian making progresses :)

Galvanic Isolation protects the DAC fron contamination from the pc usb connection but does nothing about the pollution coming from the mains (spread there by poor SMPTS units). So my solution of (properly) lifting from ground all analog components still stands ground (pun intended).
 
I missed this reply. Glad it works. I dont use/like the ESS dac so things are a bit more complicated than that, but I see Ian making progresses :)

Galvanic Isolation protects the DAC fron contamination from the pc usb connection but does nothing about the pollution coming from the mains (spread there by poor SMPTS units). So my solution of (properly) lifting from ground all analog components still stands ground (pun intended).

The brand of DAC is irrelevant in the case that qusp described, it was only his example.

If the DAC of your preference takes and i2s input then current FIFO works fine, if you want a DAC that needs pcm input then Ian's working on a solution for that too.

I do not believe that a well designed mains derived power supply should suffer conducted noise from that source.
 
Never ever heard of hi-res? Never seen modern ADC specs?
No Idea what Hi res is certainly non of the music I listen to is ever published on it, I have used ADC's to 500 Megasamples per second in designs so fairly modern stuff I doubt there is anything new on the ADC front that I am not aware of, audio does seem to defy the laws of physics so who knows.
 
haha hmm methinks I will need to prioritise, why the hell dont they offer an Ebook version? or do they?

There is an ebook version available through Wiley: Electromagnetic Compatibility Engineering

But ... it is restricted see details here Wiley: Electromagnetic Compatibility Engineering

  • E-books are non-returnable and non-refundable.
  • You'll need Adobe Digital Editions software to read an Adobe DRM e-book, which can be downloaded for free at adobe.com.
  • PLEASE NOTE: Adobe Digital Editions does not currently support read aloud capabilities.
  • E-books must be downloaded within 14 days of purchase.
  • You can download your e-book .acsm file up to four separate times on different computers. The link to do so will be accessible in the My Account section of this web site, or from the confirmation e-mail we send you after your purchase.
  • Once downloaded, an e-book file (Adobe PDF or Adobe e-Pub) can't be simply moved to a different computer. To do so, you will need to use ADE and the Adobe ID that was used to authorize that computer.
  • You can copy/paste up to one full page of text of your e-book, for a total of 15 pages per year.
  • Diagrams, figures, and artwork from the e-book can't be copied and pasted.

So based on that I decided the savings weren't worth it and got the hard copy.
 
One of the biggest if not the biggest polluter of the mains (excluding power line communications, which is deliberatly adding noise!) is actually HVAC and lack of power factor correction.
I like hard copies of books, but for research etc a searchable PDF is great. At one time you could get the IPC c1000 series of specs on CD for not a lot of money, now it is thousands of dollars, whereas paper copies are about a grand. To many people do illegal copies so we have to suffer or pay big money.
 
Marce I assume you mean domestic HVAC, commercial and industrial HVAC usually has power factors ranging from 0.85 for small unit to 0.94 for large units, this is a plain lagging power factor. The exception is the inverter type which has plenty of harmonics, there is a push to reduce the harmonic content of mains powered equipment.
 
The computer I'm using now use to have a bad hiss from the on board audio and the video was fuzzy with less contrast and colours when using the VGA connection to the monitor compared to the DVI connection, I changed the power supply from a cheap 350w no name type brand to a cheap 450w no name type brand because it had a bigger quieter fan. Now the audio is as good if not better as my cd player, there is also now no difference between the VGA and DVI video quality.

So it is possible for a power supply to make a difference, but in my case it was one cheap switch mode power supply vs another cheap switch mode power supply that made the difference
 
I made this linear power supply based on LM 338 with pretracking regulator and the regulated output is 11.8 V. I use a 10 V zener to reg the output.
The trans is 13.5 V ac out and at least 400W capability and is source from an old medical laser printer.
I made it to power an atom based pc which utilize a 60 W smps.

The reg power supply will not power on the pc .

What are the special requirements to use a linear power supply for pc use ??

pointers are most welcomed.

thanks
kp93300

A linear supply for a computer is a difficult project. Even if your computer has no switching supplies on the motherboard (low probability) just the noise from all the digital activity is LOUD. If you have a scope just connect a wire 'pigtail' to the probe and wave is around the mother board. There is all sorts of noise.

Then when you calculate the efficiency and the required headroom for low line Voltage and the waste heat you'll find it borders on insane. And after all that work, will it get quieter than what you have now? The board manufacturer of my PC (Gigabyte) claims 108dB. That's hard to verify but I'm certain it's north of 90. The PSU will also operate at 67 Volts as it did when one of the 3 phases failed in my neighborhood last year. It will also go up to 240Volts with no user input and does power factor correction to 0.98. It's virtually certain your linear supply would not function below 90 Volts and realistically 105 might be the practical lower limit.

I believe there are projects that would give more satisfaction with less work and money.

Here's one for you that could quiet down your analog audio output, REALLY work and is quite simple. I know this works as I used it in my car years ago to add a portable CD and power it from the car - no batteries - that's too easy.

Build a balanced line receiver (Burr-Brown INA134 or Analog Devices SSM2141) and use it to receive analog audio from the PC. Tie the two '-' inputs to the ground from the PC output cable and the '+' inputs to the signal. Any noise on the ground gets subtracted out of the signal. LOTS cheaper and more effective than linear PSUs. Never fight Ohm's law. Use it to your advantage with differential amplifiers.

 
The digital audio equivilent of the Higson particle...
I like the 'Dark Bits' name, it conjours up images of an anti audiophile demon, the Darth Vader of digital audio design, and to quote said gentleman...
"I find your lack of faith disturbing.":p
and as I am in a rather silly mood, another:
"I sense something, a presence I've not felt since.......I swapped my linear supply for a dark SMPS"

I've heard rumors of a new Intel 666 processor / chipset...
 
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Hi All,

I've been tasked with building a linear power supply for a single board computer used as an audio server. It requires 5-9v and 1.5A.

I wanted to build a supply with a cap-inductor-cap followed by a LT1085 or better voltage regulator. I've not see many schematics that use this scheme, so I'm thinking it's not a good idea. Can anyone verify my suspicion?

If it is Ok to use CLC before a voltage regulator, can I use 10kuF+1.0mH+10kuF.

I do have a scope and meters, if that helps in anyway.

Any suggestions would be greatly appreciated.

Thanks,

Vince

PS, I use Pico supplies and fan-less SMPS in my music servers. SeaSonic, I think the name brand is of the larger PC power supply?? Anyway...

Thanks!

V
 
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