Hey guys,
This needs a bit of explaining and there's a few questions. I'll lay it all out and then give a final #'d recap of what I need help with.
So,
I currently use a 550w FANLESS Seasonic ATX PSU for an audio only PC that I've got. It's fine, but I'd like to have a go at making my own linear PSU to feed all the rails of the PC.
I know there may not be much proof on the topic, but hopefully a linear PSU makes a difference to the sound. I'm going to try, so keep that in mind.
Info on my PC:
*The audio PC is just a transport outputting the music data via USB to my stand alone DAC. There's no soundcard or Digital to Analog conversion going on inside the PC.
Parts:
standard mATX Gigabyte G1 Sniper M5 motherboard,
i5 4670k CPU (underclocked to 1.6Ghz),
16GB (4x 4Gb 2100mHz underclocked to 800mHz),
1 Corsair 128Gb SSD,
and 2 PCIe cards (1 is a USB 3.0 card that needs to be able to supply up to 3A to it's peripherals, and then 1 expansion card that takes almost no power).
So no big power eaters, and I'd say total we're looking at ~60-90w. I haven't tested this myself though, just guessing from the components.
The few full ATX linear PSUs that are out there cost at a minimum $1700USD from TeraDaks and go up to $3000/5000 for a Paul Hynes one. Both too far gone on my personal cost to benefit ratio.
I'm not 100% sure of what rails the PC needs since this is my first kick at the can, but from what I've found I'll need to supply +12v, -12v, +5v, -5v, +3.3v, and a special +1.65v for a dedicated RAM PSU.
Is that correct?
As for current, though the PC isn't going to be using much power, I'd like to have a good supply on hand just in case I reuse it for something else in the future. So I'm looking at something like the Seasonic's 500-600w.
As for how, I was thinking to use AMB's Sigma 11 Linear PSU boards + toroidals for the single rails, and the Sigma 22 for the +/- rails. These PSUs are proven work horses and have super low ripple. This part of the build should be pretty straight forward, selecting voltages and then spec'ing the boards+toroidals to output it. However, how many toroidals and what size (voltage and physical) will I need to supply those boards?
One other problem I have is with getting the PC to start. From what I've read the ATX PSUs don't just simply go from either "off" to "on". There is a sequence that the rails need to go live in, and since I've got a dual-bios motherboard, one of the 5v lines actually goes off and on twice.
- So, what I need to make or scavenge is some kind of switch that will start up my DIY PSU in the same order so that the result is just 'push button' :-D
Recap:
1. What are the necessary rails that an ATX PSU needs to supply?
- and keep in mind that I need a dedicated 1.65v rail to supply the RAM.
2. How many toroidals, and of what size (voltage and physical), will I need to supply power to the various rails?
3. Where can I find, design, or make a switch/logic board to correctly supply the timing sequence of the rails during power on/off?
- I want to just connect the looms (24pin, 8pin, 4pin) and then use my DIY PSU with my audio PC as if it were a standard ATX one. Some quirks, sure, but nothing about opening the lid or pulling cables.
Thanks a lot, guys. That's it for the first volley, and I'm sure I'll have more as the project moves ahead.
This needs a bit of explaining and there's a few questions. I'll lay it all out and then give a final #'d recap of what I need help with.
So,
I currently use a 550w FANLESS Seasonic ATX PSU for an audio only PC that I've got. It's fine, but I'd like to have a go at making my own linear PSU to feed all the rails of the PC.
I know there may not be much proof on the topic, but hopefully a linear PSU makes a difference to the sound. I'm going to try, so keep that in mind.
Info on my PC:
*The audio PC is just a transport outputting the music data via USB to my stand alone DAC. There's no soundcard or Digital to Analog conversion going on inside the PC.
Parts:
standard mATX Gigabyte G1 Sniper M5 motherboard,
i5 4670k CPU (underclocked to 1.6Ghz),
16GB (4x 4Gb 2100mHz underclocked to 800mHz),
1 Corsair 128Gb SSD,
and 2 PCIe cards (1 is a USB 3.0 card that needs to be able to supply up to 3A to it's peripherals, and then 1 expansion card that takes almost no power).
So no big power eaters, and I'd say total we're looking at ~60-90w. I haven't tested this myself though, just guessing from the components.
The few full ATX linear PSUs that are out there cost at a minimum $1700USD from TeraDaks and go up to $3000/5000 for a Paul Hynes one. Both too far gone on my personal cost to benefit ratio.
I'm not 100% sure of what rails the PC needs since this is my first kick at the can, but from what I've found I'll need to supply +12v, -12v, +5v, -5v, +3.3v, and a special +1.65v for a dedicated RAM PSU.
Is that correct?
As for current, though the PC isn't going to be using much power, I'd like to have a good supply on hand just in case I reuse it for something else in the future. So I'm looking at something like the Seasonic's 500-600w.
As for how, I was thinking to use AMB's Sigma 11 Linear PSU boards + toroidals for the single rails, and the Sigma 22 for the +/- rails. These PSUs are proven work horses and have super low ripple. This part of the build should be pretty straight forward, selecting voltages and then spec'ing the boards+toroidals to output it. However, how many toroidals and what size (voltage and physical) will I need to supply those boards?
One other problem I have is with getting the PC to start. From what I've read the ATX PSUs don't just simply go from either "off" to "on". There is a sequence that the rails need to go live in, and since I've got a dual-bios motherboard, one of the 5v lines actually goes off and on twice.
- So, what I need to make or scavenge is some kind of switch that will start up my DIY PSU in the same order so that the result is just 'push button' :-D
Recap:
1. What are the necessary rails that an ATX PSU needs to supply?
- and keep in mind that I need a dedicated 1.65v rail to supply the RAM.
2. How many toroidals, and of what size (voltage and physical), will I need to supply power to the various rails?
3. Where can I find, design, or make a switch/logic board to correctly supply the timing sequence of the rails during power on/off?
- I want to just connect the looms (24pin, 8pin, 4pin) and then use my DIY PSU with my audio PC as if it were a standard ATX one. Some quirks, sure, but nothing about opening the lid or pulling cables.
Thanks a lot, guys. That's it for the first volley, and I'm sure I'll have more as the project moves ahead.
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Seasonic make greats PSU with very low levels of ripple and efficient DC-DC desings .... I think is unnecesary build a DIY PSU, is really hard and you are missing a lot of stuff ....
I had problems too with electronic noise on my sound card, generated by the Videocards and hard-drives, solve it by adding capacitors on the card and changing filter capacitors of the PSU for a better ones.
I had problems too with electronic noise on my sound card, generated by the Videocards and hard-drives, solve it by adding capacitors on the card and changing filter capacitors of the PSU for a better ones.
An externally hosted image should be here but it was not working when we last tested it.
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Look at the current rating of the ATX supply you are now using.
3.3V at how many amps?
5V at how many amps?
There is a reason it is a SMPS.
As for noise from the SMPS: What frequency is the SMPS?
Are you saying that you can hear that frequency?
Does even 50mV of ripple on a 5V digital line cause the digital signal to be different?
IMHO the first place you should direct your energies would be the power supply to the sound card.
This is where analog is generated.
Thanks for the 2 responses, guys. Being into audio and DIY, I know that some things don't make a difference in the end, but that part of the point is the journey. I WANT to make a linear PSU for my PC and I HOPE that it sounds better. I don't WANT it to sound better and HOPE that I can make one. Know what I mean?
@ lexer98 - I don't specifically have a noise issue, I just hope to make it better. I also don't have any spinning anything in the PC. No fans, HDDs, disk drive, or fan on the PSU. So nothing to cut down on there. I do agree about putting capacitors on the rails, which I will be doing, but didn't want to get sidetracked on in this thread.
@ lexer98 - You also said I'm missing lots of stuff, like what? I'm all ears, so anything you can tell me is great.
@ DUG - What do you mean by "look at the current supply, there's a reason it's SMPS"? Are you trying to get me to notice that it's really high? If so, yes, I'm aware that the benefit of SMPSs is their high output current. And a downside to LPSs is their lack of current. That's why I need help in finding out what to do to get there.
The other thing is that I don't have a sound card. The PC is just a transport that outputs the music data via USB to my DAC.
@ lexer98 - I don't specifically have a noise issue, I just hope to make it better. I also don't have any spinning anything in the PC. No fans, HDDs, disk drive, or fan on the PSU. So nothing to cut down on there. I do agree about putting capacitors on the rails, which I will be doing, but didn't want to get sidetracked on in this thread.
@ lexer98 - You also said I'm missing lots of stuff, like what? I'm all ears, so anything you can tell me is great.
@ DUG - What do you mean by "look at the current supply, there's a reason it's SMPS"? Are you trying to get me to notice that it's really high? If so, yes, I'm aware that the benefit of SMPSs is their high output current. And a downside to LPSs is their lack of current. That's why I need help in finding out what to do to get there.
The other thing is that I don't have a sound card. The PC is just a transport that outputs the music data via USB to my DAC.
OK.
Look up high current low voltage linear regulators and that will point you in the right direction.
You will need high current low voltage transformers and some good rectifiers.
There is a stand alone synchronous rectifier controller IC that controls four FET's in a bridge rectifier application...I designed a board for it but can't find the part number (or where my files are). I don't know how low in supply it will go but it will really help with efficiency of high current supplies.
If you go too high in filter cap capacitance in an attempt to reduce ripple voltage beware of high peak currents in the transformer/rectifier path.
Use a star ground when connecting all of the supplies together. This will also be the exit point for all supplies.
Happy learning.
ps external DAC...good
OK.
Look up high current low voltage linear regulators and that will point you in the right direction.
You will need high current low voltage transformers and some good rectifiers.
There is a stand alone synchronous rectifier controller IC that controls four FET's in a bridge rectifier application...I designed a board for it but can't find the part number (or where my files are). I don't know how low in supply it will go but it will really help with efficiency of high current supplies.
If you go too high in filter cap capacitance in an attempt to reduce ripple voltage beware of high peak currents in the transformer/rectifier path.
Use a star ground when connecting all of the supplies together. This will also be the exit point for all supplies.
Happy learning.
ps external DAC...good
Thanks
I'm a big fan of the external DACs. I'm on my 3rd one now, a PS Audio PerfectWave Dac Mkii, after slowly moving up the scale. I'll be sticking with it for the foreseeable future, I'm very happy with it. It's partly why I've started my new journey to upgrade the parts that come before it to hopefully supply it with the best signal possible.As for the other things, thanks. I was actually hoping to use the AMB Sigma 11(single rail) or 22(dual rail) kits because they side step me having to learn about regulating the unregulated toroidals that I'll be needing.
The Sigma 11/22 is capable of being configured in almost any output under 36V, and I'll be needing nothing near there. As for current handling, their MOSFETs are rated at 18A, but I'll be shooting for ~10A for the 12V rail and less than that for the rest. In saying that, those are different ways of tackling exactly what you mentioned, right?
The star ground is a good tip and I'll have to keep it in mind. I only drawn out a general schematic of what I want to do, but haven't looked at grounding anything yet.
Sorry for the offtopic
Computer PSU have only 5 rails .... 5V , 3.3V , 12V , -12V and 5vsb.
5V, 3.3V and 12V ... power up the most parts of the computers (CPU, RAM, Chipset ect...) in modern computers the 12V rail is to become more important beacause supplying all devices that consume more energy as the CPU and graphics card. High-end PSU (>1000W) uses a DC-DC desing what means have a chopper transformer with only one winding which delivers .. 100A @ 12v or something like this, the rest of the voltajes are generated with regulators
-12V .. for the devices what need simetrical power supply , like onboard audio ... very low current no more than 1A
5vsb - that is the standby rail ... usually power up the USB and some other devices like ethernet ... arround 3.5A
All of the rest of the voltages like CPU , RAM ect ... are generated by a PWM Controler and mosfet in the motherboard.
You need to bypass two signal to get working the computer with your DIY PSU:
>"power good signal" grey cable that signal is generated by the monitor IC of the PSU, is a 5V signal with is measure by the motherboard ... if the signal lasts less than 500ms means that the PSU is OK ( Temperature, voltajes, current ect ...)
>PS_ON the green cable .. 5v is a signal that the motherboard connected to the GND when you push the POWER UP BUTTON and turns on the PSU
But you can remove a IC monitor chip from a cheapo PSU and use it or buy one
Example: http://www.fairchildsemi.com/ds/FA/FAN7680.pdf.
Read the ATX specifications for more information : http://www.formfactors.org/developer%5Cspecs%5Catx2_2.pdf
Good luck with your project
Computer PSU have only 5 rails .... 5V , 3.3V , 12V , -12V and 5vsb.
5V, 3.3V and 12V ... power up the most parts of the computers (CPU, RAM, Chipset ect...) in modern computers the 12V rail is to become more important beacause supplying all devices that consume more energy as the CPU and graphics card. High-end PSU (>1000W) uses a DC-DC desing what means have a chopper transformer with only one winding which delivers .. 100A @ 12v or something like this, the rest of the voltajes are generated with regulators
-12V .. for the devices what need simetrical power supply , like onboard audio ... very low current no more than 1A
5vsb - that is the standby rail ... usually power up the USB and some other devices like ethernet ... arround 3.5A
All of the rest of the voltages like CPU , RAM ect ... are generated by a PWM Controler and mosfet in the motherboard.
You need to bypass two signal to get working the computer with your DIY PSU:
>"power good signal" grey cable that signal is generated by the monitor IC of the PSU, is a 5V signal with is measure by the motherboard ... if the signal lasts less than 500ms means that the PSU is OK ( Temperature, voltajes, current ect ...)
>PS_ON the green cable .. 5v is a signal that the motherboard connected to the GND when you push the POWER UP BUTTON and turns on the PSU
But you can remove a IC monitor chip from a cheapo PSU and use it or buy one
Example: http://www.fairchildsemi.com/ds/FA/FAN7680.pdf.
Read the ATX specifications for more information : http://www.formfactors.org/developer%5Cspecs%5Catx2_2.pdf
Good luck with your project
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Alright, I've mostly got that stuff now. I also read up on 2 other super helpful links on getting an LPS powered mobo to post that were on Audio Asylum. From what I gathered, both routes are looking at an external switch for the 5V POWER_OK line. THe idea seems to work, but I'm REALLY looking to find an internal way for that.
There MUST be something out there that can mimic the necessary timing for that so that I can make a "push button" solution for this full power supply.
Secondly, what toroidal transformers do you guys recommend? I guess that I'll need a 12V @ ~+10A for the 12V and 5V rails, and then a smaller toroidal for the 3.3V and 1.65V rails. I have no idea where to buy from or what ones would be good/sound good here. Advice greatly appreciated.
There MUST be something out there that can mimic the necessary timing for that so that I can make a "push button" solution for this full power supply.
Secondly, what toroidal transformers do you guys recommend? I guess that I'll need a 12V @ ~+10A for the 12V and 5V rails, and then a smaller toroidal for the 3.3V and 1.65V rails. I have no idea where to buy from or what ones would be good/sound good here. Advice greatly appreciated.
10A is too little for your computer ... minimum a 12V @ 25A transformer and computers PSU don't have 1.65V rail that is generated by the MB
Simple solution is buying a Pico-ITX power supply ... something likes this 250W M4-ATX Smart Power Supply for Carputers ... and feed it with your lineal power supply
It is not a good sounding solution at all. Something similar to the Pico (Nano) prompted me to build a linear supply. Admittedly, for a very low power i3, but it made a very substantial difference soundwise. There was a thread about it somewhere...
If you are willing to change motherboards, ASRock has announced an AMD Kabini-based motherboard with 19V input.
AnandTech Portal | ASRock?s AM1 Kabini Motherboards Announced, including 19V DC-In Model
Zotac's Atom-based D2550-ITX-B also has 19V input (Zotac used to have a motherboard with 12V input that could be powered with SLA batteries, but I didn't find it now).
mini-itx.com - store - Zotac Mini-ITX Motherboards
And, Japanese manufacturer Fidelix is in the process of launching a low-noise power supply for notebook compouter applications (page is in Japanese, need to use a translator)
Power Supply
AnandTech Portal | ASRock?s AM1 Kabini Motherboards Announced, including 19V DC-In Model
Zotac's Atom-based D2550-ITX-B also has 19V input (Zotac used to have a motherboard with 12V input that could be powered with SLA batteries, but I didn't find it now).
mini-itx.com - store - Zotac Mini-ITX Motherboards
And, Japanese manufacturer Fidelix is in the process of launching a low-noise power supply for notebook compouter applications (page is in Japanese, need to use a translator)
Power Supply
I was talking about 10A on just the 12V rail. As long as I have separate supplies for each voltage I think that'll be OK. I don't have a GPU and the TDP on the i5 is 65W. 65W off 120W (12V @ 10A) should make for a nice, lazy demand. Then I'm looking at 5A on the 5V, 3A on the 1.65V, and 4A on the 3.3V.
As for the 1.65V, that's a dedicated supply for the RAM. The motherboard does supply that voltage to it because that's what they're rated at. I may have to cut into some supply, but I've read in a few places about the idea of direct supplying the RAM.
And the PICO, thanks for the idea, but since it's a switching supply, I'm going to stay away from it. Feeding linear right into something that's going to turn it into different voltages via switching isn't the plan I had in mind. It would be easy for start up timing, which I need, but wouldn't meet my other requirement.
Hey Analog, thanks for commenting in. I actually had your old thread open and finished reading it just before you posted. What a funny coincidence. From what I've read you're not alone in your experiences. Anyone who has taken the time to work the PICO out of their powering setup has claimed it made a difference for the better. I'm going down that path too.
Thanks for the links, I'll have to give my Japanese a run for it's money and see how much I can still understand
As for changing motherboards, I can't see myself doing it. I don't want the full form factor, but I do need the PCIe slots. I need at least 2 on the board for my cards, and possibly 3 for one I might get down the line. So there's not much room to move on that point. Thanks for the ideas, though.
FIRST ! ... COMPUTER PSU DON'T HAVE ANY 1.65v RAIL (I wrote it three times)
The MB, IGP and peripherals consume energy .... TDP (thermal design power) is the maximum amount of heat that can generate CPUdoes not mean that the CPU consumes 65W, indeed your PC with the CPU at Full Load @ stock speed should consume arround 90-100W.
Funny, right? I suppose I'd compare it to saying, I'd rather stick with just getting punched in the face(onboard mobo switching circuits) then adding getting kicked in the bag(additional switching supply, PICO) as well.
Thank you, Lexer98. I guess I don't know as much as you do about computer electronics and I've used the wrong terms. Please read the following link to see what I'm talking about with the 1.65V going to the RAM.
Audio Asylum Thread Printer
What you will find is that someone has independently powered their RAM via a linear power supply, just like I had said I wanted to do. I am aware that there is no socket (like P24 or P4) to plug this rail into, but I will make it none the less and patch directly into that section of the motherboard, just as the other poster did in the link. Do you understand what I mean now?
Besides that, I have looked on the AMB site at the Sigma11 and Sigma22 threads and will be using 3 Sigma 11's to make the 5V, 3.3V, and 1.65V and then 1 Sigma 22 to make the +/-12V.
The for toroidal transformers for the power, I'm still trying to figure it out, but have so far found something like this:
Transformer #1.
30VCT (15v-0-15v) @ 10A (from Primary)
10V in parallel @ 7A or 5VDC (from Secondary)
Transformer #2.
9V in parallel @ 5A or 3.3VDC (from Primary)
8V in parallel @ 3A or 1.65VDC (from Secondary)
I'm still trying to understand the actual Primary and Secondary output part, but I've contacted a custom toroidal manufacturer and explained what I'm looking for, so hopefully he can correct any misconceptions I have. Feel free to do so here, though, in case you see something out of place.
I really hope I can squeeze all that out of just 2 toroidal transformers, I really don't want to have to use 1 toroidal for each voltage. It would destroy my plan for the case I'm looking at using that comes from the same line as my Audio PC case. It's an extruded aluminum one.
Sure - it is your hobby after all, and I guess "if it is worth overdoing, it is worth overdoing" applies.
Looking forward to your results - are you planning on posting any "before" and "after" measurements?
So, to understood well, you have an external DAC connected by USB?
On computer you work only with digital signals?
Do you know one of the big advantage of digital signals? The noise imunity. This mean that the signals are not afected by noise up to over 2V for 5V powered circuits. The noise from your power supply are under 100mV for a good power supply (like your Seasonic).
Switching to a linear power supply it is useless. Improving in sound can come only from ground noise that are inserted on external DAC by a SMPS supply comparing to a linear supply.
You need only to use a USB optical isolator. It is more cheap and the improving it is bigger because will reject the noise generated by rest of noise sources from a PC.
Using a USB optical isolator you will not hear any differences between a SMPS and a linear power supply. Or...... you can use a external opticaly isolated DAC.
On computer you work only with digital signals?
Do you know one of the big advantage of digital signals? The noise imunity. This mean that the signals are not afected by noise up to over 2V for 5V powered circuits. The noise from your power supply are under 100mV for a good power supply (like your Seasonic).
Switching to a linear power supply it is useless. Improving in sound can come only from ground noise that are inserted on external DAC by a SMPS supply comparing to a linear supply.
You need only to use a USB optical isolator. It is more cheap and the improving it is bigger because will reject the noise generated by rest of noise sources from a PC.
Using a USB optical isolator you will not hear any differences between a SMPS and a linear power supply. Or...... you can use a external opticaly isolated DAC.
Sure - it is your hobby after all, and I guess "if it is worth overdoing, it is worth overdoing" applies.
Looking forward to your results - are you planning on posting any "before" and "after" measurements?
Now you can see what I'm thinking
I've definitely gone far past any "normal" approach; absolutely into the "overdoing" zone.As for measurements, I'd love to. I have no idea how, though :-/ The only thing I guess I could do is take listening notes on a range of tracks on a few separate occasions beforehand, just to establish a sort of baseline. Then take listening notes on the same ones a few times afterward and see if they're the same. Not great, but I'm not sure of another way.
Any suggestions?
Yes, this is exactly how I have the system set up. I have a PS-Audio - PerfectWave DAC Mkii, connected via an iFi Micro - iUSB Power. This device provides galvanic isolation.
Although I can't speak for it as I haven't tried myself, but many who have tried a USB optical isolator (like the Adnaco S3B) have said it's better than a regular motherboard USB connection, but not better than some specialty, linear powered USB cards; most of which cost less than the Adnaco. They claimed a lack of timbre, realism, or nuance to the music, in comparison.
Again, I can't say for myself, but that's the word on the street. Thanks for the heads up, though.
Yes, I understand that this effort may not bear any fruit. I want to try anyway. If I can fit this DIY power supply into the chassis that matches my Audio-PC, then it'll look like a premium component. AND I'll know that I DID IT.
Thank you for the advice, I understand you're trying to save me A LOT of time, trouble, money, and heartache. It's just like I mentioned earlier, though. I've decided to do this and I'm looking for advice how. I hope in the end it makes some difference, but that's not the purpose of this DIY, just a hopeful side-effect :-D
Sorry for answer so rude, sometimes my screws get out
.... Powering the RAM with a linear PSU don't have ANY advantage and don't affect the audio ..... In fact is worse because you lose the BIOS control and complicate the things
The only thing that can affect the audio are the power circuit of the CPU, chokes oscilate at 300-400Khz, but your MB is a really good one, usualy cheapo motherboard or bad designed add noise in the onboard audio or sound card (Some models of EVGA )....
In my opinion don't change anything related with the MB.
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