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the_doc735

cheap/chinese LPSU's - minefield?

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6 minutes ago, jabbr said:

You should also realize that most boards — including motherboards and PCIe cards and drives have onboard DC/DC converters eg 3.3, 2.5, 1.8 and 1.1V so your quest to entirely eliminate SMPS may be rather difficult unless you move to a renderer.

Many thanks!   ..but I have already been told this dozens of times and I am aware of the situation already! Apparently Zenith can by pass the switching on their supermicro mobo's? (somehow?) ...intriguing !

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51 minutes ago, jabbr said:

You should also realize that most boards — including motherboards and PCIe cards and drives have onboard DC/DC converters eg 3.3, 2.5, 1.8 and 1.1V so your quest to entirely eliminate SMPS may be rather difficult unless you move to a renderer.

Additionally. the idea was to reduce/minimize ripple with LPSU, not eliminate altogether due to the mobo onboard converters. Sort of "give it every chance" of success. i.e. "well at least start with a clean power source, not add to what is already onboard the mobo" as well. Don't make it any worse than it needs to be!

I have considered that an el cheapo LPS could make things worse, than with my Flagship Seasonic ATX. But like you said: "try it for yourself and determine what is best suited to your setup." As for Supremo LPS, I have no idea what that would accomplish? Could be a big "white elephant"! And then there's those iFI iPOWER things with 1uV ripple?

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@Kelly said:

"Some very established but forward looking companies are using SMPS in their units. All the latest NAD master series is SMPS and I believe Linn also uses SMPS in all of their products. I know my Kii Theee speakers use SMPS power supplies. I believe the main problems with SMPS implementations is  that they emit a lot of noise back into the power mains if care is not exercised to prevent it. So that is why an accessory linear supply may sound better than an SMPS even if it does not provide cleaner output in a lot of subjective tests: the linear supply does not crud up the mains for the rest of the system."

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@Superdad:

 

....so, what is your take on all this SMPS revival and enthusiasm?

Surely as a LPSU vendor you have some thoughts to vent?

If everyone went 'PRO' SMPS and you had no LPSU sales, what would your thinking be on the subject?

 

Cheers!

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3 hours ago, jabbr said:

You should also realize that most boards — including motherboards and PCIe cards and drives have onboard DC/DC converters eg 3.3, 2.5, 1.8 and 1.1V so your quest to entirely eliminate SMPS may be rather difficult unless you move to a renderer.

You and @sandyk : ...have some serious assumption issues to deal with:

1) I never said I wanted to entirely eliminate SMPS switching noise/ripple! Realistically my aim is to reduce the noise and not to totally eliminate it, I fully understand that mobo's have SMPS conversions onboard. 

2) Please note: when I talked about building a LPSU, I was talking about buying a COMPLETE PCB & COMPLETE R-CORE TRANNY! i.e. not designing and building the PCB myself; and allowing the PCB provider to supply a matching tranny, based on the device it was powering. e.g. NAS/PC/Renderer/ Router/FMC/NAA etc. 

3) I never said I wanted to become a PCB designer and/or builder! I take pre-assembled components and fully build them up; "an assembler" NOT circuit designer & builder.

Record 'straight'!

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On 9/27/2018 at 6:44 PM, jabbr said:

...and don’t tell me that you already know about electronics because you’ve been doing it for 42 years because if you understood what you were doing you could figure out what transformer you need.

I am not a PCB designer or builder AND I HAVE NO DESIRE TO BE ONE! For the last 40 odd years I have know enough to get me by; by replacing worn out parts from fridges, washers, cookers, TV's, cars etc etc. I do not want to become a electronics builder and designer, I have no desire to learn this discipline! I am happy repairing things and my family and friends are grateful for free repairs (when it works - LOL!). My knowledge is basic and there is no shame in that respect! I asked the PCB supplier to provide a suitable tranny, based on the intended appliance it was going to power.

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Thinking about buying a 4 rail lps to my music computer and also to act as energizer for two lps-1 and to power a nano iusb3.0 and a ssd. 

 

Has anyone any experience with this 4-rail lps or could give som input about it? 

https://www.aliexpress.com/item/ZEROZONE-Finished-4-way-High-Current-Hifi-linear-Power-supply-DC5V-9V-12V-19V-LPS-L4/32884191103.html?spm=2114.search0104.0.0.39f32788g4KlpS

 

HDPLEX has also released a new version of their 200w lps with 4X LT30451 for the two adjustable rails. The ripple measurements seems acceptable for the adjustable rails around 300uV at full load. But the  12V seems little higher ripple around 1.5mV at half load. For the 19V rail there is no youtube video or info so I dont know the ripple for that rail but probably higher than the 12V rail.

 

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50 minutes ago, henke said:

Thinking about buying a 4 rail lps to my music computer and also to act as energizer for two lps-1 and to power a nano iusb3.0 and a ssd. 

 

Has anyone any experience with this 4-rail lps or could give som input about it? 

https://www.aliexpress.com/item/ZEROZONE-Finished-4-way-High-Current-Hifi-linear-Power-supply-DC5V-9V-12V-19V-LPS-L4/32884191103.html?spm=2114.search0104.0.0.39f32788g4KlpS

 

HDPLEX has also released a new version of their 200w lps with 4X LT30451 for the two adjustable rails. The ripple measurements seems acceptable for the adjustable rails around 300uV at full load. But the  12V seems little higher ripple around 1.5mV at half load. For the 19V rail there is no youtube video or info so I dont know the ripple for that rail but probably higher than the 12V rail.

 

this might interest you?

https://www.computeraudiophile.com/forums/topic/46284-lpsu-choices/?page=2&tab=comments#comment-881339

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Yes seems we are on the same quest about finding a linear lps for the pc. :)

 

Im leaning towards going with the hdplex 200w + 400w hifi atx dc converter. It seems safer than going with chinese ones.

 

I think I have sufficient isolation from the pc with one iusb3.0 at pc usb port and two iso regens driven by lps-1 + singxer su-1 driven by hynes sr-4. Maybe overkill but the second iso regen actually calmed the sound down quite a bit and added to overall sound quality.

 

But I want to get rid of all polluting smps from my music system which consistst of evga supernova p2 atx power supply + 2 ifi ipower and 2 meanwell smps to the lps-1:s.  

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43 minutes ago, henke said:

Yes seems we are on the same quest about finding a linear lps for the pc. :)

 

Im leaning towards going with the hdplex 200w + 400w hifi atx dc converter. It seems safer than going with chinese ones.

 

I think I have sufficient isolation from the pc with one iusb3.0 at pc usb port and two iso regens driven by lps-1 + singxer su-1 driven by hynes sr-4. Maybe overkill but the second iso regen actually calmed the sound down quite a bit and added to overall sound quality.

 

But I want to get rid of all polluting smps from my music system which consistst of evga supernova p2 atx power supply + 2 ifi ipower and 2 meanwell smps to the lps-1:s.  

Jabbr said:

 

"You should also realize that most boards — including motherboards and PCIe cards and drives have onboard DC/DC converters eg 3.3, 2.5, 1.8 and 1.1V so your quest to entirely eliminate SMPS may be rather difficult unless you move to a dedicated renderer."

 

Please remember the new '200' goes down to 800 uV (microvolts) ripple, but the 400w hifi ATX only achieves 10mV (millivolts) ripple, so you would be re-increasing the noise by putting the 400 after the new 200!

 

more worrying in this picture is the continued use of a crappy full wave rectifier!

 

809381100_HDPlexnew200elnaaudiocapactors1.thumb.jpg.b14ff910ed29477e59aa32d49a554bb7.jpg

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40 minutes ago, the_doc735 said:

Jabbr said:

 

"You should also realize that most boards — including motherboards and PCIe cards and drives have onboard DC/DC converters eg 3.3, 2.5, 1.8 and 1.1V so your quest to entirely eliminate SMPS may be rather difficult unless you move to a dedicated renderer."

 

Please remember the new '200' goes down to 800 uV (microvolts) ripple, but the 400w hifi ATX only achieves 10mV (millivolts) ripple, so you would be re-increasing the noise by putting the 400 after the new 200!

 

more worrying in this picture is the continued use of a crappy full wave rectifier!

 

809381100_HDPlexnew200elnaaudiocapactors1.thumb.jpg.b14ff910ed29477e59aa32d49a554bb7.jpg

Yes thats disturbing I think that my current evga p2 650 has around 5mv on all voltages at the around 55w load the computer draws when upsampling to dsd512 in hqplayer. So in that sense it is not good. It would be nice to see some real measurements of the 400w hifi atx. Is 10ms the lowest it can achieve if so it could go up drastically when load increases.

I guess one can order the lps and hifi atx and return it if there is no improvement, the return policy seem very generous.

""No question asked exchange: Within a year from the delivery date. 

- Items are not damaged, abused, or missing accessories. 

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2 hours ago, henke said:

Yes thats disturbing I think that my current evga p2 650 has around 5mv on all voltages at the around 55w load the computer draws when upsampling to dsd512 in hqplayer. So in that sense it is not good. It would be nice to see some real measurements of the 400w hifi atx. Is 10ms the lowest it can achieve if so it could go up drastically when load increases.

I guess one can order the lps and hifi atx and return it if there is no improvement, the return policy seem very generous.

""No question asked exchange: Within a year from the delivery date. 

- Items are not damaged, abused, or missing accessories. 

I think maybe they are stating 10mV as a maximum figure?

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i think despite being sold under different names, are either made in the same place, if not identical, because the internal photos, and cases look so similar. Notable for the easily identifiable R-core transformer. I haven't spent too much time thinking about these nor measuring them because I generally use as a "pre-regulator" to supply a better on-board regulator. 

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5 hours ago, JohnSwenson said:

Here is some (maybe unwelcome) details on switching supplies etc.

 

First off there are two very different types of "switching things": The ones that plug into a wall (ie the input is AC mains, 120/230V AC, 50/60Hz), and ones you find on a board which take DC in (say 12V) and output DC (usually lower voltage).

 

These behave quite differently and I think it is important to not ascribe the same properties to both.

 

The AC line input ones I'm going to call "SMPS", the other I'm going to call "switching DC/DC converter", you can also call this a switching regulator.

 

An SMPS takes the raw AC line and switches it, breaks it up into tiny time slices, since this is slicing the AC line, it the amplitude of these slices is still going up and down at line frequency.  The frequency of the slices is somewhere between 30KHz and 100KHz. A lot of old ones worked at 30KHz but modern ones seem to like 60KHz. On the other side of the transformer there is a diode bridge, and caps and some circuit that measures the voltage.The output of the voltage sensor is fed back to the circuit that slices the line voltage which modulates the slices so that on the other side you get pretty flat DC. So you don't need the giant capacitor banks to smooth out the line AC, as the line voltage goes up, less power is sent to the transformer, and as the line goes lower more power goes to the transformer.

 

So why even bother doing all this? Primarily is the reduction in size, weight and cost of the transformer, and also the vast reduction in capacitors after the diode bridge. Line transformers have to be large heavy and expensive to work at 50/60 Hz. The transformers that work at the high switching frequencies are much smaller, cheaper and lighter weight.

 

The switching DC/DC converter takes DC in, slices it up and feeds an inductor with the pulses (note: NOT a transformer). These frequently run in the 400KHz to 1MHz range. Again a sensor looks at the output voltage and adjusts the slices to get the output voltage required.

 

Again why do this? Primarily because switching DC/DC converters conserve POWER and linear regulators conserve CURRENT. So waht does this mean? Lets look at a linear regulator, lets say the load is pulling 1 amp, this means the input current is also 1A. If you have a large voltage across the regulator you have to dissipate a lot of power. If your input is 12V and your output is 1V at 1A, the input is 12V at 1A, so 12W in and 1W out, that means the regulator has to burn up 11W!! The switching regulator is constant POWER, the input power is the same as the output power, thus for above  the input is only 1W instead of 12W, the current is 1/12 W. Non of these circuits are perfect so there is SOME power lost in the switching regulator, usually not very much.

 

The "noise" that comes out of an LPS and an SMPS are very different. An LPS with a decent regulator has broadband noise usually measured in micro-volts (uV), the best ones are around 1uV, the worst can get up to 60uV. If you look at this on a scope you usually see a flat line, you have to increase the gain dramatically to see this noise. An SMPS (and DC/DC converter) have ripple at the switching frequency, usually measured in milli-volts (mV), this is much easier to see on a scope, but is very hard to see using normal settings. Say you have a scope set to measure 12V,  you will see a flat line, 20mV won't even show up on that line. You have to go to AC coupling and turn the gain up. Not as much as with a LPS, but still a lot more than a normal setting.

 

In most circumstances either of these noise levels is not going to make any difference, since almost everything you are powering with an external box, will have their own regulators, THOSE are what really matter.

 

Now there are two other aspects of a power supply that DO seem to have an affect on what is powered, they are a lot harder to understand than noise, and nobody ever puts measurements for these in a spec sheet so there is no way to compare. These two things are output impedance and leakage current.

 

The output impedance is what the voltage does when a change in load current happens. This is particularly important for quick changes in load current. Slow gradual changes can easily be handled by the PS, but quick changes cause the output voltage to change, frequently it will then slowly recover to the original value. This is most important for devices like computers which have large, quick changes in current draw. In many cases the regulators in the device can't handle this voltage change either and it winds up getting to the circuitry.

 

There is no generalization about this with LPS VS SMPS. Both types have some that have very low output impedance (this is good) and some have high output impedance. Since nobody measures this or puts it in spec sheets there is no way to know. The only correlation seems to be that the specialty, expensive LPS tend to have very low output impedance. I have done a bunch of measuring of PS and have found some SMPS that beat a lot of the less expensive LPS. But you can't tell which they are, they don't look any different, they don't cost more, they just are better. BTW some of the SMPS that are touted as being low noise have horrible output impedance.

 

The other property is leakage current. I'm not going to go into details on this, I have written tons of posts on this. For this there is a BIG difference between SMPS and LPS. The both have leakage, but the type that comes from an SMPS seems to be much more damaging to digital audio than what you get out of an LPS. The SMPS DO vary a fair amount, again hard to tell which are the lower ones. The largest amount of leakage I have ever measured is from an SMPS that talks about how low its noise is.

 

A switching DC/DC converter does not generate leakage, it does not STOP leakage, but it does not generate its own. If a switching DC/DC converter is fed from an SMPS, whatever that SMPS produces is what will be on the output of the converter.

 

One thing about SMPS that is talked about a lot is noise from the SMPS being "backwashed" into the AC mains. This used to happen many years ago, but modern SMPS don't seem to have this issue at all. Because this is something people can understand I think this gets the credit when I think in most cases the real culprit is the leakage current.

 

So what does all this mean for a computer? The primary effect from powering a computer from an LPS seems to be the reduction in leakage current, NOT ripple on the output of the supply. There are fairly inexpensive ways to deal with leakage current, so in most cases using LPS ATX supply is mostly wasting money.

 

If you have a computer directly driving a USB DAC there are some waysto prevent most of the leakage from getting through. But in my opinion a better way is to use a renderer powered from an LPS. In this case all you have to do is prevent the leakage coming over the Ethernet connection from getting onto the USB connection. Fortunately this is very easy to achieve and quite inexpensive.

 

So the upshot is that you can achieve most of what advantage there is in using an ATX LPS in other ways for a LOT less money.

 

John S.

wow john! great!

the mind boggles !

I have 3 projects ongoing.

What I am concentrating on the most is:

 

"synology NAS (with SOtM filters), zyxel router,  tp link optical section, microrendu 1.4, ultradigital i2s, LKS 004 DAC, J.Wood valve amp, monopulse AC Reference speakers + active BK sub XXLS400.

 

I am very indecisive concerning how to power 'this lot', and whether your smps grounding trick is of any value here? Which way to go: SMPS, LPS. batteries...? Copper, silver cables...? I am already convinced that power supply selection DOES affect the sound quality! All advice is much appreciated!

 

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22 minutes ago, marce said:

WIth digital power delivery systems there is a lot more than just the main power supply, though that is important, what is more important is the care laying out the circuitry with the local decoupling, point of load power. Get that wrong and no front end is going to help, you will get increased noise, especially simultaneous switching noise and more ground bounce.

Here is a PDF from a course on PDS, SIV and EMC that I did in Germany a few years ago. It will hopefully give you and others a bit more understanding of the noise mechanisms at play and issues on solving them as well as how to design a PDS. Its got pictures which I always fine easier than words to get to grips with all this stuff, picturing the wave fields round signals shows how interaction happens, magnetic its just basic Maxwell. Sorry it is a bit software orientated but it does have relevant info. Did a week of this in a heatwave in Munich!!! Staying awake was an issue in the afternoon after a large lunch and wine! The cafeteria had beer and wine on offer as well as amazing food.

02_PIA_Architecture.pdf

thanks for the pdf. I would need to read that several times for it to start making sense and 'sink in' (LOL!). Thanks for taking the time and trouble to do this as I also find pictures easier!

It's mainly the stuff from the start of the chain, up to but not including the DAC.

 

"synology NAS (with SOtM filters), zyxel router + 'O.N.T',  tp link optical section (x2), microrendu 1.4, ultradigital i2s, LKS 004 DAC, J.Wood valve amp, monopulse AC Reference speakers + active BK sub XXLS400. 

 

The DAC has its own 2 toridal transformers.

Obviously the valve amp doesn't need a wall wart!

The  sub has its own plate amp & power.

 

I  have: a Tacima CS947-6 way, & Power Inspired AG1500 AC regenerator + Eaton TPC2105-2780 8 Outlet 1u Rackmount PDU.

The Missing Link - Silver Plated UK Double Wall Socket Unswitched. APC PM1W-UK. silver plated plug MK 655 audio grade. MCRU - SILVER IEC mains power connectors. Meterware ViaBlue x25 silver power cable. 230V AMR Gold Fuses. 

+ A.... 'SH*T LOAD' OF CHEAP WALL WARTS FOR ALL THIS STUFF!

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I posted it because we often talk about noise, so its nice to see how its created and how it couples. High speed digital not so bad, all the microwave stuff that;s appearing is a different ball game all together, for the high end stuff your looking at 2mm+ wall thickness for shielding...

As things get faster the noise margin decreases, the positive from this is motherboards have to have a better PDS and less noise just to operate, unlike the old clunky PC;s of yesteryear that could tolerate crappy SMPS's.

 

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21 hours ago, marce said:

I posted it because we often talk about noise, so its nice to see how its created and how it couples. High speed digital not so bad, all the microwave stuff that;s appearing is a different ball game all together, for the high end stuff your looking at 2mm+ wall thickness for shielding...

As things get faster the noise margin decreases, the positive from this is motherboards have to have a better PDS and less noise just to operate, unlike the old clunky PC;s of yesteryear that could tolerate crappy SMPS's.

 

That's spot on!  ...all this PSU stuff is in an effort to reduce noise as much as possible. For example, john swenson has said that the LPS 1.2 (with the caps) is just as well supplied by a SMPS as it would be with a LPSU, maybe even better with 'the right' SMPS? I believe it even comes with a SMPS that has the high impedance noise fix built-in?

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