cheap/chinese LPSU's - minefield?

[barrows]

Simple, do not purchase cheap Chinese power supplies.  Instead, purchase a high quality supply from a reputable company/builder, who you trust.

Look, you do not really "need" these at all as most who are looking to purchase a linear power supply are doing so to replace a cheap SMPS, so if you really want an upgrade, get something good.  Just because a supply is linear does not mean it is good!

 

Additionally, the s11 power circuit used by some of the supplies mentioned above is stolen intellectual property, do not support companies that steal other's work, it makes you an accomplice to theft.

 

Also, if one has enough knowledge to determine if a given Chinese supply might actually be good, then that person has enough knowledge to build their own power supply, and i would highly recommend doing that, as then the user can build a power supply ideally suited for their load and its requirements.

The Chinese use counterfeit parts, poor PCB quality, and usually, barely adequate designs.  If one is looking for an upgrade, get something of quality.

[barrows]

8 hours ago, the_doc735 said:

these are quite serious allegations to make! please don't put yourself at risk of a 'LIBEL' court case from china! Do you have any proof/evidence to back up your case? OR, do you expect people to believe your word alone? take care.

As to the use of counterfeit parts in China I have direct experience of it, it is commonplace and well known in the industry.  As i did not point out any specific product, there is no risk to me.

As to the use unauthorized use of AMB labs' intellectual property see this quote from their website:

 

• "There are "σ22" clone boards being offered for sale on ebay and elsewhere. They are inferior in quality, made without permission and a violation of the terms set forth on this website. AMB urges not to patronize those unscrupulous vendors."

I would recommend going to the AMB labs website, they offer some very good power supply designs for DIY with full instructions and they sell PCBs for them, and they also provide info for builders who can build their designs for you, but if you have some free time, learning to DIY is not that difficult for projects like these, and with their excellent instructions.

 

https://www.amb.org/audio/

 

They do not license their designs to Chinese vendors, so anything using a sigma11 circuit would be unauthorized.

 

[barrows]

7 hours ago, jabbr said:

I do do love the Salas Shunt for analog and Reflektor-D for digital and if anyone wants to build, the boards/kits are available through DIYAudio.com 

While I have used Salas' shunt regulator designs quite often (and they are excellent) I would not really recommend them for things like a computer server, or a renderer, as these devices have a very wide range of current consumption, where they may require a very high initial current to boot up, and then the current use drops way down.  With a shunt you have ti set the CCS high enough to meet the boot up current demand, problem being that when the current use drops the heat level goes way up.  While it is possible to use them for this, it will generally require enormous heatsinks to keep things from releasing smoke.

IMO a better option for powering these types of devices is a linear-series style reg, like sigma 11, etc.

 

As to the meaning of "open source" my understanding is that for AMB designs, this means they are free to use for individuals, but not for commercial purposes.  Considering the effort put in by the designer in maintaining the website, designing and selling PCBs, and the very, very detailed instruction and support provided there, if it is not illegal to copy their designs, it is certainly very bad form and to be frowned upon.

 

Now I do not subscribe to the life approach "if I get away with it is OK", I know some people do that, but we should all be better humans than that.

[barrows]

4 minutes ago, Ralf11 said:

 

 

?? your avatar shows a snowboard on your back, and you live in a high avalanche area

Sounds off topic, but yes, i am an avid backcountry snowboarder and I deal with avalanche risk evaluation and avoidance on a regular basis.

[barrows]

3 minutes ago, jabbr said:

What evidence do you have that they copied the AMB design? Why are you saying that

Perhaps i am mistaken.  lookandlisten described the circuit as sigma11 in this thread, if it is not then that is another thing.

 

I am well aware of the Chinese tendency to revise engineer most of the designs which come out of China, everyone in the industry deals with this on a regular basis, so if it is a direct copy I am not surprised, but perhaps I misunderstood lookedlisten's post.

 

I have also seen the notifications at AMB labs' website warning of the clone PCBs available on eBay.

[barrows]

23 minutes ago, the_doc735 said:

well done, sounds like you are a rescuer?

No, I ride in the backcountry two to three days a week and this requires constant evaluation of the snowpack, weather, etc.  And of course in the event of an accident, I become the rescuer (or the victim, as the case may be) it is up to the individuals of the team to self rescue, waiting for outside rescue in avalanche burial = body recovery.

 

Sorry for the OT folks, back to your usual programming!

[barrows]

1 hour ago, jabbr said:

Right but consider this: https://patentimages.storage.googleapis.com/4a/5d/02/fb481b20f81835/US5955915.pdf

patent from 1999

(including figure 2 which is prior art)

I am just going to respect this statement printed at the AMB labs website:

 

"Copyright © Ti Kan, 
All rights reserved. Commercial use of this design is prohibited without prior permission."

 

I understand that similar (but not identical) circuits have existed for a long time, still, it would appear to me that marketing a commercial product as sigma11 is in direct violation of the above, at least in spirit if not legally.  The violation of that spirit alone is enough for me to accept that it is wrong.

[barrows]

1 hour ago, look&listen said:

Recall one seller respect AMB enough to name source, others imply source with product naming (S11)

@jabbr,  The above quote suggests to me that these companies are marketing the product as "sigma11", am I reading this wrong?

 

Sonore designs and builds are own products.  John Swenson does our high speed PCB design and I do the power supply design (schematic/protos) and internal layout, and we use a sub contractor to layout the power supply boards.  We also use a small processor daughter board from a third party supplier, which mounts to the main board, as developing this ourselves, while possible, would add no benefit to our products, but would raise the price due to the development time involved.  We also use our own, proprietary OS (which has been copied without permission by various competitors), and have our own proprietary web based interface for configuring our products.  Our top level products (Signature Series) are hand built, one at a time, personally by me at Ice Station Zebra in Colorado.  The custom chassis for our Signature series products are designed by our VP, and manufactured in California.

[barrows]

I am never one to discourage those who are interested in learning to DIY a bit, but a multiple rail, relatively high power,  AC based power supply is not the place to start.

If one is really interested in learning to DIY some power supplies, i would recommend starting with something simple, where there is adequate support.

AMB.org makes some very nice power supply designs available, single and dual rail, and these are adaptable to many different projects.  They also have a forum with very good support, and very good instructions.

Twistedpearaudio.com is another company with DIY designs and complete kits, with forum support at DIYaudio.com.

There are many folks at DIYaudio.com who offer a lot of support for those interested in learning as well, in general.