[Guide] Homebrew powered risers.
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[quote author=ghostlander link=action=profile;u=448 date=1386650016]
[quote author=lbr link=action=profile;u=24747 date=1386624022]
Hello,For some reason I can’t post in the thread(prly cause I’m just registered).
[url=http://forum.feathercoin.com/index.php/topic,2193.msg17391.html#msg17391]http://forum.feathercoin.com/index.php/topic,2193.msg17391.html#msg17391[/url]
[quote]Ohm’s law disagrees with you. Path from power connectors on mainboard to other PCIe slots has much lower impedance.
[/quote]
Plz define “much lower”?
I mean… ok, voltage drop will occur, so what if it’s not too high? Right?
And for multiple PSU usage… cutting is absolutely must, right?[quote]It isn’t clean enough. Bulk capacitors inside PSU are capable of basic low frequency filtering only. Additional capacitors at loads are required. PCIe ribbon extenders (these are not risers) add considerable amounts of impedance to power rails. That includes earth. Good quality capacitors don’t bulge.
[/quote]F.e. CoolerMaster-SIlentProM 1000W PSU, second line caps are 16v 1600uf, low esr ones.
Imo they are good enough for not only low frequency filtering…
or… there should be some low capacitance film caps as well?If caps should be added on riser, which ones?
I assume some solid 16v?Also, why exactly caps at loads are required?
Thanks
[/quote]Make one post in the forum for newbies first. Much lowe is significantly lower. It depends, but the difference may be high. Multiple PSUs are fine as long as you synchronise them properly. 1600uF/16V are not good for HF as they’re liquid electrolytes. Solid or polymer tantalum are good. Watch the polarity as tantalums explode if reversed.
[/quote]
Thanks for your reply.
Sorry for asking so much questions, but you are the first person I’ve seen on digital currencies forums who actually has some technical understanding of electricity ; )Ok, how do I measure impedance?
I can use digital testers, analog oscilloscope.
Impedance is resistance under voltage applied, right?
What do you mean by “synchronise them properly” on/off sync?I always cut my risers in fear that +12v PSUs lines will “meet”… and nothing good happens ; )
Was my assumption right?Hm, what if I took two oscilloscope readings - from PSU +12v line and from motherboard +12v line, would it help to determine which caps exactly are needed to be soldered on the riser?
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[quote name=“ghostlander” post=“17356” timestamp=“1372081622”]
2. Attached +12V but no earth. Bad. Additional capacitor or even two can be also useful.
[/quote]so… riser should also have thick-enough earth wire connected to PSU earth?
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It’s a bit complicated to measure very low impedance with consumer grade digital multimeters. We’re talking about DC, so R=U/I. The PSUs are synchronised if they can be powered up by a single button and don’t interfere with each other. It’s not good to have rails crossed of the same PSU. It’s even worse to have them crossed of different PSUs. A good scope is what you need to check for power supply quality. It’s a matter of thumb to place capacitors as close as possible to the point of load. Small HF capable capacitors come first, bulk electrolytes come last.
[quote name=“lbr” post=“42649” timestamp=“1386704212”]
[quote author=ghostlander link=topic=2193.msg17356#msg17356 date=1372081622]
2. Attached +12V but no earth. Bad. Additional capacitor or even two can be also useful.
[/quote]so… riser should also have thick-enough earth wire connected to PSU earth?
[/quote]Yes. All power wires should be as thick as you can afford. We are not into a mass production, so the extra cost is negligible.
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[s]So for 1x-1x riser scenario is absolutely the same, right?
Mission accomplished?
[url=http://www.ebay.com/itm/25CM-PCI-E-1x-To-16x-Riser-Card-Ribbon-Extender-Extension-Cable-With-Molex-Power-/201002973530?pt=LH_DefaultDomain_0&hash=item2eccb5f95a]http://www.ebay.com/itm/25CM-PCI-E-1x-To-16x-Riser-Card-Ribbon-Extender-Extension-Cable-With-Molex-Power-/201002973530?pt=LH_DefaultDomain_0&hash=item2eccb5f95a[/url]And the one with capacitor? Now after some time do you think the caps are needed?
[url=http://www.ebay.com/itm/4PIN-Molex-Power-Filter-PCI-E-Extension-Cable-1x-16x-Extender-Riser-Card-Adapter-/181151058265?pt=LH_DefaultDomain_0&hash=item2a2d71c959]http://www.ebay.com/itm/4PIN-Molex-Power-Filter-PCI-E-Extension-Cable-1x-16x-Extender-Riser-Card-Adapter-/181151058265?pt=LH_DefaultDomain_0&hash=item2a2d71c959[/url][/s]Screw this… I go for 16x-16x riser (4USD) and will fully follow Nut’s instructions.
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[s]nutnut, will you update your guide with how to add eathing to the risers?[/s]
edit:
So after my serious brain fart and meltdown, I figured out the right sentence structure;
Nutnut, will you be updating your guide with how to add grounding to the home-made risers? -
I’ve order some ‘normal’ risers so i am going to read this topic carefully soon!
Added the guide to:
[url=http://forum.feathercoin.com/index.php/topic,685]http://forum.feathercoin.com/index.php/topic,685[/url] -
Any chance this could be compressed into one page, I’ll edit into the pinned guide in mining, if required?
I found it confusing what was decided safe at the end. Possibly room for someone to do a Youtube / Blue Peter “video how to”.
I just use a riser, but I like to see steam punk solutions.
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Anyone has any objections to the following -
Ideal riser should be
0*) PCIEx16 -> PCIEx1, cause mining does not require bandwidth and x1 link theoretically puts lower strain on the mg chipset/CPU.
Tho some motherboards will require presence shorting if x1 risers are used in x16 slots.-
“cut” - to prevent current flow from/to motherboard voltage regulatorsPSU and to enable use of multiple PSUs
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have thick enough wires on +12v lines, so they won’t burn, but not thick enough to cause significant voltage drop
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all +12v lines shorted on the riser - to not overcurrent one pin only
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wires soldered directly to slot
5*) +5v/+3v lines also going to PSU --> “ideally”
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capacitors on +12vground, closer to load - better, HF fast capacitors, tantalum(?), solid(?), rating(?)
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ground line also soldered and connected to PSU
Ideal multi-PSU
- different PSUs +12v rails separated from each other
- different PSUs +5/+3 rails separated from each other
3*) same PSU rails not mixing with each other - Properly synced - aka turning on/off at the same time
* does not really matter or not in the scope of the subject
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[quote]6) capacitors on +12vground, closer to load - better, HF fast capacitors, tantalum(?), solid(?), rating(?)[/quote]
As for solid electrolytes, you want some radial ones probably. Nippon Chemi-Con PSC 270uF/16V (diameter 8mm) are a good choice. PSA or PS are older models with a little bit higher ESR. If you can get and fit Nippon PSC 470uF/16V (diameter 10mm), that’s even better. Sanyo solid electrolytes are more expensive usually unless you’re salvaging them from broken equipment.
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[quote name=“ghostlander” post=“47275” timestamp=“1387875839”]
[quote]6) capacitors on +12vground, closer to load - better, HF fast capacitors, tantalum(?), solid(?), rating(?)[/quote]As for solid electrolytes, you want some radial ones probably. Nippon Chemi-Con PSC 270uF/16V (diameter 8mm) are a good choice. PSA or PS are older models with a little bit higher ESR. If you can get and fit Nippon PSC 470uF/16V (diameter 10mm), that’s even better. Sanyo solid electrolytes are more expensive usually unless you’re salvaging them from broken equipment.
[/quote]Thanks, I have a batch of Sanyo OS-CON, will use them.
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[quote name=“wrapper0feather” post=“45855” timestamp=“1387380800”]
Any chance this could be compressed into one page, I’ll edit into the pinned guide in mining, if required?I found it confusing what was decided safe at the end. Possibly room for someone to do a Youtube / Blue Peter “video how to”.
I just use a riser, but I like to see steam punk solutions.
[/quote]
+1
Do this, this, this, end.
No opinions :) -
[url=http://www.kitguru.net/components/power-supplies/zardon/silverstone-strider-gold-1200w-psu-review-sst-st1200-g/2/]http://www.kitguru.net/components/power-supplies/zardon/silverstone-strider-gold-1200w-psu-review-sst-st1200-g/2/[/url]
[img]http://www.kitguru.net/wp-content/uploads/2011/06/cables.png[/img] -
nutnut, rep for the post as it saved me a bunch of$$ on risers and I believe will end me with a better quality rig.
Suggestion for the next info post would be wiring of dual PS on a 4 card rig.
Thanks again
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I’m curious do I still need to cut the cables to remove it from going back to the board. Because I plan on being able to have 7 AMD R9 280x GPU’s in one rig. 5 x PCI-E X16 powered riser and 2 x PCI-E X1 --> PCI-E X16 powered riser
Basically they are these ones [url=http://www.moddiy.com/products/PCI%252dExpress-PCI%252dE-1X-to-16X-Riser-Ribbon-Extender-Cable-w%7B47%7DMolex-%252b-Solid-Capacitor-%2830cm%29.html]http://www.moddiy.com/products/PCI%252dExpress-PCI%252dE-1X-to-16X-Riser-Ribbon-Extender-Cable-w{47}Molex-%252b-Solid-Capacitor-(30cm).html[/url] and their PCI-E X16 --> PCI-E X16 equivalent as well… Do I need to do any modifications to keep it from frying my board or no?
Also I have planned on two Silverstone Zeus 1,350 Watt PSUs for my rig how should I connect them all? Can I use one PSU for say the motherboard, HD, and such plus 3 GPU’s and their powered Risers and the other PSU to the other 4 GPU’s and their powered risers?
