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| adding capacitors to a PC power supplies output [ project ] |
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| forestelf:
hi, im forestelf im new here and i wanted to throw a question out to knowledgeable ppls ~ ! for some background= i own a EVGA 750W GQ semimoduar computer power supply and it has ripple level of about ~60mv on the 12v rail, and i was reading a review over at toms hardware https://www.tomshardware.com/reviews/evga-gq-series-750w-psu,4396-3.html and over on the front of the powersupplys' pcb (where the cables connect into, there is a some places designed to have additional capacitors soldered to them, but they were left empty,(presumably a cost related decision) and in the tomshardware review, they mention "At the front side of the modular PCB is free space for installing additional filtering caps, though EVGA apparently decided it didn't need them. That's a shame, since this platform doesn't have good ripple suppression." (according to their tests) so i had an idea to reach out to more knowledgeable ppl than myself about this, about whether this is something beneficial to do, or if its even possible~ (i have soldering skills but not a massive knowledge of pcb electronic circutry) theres alot of photos up on the tomshardware review, lots of info too, &if theres anything youd need to know that i can help with, please ask :) i guess the main questions are; is it possible and is it beneficial(even if only a little bit); but more importantly where would i find out which capacitor would be best for the job and would the existing circutry allow for these capacitors to simply be added on their own? any help is much appreciated, thanks for droppin by my post :D <3 |
| mariush:
There's extremely small benefit to adding capacitors on the output, and 60mV is well within the acceptable range (up to 120mV for 12v I think). Adding a bit of capacitance by the connectors may help a few more Mhz when you're overclocking video cards but that's about it. Keep in mind that you have capacitors in the power supply and there's capacitors on the video card or motherboard as well, so you basically have C-L-C , because the wires have some inductance. Whatever you add on the power supply would not make a huge amount of difference. I don't know, if you want to add them... aim for polymer capacitors, anything in the 270-470uF 16v would be suitable. |
| Gyro:
Welcome to the forum. Personally, I would leave well alone. With so many heavy wires coming out of the PCB, there is far too much chance of bending the existing caps over and damaging their seals, shortening their life. Adding extra caps might reduce ripple slightly, but they would need to be the same low impedance ones as the existing ones to share current properly. The manufacturer has put in as many as are needed to meet spec. Adding more (apart from the possible mechanical damage I mentioned above), could well reduce their life more by blocking airflow and increasing temperature, by more than they save. Is it just me, or do PC PSUs get messier the more advanced they get? I've never seen so many wires coming out of a PSU PCB. :o |
| WildMOSFET:
--- Quote from: Gyro on March 14, 2019, 05:29:20 pm ---Welcome to the forum. Personally, I would leave well alone. With so many heavy wires coming out of the PCB, there is far too much chance of bending the existing caps over and damaging their seals, shortening their life. Adding extra caps might reduce ripple slightly, but they would need to be the same low impedance ones as the existing ones to share current properly. The manufacturer has put in as many as are needed to meet spec. Adding more (apart from the possible mechanical damage I mentioned above), could well reduce their life more by blocking airflow and increasing temperature, by more than they save. Is it just me, or do PC PSUs get messier the more advanced they get? I've never seen so many wires coming out of a PSU PCB. :o --- End quote --- I agree in everything. If the manufacturer has decided not to put them, they probably aren't necessary. And we're talking about EVGA not some scrapped producer. |
| forestelf:
--- Quote from: mariush on March 14, 2019, 05:28:04 pm ---There's extremely small benefit to adding capacitors on the output, and 60mV is well within the acceptable range (up to 120mV for 12v I think). Adding a bit of capacitance by the connectors may help a few more Mhz when you're overclocking video cards but that's about it. Keep in mind that you have capacitors in the power supply and there's capacitors on the video card or motherboard as well, so you basically have C-L-C , because the wires have some inductance. Whatever you add on the power supply would not make a huge amount of difference. I don't know, if you want to add them... aim for polymer capacitors, anything in the 270-470uF 16v would be suitable. --- End quote --- hi thank you for the info! i compared some other psu capacitors and they were in that range,(not sure the difference in the colors and brands and whatnot, but im attaching a few photos as example of whats typically found on psu, on this psu-teardown page about half way down theres photos and description of all capacitors that are in this psu,(there japanese aparently) ( https://www.tomshardware.com/reviews/evga-gq-series-750w-psu,4396-3.html )(also added some of those pics onto this post) with this in mind, can you recomend one on ebay for me ? the price isnt important i can do the bargain hunting, itd just be for a closer reference! im seeking those small benefits so everybit counts,(even small overclocking benefits and prolonging motherboard components lifespan) i understand 60mv is acceptable, but if theres a performance gain to be had why not go for it? im wanting to smooth the ripple closest to the source and i think this is the simplest place (happens to even be designed for it) --- Quote from: Gyro on March 14, 2019, 05:29:20 pm ---Welcome to the forum. Personally, I would leave well alone. With so many heavy wires coming out of the PCB, there is far too much chance of bending the existing caps over and damaging their seals, shortening their life. Adding extra caps might reduce ripple slightly, but they would need to be the same low impedance ones as the existing ones to share current properly. The manufacturer has put in as many as are needed to meet spec. Adding more (apart from the possible mechanical damage I mentioned above), could well reduce their life more by blocking airflow and increasing temperature, by more than they save. Is it just me, or do PC PSUs get messier the more advanced they get? I've never seen so many wires coming out of a PSU PCB. :o --- End quote --- the place these capacitors are located have perfect clearance, no extra wires are in the way, all the higher end models have them in this place and similar pcbs use them as well, the slight benefit is the goal here, im not expecting the psu to transform into the best power supply of all time or anything lolol but the case allows ample room to secure a fit without modification. --- Quote from: WildMOSFET on March 15, 2019, 08:53:27 pm --- --- Quote from: Gyro on March 14, 2019, 05:29:20 pm ---Welcome to the forum. Personally, I would leave well alone. With so many heavy wires coming out of the PCB, there is far too much chance of bending the existing caps over and damaging their seals, shortening their life. Adding extra caps might reduce ripple slightly, but they would need to be the same low impedance ones as the existing ones to share current properly. The manufacturer has put in as many as are needed to meet spec. Adding more (apart from the possible mechanical damage I mentioned above), could well reduce their life more by blocking airflow and increasing temperature, by more than they save. Is it just me, or do PC PSUs get messier the more advanced they get? I've never seen so many wires coming out of a PSU PCB. :o --- End quote --- I agree in everything. If the manufacturer has decided not to put them, they probably aren't necessary. And we're talking about EVGA not some scrapped producer. --- End quote --- jus feel like if theres room for improvement i should do it. its not a high price unit or anything.(so it was perhaps an afterthought on evgas' side for reducing its cost/performance ratio as all similar models have these caps in those places its just this is not the top of the line version for the evga-GQ models) for me a couple japanese caps would presumably be a few dollars or so on ebay and is reasonable, i get that for a manufacturer catering to the budget psu consumer, that leaving out these caps on millions of units saves them alot of monies on their production and still results ina competitive unit for similar psus, but being the pcb wasent changed it leaves designated room for the caps with no physical modification to the unit being necessary so it seems like a great project right i get it could be a hassle for many people to go through this for such a small gain, but if im willing to, and for the small benefits/ if i could find a reccomendation for a particular capacitor on ebay id really like to go for it c:! ( first 3 photos show this 750w psus capacitor types on the main board last 3 photos show various modular psu pcb with typical cap location,) |
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