Corporate propaganda to justify cheap Chinese caps - Page 1
Forum section: electronics / general

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 12:59:10 am
content: Corsair (PC PSU manufacturer) got some flak recently for putting cheap capacitors (Ltec and CapXon) in some of their newer high-end power supplies (RM and CSM series). This questionable choice in components was compounded by the designs having very cramped PCB layouts (750W and 850W models basically have the filter capacitors in an airless box), and having low-RPM fans that don't turn on until the PSU exceeds 60% load, or the secondary heatsink exceeds ~100*C.http://www.corsair.com/blog/capacitor/They're using the life expectancy formula and the specs provided in Ltec's datasheet to claim a 15 year lifetime for their secondary capacitors.

author: Fsck
author_rank: Super Contributor
timestamp: January 29, 2014, 01:07:10 am
content: it's marketing. enough truth so that most people will accept it as the complete truth since they probably don't know better.addendum: someone should challenge them to back up their 15-year life with a 15-year warranty.

author: bridgerectifier
author_rank: Contributor
timestamp: January 29, 2014, 01:14:48 am
content: My friend has run a PC shop for years, and he told me a few years ago that quite a number of a certain Corsair "high-end" PSUs have gone bad - I have one of his cast-offs here with me - kept for heatsinks and inductorsJUNK! Living off a name, earned by gamers who are marketed into thinking Corsair are "the best". LolI always like to know what COMPONENTS are inside the parts that computer engineers call "components" - IE, a PSU is referred to as a "component", as is RAM etc, but these "components" are comprised of many circuit-level components, which can be crap, but these PC people often (not always) know no better.I know the above sounds obvious... just had to get it out

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 01:34:06 am
content: Quote from: Fsck on January 29, 2014, 01:07:10 amThey claim a 5 year warranty. I'd give those caps a half life of 3-4 years. Hopefully it comes back to bite them.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 29, 2014, 01:40:00 am
content: Yet another case of the not-so-smart fan. It degrades reliability and adds another marketing feature. A double win for them, a loss for us.I suggest buying server grade PSUs if you really need the reliability, but those don't come cheap.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 01:52:10 am
content: You can get reliability in the consumer market. You just have to pay for it, and do your research.

author: all_repair
author_rank: Frequent Contributor
timestamp: January 29, 2014, 02:18:54 am
content: At the back of their mind is: effective warranty is 12month (after that people that claim are far in between even stated as 5 year), life of product is 24month, and next product launch is 18 month that has a 2x speed, 2x memory, 200x more features.So the capacitors are over spec.

author: echen1024
author_rank: Super Contributor
timestamp: January 29, 2014, 02:25:07 am
content: I use a Corsair 650W. I'll open it up sometime, maybe take some pics.

author: Vgkid
author_rank: Super Contributor
timestamp: January 29, 2014, 06:57:51 am
content: JG would not be happy about this.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 07:18:46 am
content: Quote from: Vgkid on January 29, 2014, 06:57:51 amJohn Gerow (the founder) works for Corsair as a consultant now and is desperately arguing with anyone who points out the absurdity of believing CapXon and Ltec datasheets.Jeremy Schrag (the current main reviewer) deducted a point for it, but otherwise didn't call them out on it much.

author: AndyC_772
author_rank: Super Contributor
timestamp: January 29, 2014, 07:23:42 am
content: Quote from: wilfred on January 29, 2014, 02:31:28 amStart with the rated basic lifetime of the capacitor, and apply a formula to adjust this figure based on the actual operating temperature in service. The theory presented in the blog is sound.It's also important to take into account what constitutes 'failure', because it's not nearly as well defined a some people think. What happens is that over time, the properties of the capacitor simply degrade; the capacitance goes down, and at some point it's no longer within the spec in the data sheet. At this point it's deemed to have 'failed', even though the circuit may continue to operate perfectly well for years to come.This gradual degradation (as opposed to 'sudden death') is one reason why most products that use electrolytic caps do actually last way longer than the rated lifetime of the parts from which it's built. If every cap that had, say, a 3000 hour lifetime rating actually did fail completely and become useless after 3000 hours, we wouldn't be complaining about the odd PSU that fails under warranty - we'd be replacing them routinely like batteries.Of course, some caps do fail catastrophically, but they're the statistical outliers... the ones that most likely had latent defects from day one, and were never going to meet the data sheet specs for reliability. Some manufacturers may indeed have better QC than others, and gain a reputation for 'good' or 'bad' quality accordingly, but that doesn't mean the way to calculate a capacitor's lifetime is flawed.Normally when I design a product using electrolytic caps - say, a PSU output filter - I'll start with a reasonable estimate of how hot I think it's going to get in service, and then design in enough capacitance such that even if the parts do degrade over time, there will still be enough for the product to work correctly once the design lifetime of the product has expired. Then, once a prototype has been made, I'll hook up some thermocouples and check the actual temperature of the capacitor in service, to make sure that MTBF estimate was accurate.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 07:24:42 am
content: Quote from: wilfred on January 29, 2014, 02:31:28 amSeveral problems,1. This is an idealized formula that doesn't take into account impurities, build defects, and other issues with the capacitor.2. Environmental factors such as changes in temperature, humidity, and pressure, length of storage, and treatment during soldering will effect the lifetime of the cap.3. It uses an average ripple current figure and doesn't take into account transient events that will inevitably occur due to rapid load changes or input surges.4. Chinese capacitor manufacturers regularly lie or inflate the ratings of their components, so plugging their numbers into the formula is a rookie trap.5. Even if everything else is accounted for, this is at best a rough mean. It doesn't give any useful statistical information, and when you make tens of thousands of power supplies with dozens of caps each, you have to look at the worst case in the second or third standard deviation, as a 0.1% capacitor failure rate can still equate to hundreds of unit failures in the field.The lame excuse that John Gerow and George Makris (Corsair reps) give is that every other power supply in the last 20 years that has failed due to using Ltec, CapXon, or other off-brand caps must have been designed by an idiot with too high of a ripple current. Additionally they try to smear Japanese caps by pointing out that some are now made in Malaysia, while admitting quietly that the reason Japanese caps are better isextra margin,better materials, andQC. None of which is affected much by the location of manufacture. And while Chinese manufacturers may be getting access to higher quality aluminum (in a year or two, not now...) and electrolytes, the majority are still way behind on QC, and they do not provide the safety margin that Japanese manufacturers do, which is a large part of what gives them their legendary reliability.

author: XOIIO
author_rank: Super Contributor
timestamp: January 29, 2014, 07:26:42 am
content: I think I'll stick with cooler master or.. hrmm, there's another brand but I can't place my finger on the name right this second.Oh well. I've always thought corsair had a bit too much hype around it.

author: peter.mitchell
author_rank: Super Contributor
timestamp: January 29, 2014, 07:33:52 am
content: Quote from: NiHaoMike on January 29, 2014, 01:40:00 amIf you don't mind modifying some connectors and the load noise of fans, they aren't THAT expensive...Quote from: wilfred on January 29, 2014, 02:31:28 amI'd say there is a pyramid of reasons, starting at the unreliability of these manufacturers. These companies fudge the numbers on the datasheet a little bit at the best of times, let alone the quality control.Next up would be them using near best case numbers for the basis of their calculations, eg;QuoteNot a snowflakes chance in hell they would be running at those temps in a standard computer case, i mean, Wilfred, its 43 degrees ambient here today for crying out loud!Then you have to take into consideration things like was the wave soldering profile to spec, how long were they in storage, how well is the ripple current balanced between the caps in the design, how do they age, how do they handle thermal cycling?

author: tszaboo
author_rank: Super Contributor
timestamp: January 29, 2014, 07:53:25 am
content: Chinese manufacturer said it in the datasheet.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 08:04:01 am
content: Quote from: peter.mitchell on January 29, 2014, 07:33:52 amThey use even cheaper capacitors in their Australian (APAC region) units than they do in their US ones. This is evidenced by the Corsair unit Dave opened when he was upgrading his PC. It used lower tier capacitors than the ones used in the same SKU in the US. And of course US spec units are the ones that go to reviewers. They forget that ozzies also have screwdrivers and soldering irons.

author: peter.mitchell
author_rank: Super Contributor
timestamp: January 29, 2014, 02:04:22 pm
content: QuoteEven if they did, if you design around average rather than minimum it will bite your ass.QuoteNo, if you place the caps against heatsinks, away from vent holes, behind components blocking airflow ect, the average temperature may swing from ambient +5 degrees at full idle to ambient +80 degrees full load.Since you're a massive manufacturer you can afford different units for different locales, if you're sending it to a humid locale, use more humidity resistant parts.Treatment during soldering is easy, you're the manufacturer, you can choose exactly that.Same with length of storage, buy minimal over-stock and buy new lots for new batches.QuoteTransients are transients, they're hard to appropriately estimate, however, you can always calculate for expected worst case + margin, rather than calculating to the mean.QuoteSure you would, and the company would go "hey, were making shit tonnes for money and people aren't complainingmuch, lets just keep doing it" - doesn't make it good for the consumer though.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 05:14:29 pm
content: QuoteActually you can't really. Not unless you're as massive as, say, Delta Electronics. The same batch of power supplies, divided between distributors in the US, may end up in climates as diverse as Malibu, Denver, Miami, and Minneapolis. Though I would consider it ideal for PSUs sold in the APAC region (usually includes southeast Asia and Australia, occasionally India or East Asia) to have higher-spec caps to account for the heat in this region, the fact that most of the countries in that area are poorer means that most companies cut cost by using cheaper caps.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 29, 2014, 09:22:08 pm
content: Quote from: Phaedrus on January 29, 2014, 05:14:29 pmGet rid of the "smart fan" and it will run cooler. Of course, that would make the unit too reliable for future sales...A trick you can do (if you're not willing to spend the extra for a server grade unit) is to pressurize the case with a powerful fan.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 11:58:14 pm
content: Assuming that capacitor failures approximate a bell curve, designing for the average +/-1 standard deviation will give you a 15% failure rate. Obviously not a good plan.We target a failure rate <0.5% over the warranty lifetime of the product. A product that gets more than 1% failure rate is considered troublesome, and more than 2.5% is considered awful--this is what we get for the cheap non-80PLUS PSUs we used to sell before we realized warranty replacement costs exceed our sales margin... The worst products we've ever sold only hit about 10% failure rate and are considered abject failures.Anyway, you want to target a few standard deviations below the average if you want your product to be at all reliable. Then you have to figure that that lifetime calculation is per cap, not per unit... It adds up. Add in the inflated specs in Chinese data sheets, unforeseeable transient events, base manufacturing error rate, storage and environmental degradation, potential partial failure of other components, and a host of other issues.You can use cheap capacitors in your products. You can't claim that they are as reliable, or even nearly as reliable, as their Japanese and upper-end Taiwanese equivalents.

author: iampoor
author_rank: Frequent Contributor
timestamp: January 30, 2014, 09:25:38 am
content: Quote from: Phaedrus on January 29, 2014, 11:58:14 pmHey PhaedrusNot to hiajk this thread, but were you one of the stuff at overclock.net who did all the PSU reviews?

author: poorchava
author_rank: Super Contributor
timestamp: January 30, 2014, 11:24:24 am
content: One word: Seasonic.(performance+lifetime)/price approaches infinity. Look for teardowns of those: you won't find any capacitor brand other than Chemicon, Rubycon, Panasonic, Nichicon. Brand name parts, even fans are SanyoDenki.Actually, I think all of the Corsair and Antec PSUs from "higher" end are also made by Seasonic

author: TMM
author_rank: Frequent Contributor
timestamp: January 30, 2014, 11:53:00 am
content: Quote from: poorchava on January 30, 2014, 11:24:24 amUsed to be, now they just seem to go with whatever OEM is the cheapest at the time.http://whirlpool.net.au/wiki/psu_manufacturersDelta is reasonable. FSP is 'okay', don't expect them to last 5+ years. I dunno what CWT are like these days. They made the Antec TruePower(1) series which was popular around release but after about 5 years they all failed from bad caps.FWIW i have had a Seasonic fail and take some harddrives with it but still regard them as generally well built supplies.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 30, 2014, 05:24:50 pm
content: Quote from: iampoor on January 30, 2014, 09:25:38 amYes

author: VK3DRB
author_rank: Super Contributor
timestamp: January 31, 2014, 09:05:36 am
content: You close your electronics factories, sack your neighbours, lose your skills and get your stuff made in a third world country like China. Don't expect good quality. Or sympathy.

author: ConKbot
author_rank: Super Contributor
timestamp: February 01, 2014, 04:52:08 am
content: Quote from: mojo-chan on January 30, 2014, 01:37:01 pmhttp://www.hardwaresecrets.com/page/powermost people dont have the ability to properly test or evaluate a PSU. Hardware secrets load tests it, records noise (electrical) under load and unloaded etc... Then tear it to bits and comment on the internal construction. Definitely a goto resource imo. They dont paint it as colorfully as some, mainly just presenting the facts and making a factual conclusion.http://www.hardwaresecrets.com/article/TiVECO-TVPS450-Power-Supply-Review/1436them tearing down a $20 cheapiehttp://www.hardwaresecrets.com/article/PC-Power-and-Cooling-Silencer-Mk-III-750-W-Power-Supply-Review/1722/12and one of a decent quality.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: February 01, 2014, 05:52:23 am
content: The top reviewers used to be:Gabriel Torres(PSU reviewer atHardwareSecrets.com) is retiredJohn Gerow(founder ofJonnyGURU.com) works for Corsair on retainerPaul Johnson(PSU reviewer atHardOCP.com) has a lot of enemies in the industry, so doesn't get many review samplesBut not they don't generate many reviews.Currently it's:Jeremy Schrag, current reviewer atJonnyGURU.comcrmaris(forget his real name), reviewer atTechPowerUp.comandTheLab.gr(he's in Greece)They're the most thorough and competent reviewers. Paul Johnson is good as well, but he's abrasive and very hard on the companies he reviews, so he has a lot of enemies and has to buy most of his own samples (which he can't afford many of). We've restarted our relationship with him though. I like him. He's just a bit blunt. And people said that *I* was blunt, so take that into consideration...

author: BravoV
author_rank: Super Contributor
timestamp: February 01, 2014, 06:19:18 am
content: Since the OP works for Cooler Master cmiiw, while this thread is bashing at Corsair (competitor), just curious if anyone smell "a bit" of marketing campaign here ?PS, never owned Corsair nor affiliated with it, all my PSUs are Seasonic.

author: mariush
author_rank: Super Contributor
timestamp: February 01, 2014, 06:49:07 am
content: Not sure how much it matters (since you don't know me) but Phaedrus never seemed to me as a person bashing competitors. I've read his posts on Jonnyguru and other forums and he never seemed to me like promoting his employer excessively or bashing competitors on purpose, just expressing his views.I really think "doing marketing campaign here" is a far fetched idea.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: February 02, 2014, 06:50:29 am
content: Not marketing, just bitching. If I wanted to market against Corsair I'd do it on a more computer enthusiast-centric website where it would have orders of magnitude more impact. And I still wouldn't do it because it would most likely have backlash.Just pissed at people getting lied to, and Corsair making money off it. I've heard Corsair compared to HP lately; after they divested Agilent and went full greed mode, that is.