United Chemi Con, good elco's or ? - Page 1
Forum section: electronics / projects

author: Kjelt
author_rank: Super Contributor
timestamp: July 02, 2016, 05:28:02 pm
content: Hi all,a friend of mine has broken elco's from Yageo in his amplifier and wants them replaced.They are 10000uF/80V snap mount type with 10mm between pins and casesize 35x50mm and a Ir=6AHe was advised to find Ir=8A or higher elco's so I searched what I could find from Rubycon, Nichicon and the sorts but to no prevail.So I finally found a SMH800VSN153MA80T from United Chemi-con with 15000 uF and a 35x80mm cansize and Ir=9A.My major concern is I know Nippon Chemi-con they were good quality japanese capacitors but what is the opinion about the SMH series from United Chemi-con?Thanks all

author: wraper
author_rank: Unknown
timestamp: July 02, 2016, 05:34:00 pm
content: United Chemi-con is North American subsidiary of Nippon Chemi-con, why should you have any concern about them?

author: Kjelt
author_rank: Super Contributor
timestamp: July 02, 2016, 05:41:46 pm
content: I don't know them, have no experience or opinion yet, so I would like an expert or (un)happy customers opinion before I help a friend from the the bad to worse.

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 02, 2016, 07:55:07 pm
content: Quote from: Kjelt on July 02, 2016, 05:41:46 pm*Genuine* United Chemi-Con capacitors are good quality. Get them from a reputable parts distributor like Farnell, DigiKey, etc., and you should be fine. Avoid ebay, in particular (almost as bad as alibaba when it comes to counterfeit goods).

author: Kjelt
author_rank: Super Contributor
timestamp: July 02, 2016, 11:46:28 pm
content: Also if the Ebay offer is from Europe?

author: wraper
author_rank: Unknown
timestamp: July 02, 2016, 11:59:27 pm
content: Quote from: Kjelt on July 02, 2016, 11:46:28 pmDepends, study the seller first. Assume nothing, seller might just got a pile of cheap crap from China regardless of location.

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 08:34:28 am
content: Will they measure the same on ESR or how can I tell (measure) if they are genuine or fake?

author: jitter
author_rank: Frequent Contributor
timestamp: July 03, 2016, 08:34:40 am
content: Quote from: Kjelt on July 02, 2016, 11:46:28 pmOn eBay you run amuchhigher risk to receive counterfeits than through authorized dealers. Next best bet are reputable dealers.A list of authorized dealers should be found on the manufacturer's website. Often those will be big boys selling only wholesale to the industry (Arrow, Avent to name a few). For low volume I would suggest you look at the likes of Mouser, they will also sell single/low volume stuff to consumers. Farnell may only do so if a minimum order value is reached.United Chemicon uses the same logo as Nippon Chemicon and you will find that factory mentioned on the Nippon Chemicon website. I would expect quality to be on par.

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 08:37:58 am
content: I did check the regular endsellers like farnell, mouser and the likes, they did not have them in stock and only sell with 400 piecesThe biggest problem is the max can diameter of 35 mm that will fit the pcb product else there would have been numerous of other possibilities.

author: jitter
author_rank: Frequent Contributor
timestamp: July 03, 2016, 08:38:36 am
content: Quote from: Kjelt on July 03, 2016, 08:34:28 amDepends what they use. If you're lucky, it will measure outside specs straight away. And apparently the vents pressed in the top of the cap may give away a counterfeit visually.On a decent (but counterfeit) cap capacity and ESR/Dissipation factor might be similar enough to start with, but you don't know how they will hold their value in a couple of years' time.I can only add that if the price looks too good to be true, it usually is.

author: jitter
author_rank: Frequent Contributor
timestamp: July 03, 2016, 08:42:57 am
content: Quote from: Kjelt on July 03, 2016, 08:37:58 amHere's afiltered listof what Mouser have to offer in 10,000 uF (= 0.01 F)/80 V and 35 mm diameter and 10 mm lead spacing. There are a couple with an MOQ of 1.The only criterium I see is not met is the Ir of 8 A, but perhaps 6.63 A is close enough?

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 08:43:18 am
content: The price is much higher than the 400 pcs price of mouser (about one and half times higher) which is to be expected.Thanks all for the replies At least the consensus is that United Chemi-con are decent/good capacitors.

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 08:45:36 am
content: Quote from: jitter on July 03, 2016, 08:42:57 amNo they really want 8A that is why my suggestion was to go to the 15000uF 35x80mm packageThe original elcos lasted 6 years, these will last way longer due to the larger Ir and size of the package.

author: jitter
author_rank: Frequent Contributor
timestamp: July 03, 2016, 08:53:27 am
content: What amp are we talking about?Going higher in capacitance may lead to problems like higher peak currents drawn from the transformer. I once actually lowered a DIY headphone amps' PSU smoothing capacitance because the scope showed the transformer didn't like the peak currents drawn at the peaks of the sinus to top up the smoothing caps. Lowering the capacitance resolved that issue.Going 50% above the original may not be a problem, but maybe someone else can chime in on this?

author: wraper
author_rank: Unknown
timestamp: July 03, 2016, 09:08:20 am
content: If you replace Yageo with some Japanese cap, it will already last significantly longer than original one, even with the same ripple current rating. On the other hand, "japanese" caps from ebay may fail in a few months. Also you can try searching CDE or BC caps at reputable distributors instead.

author: jitter
author_rank: Frequent Contributor
timestamp: July 03, 2016, 09:15:16 am
content: BC is owned by Vishay, so you may have to search for BC/Vishay or Vishay instead. Yes, they are good quality too, a well known and trusted brand in industrial electronics. I would have no problems substituting any brand of cap (even the big Japanese brands) with these, although I doubt they will be any cheaper.

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 03, 2016, 10:09:26 am
content: I wouldn't know if ebay sellers are more honest in Europe than in the US, but I doubt there is much difference, especially if the seller is in China! Seriously, the percentage of electronic parts that are counterfeit on ebay is incredible: easily 90% or more for any seller in Asia (including Philipines, Malaysia, Singapore, etc.).Now when I filter on elkos at digikey with the same general specs as the UCC part number you gave earlier I come up with -0- that meet all criteria. That suggests rather strongly that one or more specs need to change. I would double check the lead spacing, because 10mm is awfully close for a 35x80 can.

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 11:27:04 am
content: Yes i look at all those caps manufacturers I know are good but they only had the same Ir of 6,3A except one from Rubycon that had 7A in the same 35x50 can however it was unobtanium from the major sellers unless you order a 100I was somewhat dissapointed since i thought that if Yagei could have the elcos with these specs back in 2005 the a brands would by now have something smaller or better specs. It seems that elco development has come a bit to a stop with these larger ones.My friend is going to an electronic shop tomorrow to see if they have something in stock else we will probably order or the same version from an A brand or the Ebay ones from ucc to see how they measure.

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 03, 2016, 02:01:04 pm
content: You seem to be really fixated on getting 9A of ripple current, but it is possible you don't need that much. What was the part number of the cap that was originally installed and what are the specs of the amplifier (need to know the continuous power and speaker impedance at a minimum)?

author: Kjelt
author_rank: Super Contributor
timestamp: July 03, 2016, 04:38:26 pm
content: It is aHypex DS4.0, so 400W at 4ohms.The original parts were two Yageo LH series elcos, 10000uF/80V 35x50mm.He gets two new replacements sent from the manufacturer, they claim it was probably a bad batch and told him to go for Ir>=8Amps which is peculiar since those Yageo's only are rated for 6,3Amps.

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 03, 2016, 07:19:20 pm
content: Quote from: Kjelt on July 03, 2016, 04:38:26 pmHmm... It's a class-D amp, which complicates things. You said there are (2) of them in the amplifier? Are there any other large electrolytic capacitors inside? Were you able to measure the voltage of the power supply rail(s) - note that it is possible to make a Class-D amplifier with a unipolar power supply, but then you need to provide an AC ground that is midpoint between the positive rail and DC ground, and the usual way of doing that is with 2 large elkos in series. Smaller elkos could be used for bulk filtering of the power supply rail(s), esp. if a switchmode power supply is used, but there's no way around using large value elkos for the AC midpoint as you need to minimize voltage imbalance all the way down to 20Hz (or lower).