Impossible Ebay Item - Or not?

benb

Member
2010-04-24 1:52 am
okay so i found this item on ebay... it looks like what i need for building a small amp

6*10000uF/80V high quality power supply board for amp - eBay (item 120617370427 end time Nov-03-10 02:45:27 PDT)


the problem is that i looked up the prices for those capacitors: around $8.00 each. six of them would mean that the board should cost upwards of $50.00, yet it's on ebay, including the pcb and several other components for $32.00 plus $16.00 shipping.

is this a clear fake?
The seller says it's new (actually the full "Item Specifics" looks like a general blurb for all the seller's parts), but it could be a surplus board, "new" as in unused, manufactured to be an assembly in some product, but for whatever reason - sales fell, product design change, the maker went out of business - the were surplussed by the maker and the seller got them. I've seen a large amount of electronic parts, at least from US eBay sellers, that fall into this category, though admittedly they're in original packing and not assembled onto boards. Authorized parts distributors have strict return policies to keep from receiving fraudulent components as returns (though I understand these policies may not always work). Clearly products soldered to a board can't be returned to a distributor. As a result, these components can only be sold on the surplus market, where buyers are likely to be as suspicious as the OP, and the attraction is the reduced price over the same quantity from a distributor. The seller/surplusser at least gets SOME amount of money for these parts rather than storing or trashing them.

So, yes, it could be fake, but could reasonably be perfectly good products at a discount price.
Chinese electrolytics are notoriously bad quality so you get what you pay for
There's certainly been problems with electrolytics from China, and it lasted many years, as this thread discusses;
http://www.diyaudio.com/forums/everything-else/169516-tale-bad-capacitors-taking-company-down.html
From what understand by reading news stories on the problem (linked to in that thread), people stopped seeing this particular problem (the infamous bad electrolyte formula) in parts manufactured around 2007 and since.

So there's no guarantee that capacitors from China (or any product from anywhere through eBay, especially when you order internationally) are good, but it appears that specific "capacitor problem" no longer exists.
 

stigs

Member
2010-06-25 6:00 am
As benb stated it's probably for real. However you get what you pay for. I just purchased a supply from Cristi at Connexeltronic and it works great. Take a look at his PS10K100 and for not much more money it uses 100v caps and it is fused too. When ordering from China be sure to check shipping options because with standard shipping mine arrived after 28 days. UPS or DHL would quicker and is insured.
 

ncc

Member
2006-07-16 9:26 am
VN
printing that rubs off with alcohol are goods indicators.

That's a good way to test for a fake capacitor.
I've seen fake Dale resistor and fake Jensen PIO Capacitor made in China, they're so well made that most of us can't tell they're fake.

My friend accidentally purchased and used some of the fake dale resistors in his tube preamp together with some original ones, after a year under the hot environment inside the preamp case, the brown color of the fake ones starting to fade considerably while the color of the original ones stayed the same.
 

ThorstenL

Previously: Kuei Yang Wang
Hi,

okay so i found this item on ebay... it looks like what i need for building a small amp

6*10000uF/80V high quality power supply board for amp - eBay (item 120617370427 end time Nov-03-10 02:45:27 PDT)

the problem is that i looked up the prices for those capacitors: around $8.00 each. six of them would mean that the board should cost upwards of $50.00, yet it's on ebay, including the pcb and several other components for $32.00 plus $16.00 shipping.

is this a clear fake?

Well, the circuit board picture shows (real) Nichicon Capacitors.

The text says Rubycon.

Rubycon Cap's are frequent in China and non I have had the chance to see where Rubicon, but all where Fubicon (Fake Rubycon). I have also seen the rarer Fichicon Cap's.

If you sufficiently overrate these Fubicon's (e.g. de-rate ripple current and working Voltage by at least 30% compared to the originals) they usually hold up well, even though they measure worse than the originals they will be serviceable.

You can buy the 10,000uF/63...80V Fubycon Cap's in the electronics markets in China for the equivalent of 1 USD or less (especially if poor quality) each. The Diodes and Heat-sinks come in at another less than a dollar each. The PCB in small quantities and in super quality will cost at best 2 USD, if the PCB is poor quality (thin PCB, thin Copper etc.) it may be as little as 50 Cents.

I doubt the print on the capacitors will be as crisp as on the pictures etc. so your call.

I personally would probably instead buy genuine Elna Silmic of lower value from a reputable seller and spend a bit more and hardwire. Actually I not only would, I did...

My Chipamp with 4 pcs of 3,300uF Elna Silmic II Power Supply Capacitors

These cap's have measurably (in a whole amplifier) lower distortion than ten times the value in conventional "branded" electrolytic capacitors and probably around thirty times the value of Fubicon and Fichicon, which makes them actually a bloody bargain, despite being quite expensive per uF...

And solid silver wire does make a much better conductor than electrolysis deposited copper.

Then again, that's just me. As said, if you don't exceed around 50V working voltage and maybe 10A Ripple current the board from e-bay should work well enough.

Ciao T