Don’t order parts on eBay, I’m convinced they’re all counterfeit. You can see the dies on these supposedly genuine transistors aren’t even 1/4th the size of the originals, and though the amplifier seemed to work OK they blew and torched a receiver I repaired at only modest volume levels. So learn from my mistakes, even if you don’t think it matters, it really does- even at low power levels.
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In other news: The bear still defecates in the woods. 
B+D Enterprises is my go-to for obscure/obsolete parts. Anything in current production I buy through Mouser/Digikey/Newark/Future/etc.
Tom
B+D Enterprises is my go-to for obscure/obsolete parts. Anything in current production I buy through Mouser/Digikey/Newark/Future/etc.
Tom
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LOL
Mostly you gotta avoid China, 99% of the fakes originated there, and if you are careful you can avoid the folk outside China who are re-selling the junk they got from China in the first place.
When you account for your time, and you only live once, just buy from a reputable source. If you can’t afford to do that, scrounge it from old e-waste or choose a different design - there are many roads to good sound (don’t get lost in the hype).
I bought some irfp240/9240 from China.
The amp powered up fine.
So job finished I unplugged my soldering iron and the glitch down the mains blew the amp up.
So I decided to buy next batch from RS to see how long they lasted.
Been going a year now.
Clearly fake parts had very low breakdown voltage.
The only thing I now buy from China (knowingly) is pcb's.
The amp powered up fine.
So job finished I unplugged my soldering iron and the glitch down the mains blew the amp up.
So I decided to buy next batch from RS to see how long they lasted.
Been going a year now.
Clearly fake parts had very low breakdown voltage.
The only thing I now buy from China (knowingly) is pcb's.
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Joined 2009
Paid Member
the way I see it, there are more interesting things I can build than my lifespan will allow so why give myself any grief from dodgy parts
Sure, some old classic electronics can be kept going a little longer if you can find the real thing, but, everything has it’s day and at some point you either move on to a different solution or else roll up your sleeves and design a patch using modern materials that you know are good
Really, it’s just is not worth your limited time and energy - too many alternatives for your enjoyment if you can avoid getting stuck on the one solution because of some influencers who have only their own interests at heart...
Sure, some old classic electronics can be kept going a little longer if you can find the real thing, but, everything has it’s day and at some point you either move on to a different solution or else roll up your sleeves and design a patch using modern materials that you know are good
Really, it’s just is not worth your limited time and energy - too many alternatives for your enjoyment if you can avoid getting stuck on the one solution because of some influencers who have only their own interests at heart...
Whenever I buy from China, I always make a test purchase first.
These are then cut open to check the die size.
All the photos are of " 2N3773s."
2 were bought from China and one from the UK.
I'll leave it for you to decide which is which.
Andy
.
These are then cut open to check the die size.
All the photos are of " 2N3773s."
2 were bought from China and one from the UK.
I'll leave it for you to decide which is which.
Andy
.
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Someone told me about a large medical company that used the TO-3 7805 style regulator. Well the bean counters didn't like what that part cost from legit suppliers so they went on eBay and found them much cheaper. Well you can probably guess the fake parts had the same size die as the TO-220 style.
They did use different size die in the 7805 and 78M05 both in TO-220. The latter was only rated half an amp. The TO-3 and the ones without the M used the same die. Then there was an even smaller L die for the TO-92. The 3 die sizes had specific current limiting for the size. God only knows what may be in a truly fake die - or if it even had current/thermal limiting at all.
I wont name and shame but on ebay but there is a semiconductor seller that charges full whack for fakes. I bought some iRFB4227's off him and they didnt last 5 minutes. Got some genuine ones and they worked great.
The only way to be certain with fakes is to buy from reputable vendors like RS, Farnell, Digikey, Mouser etc.
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