Fake Audio Amp IC?

Colin

One of them is new and is going to be fitted in the speaker. The customer does still have the original failed device but I don't have it back yet.

I wanted to take a photo before destroying the casing or I would not have been able to post this thread for external visual i.d..

Gareth.

Here's a hi res picture of the opened module:

What are those things?

Gareth.

My guess? A transistor die (unpackaged) There's 4 of them, each pair shares a 3-legged SMT.

Jeff

"Gareth the Menace" ...

** Here is the datasheet for the similar STK422-90.

The 4 output devices are Darlington pairs and the SMD devices in the middle of each pair are the bias stabilisers. The Darlingtons each have twin emitter leads soldered to the PCB.

Looks an easy enough to copy the thing - just normal SMD board plus four power chips on metal headers.

Older versions (made by Sanyo) had no SMD - but instead used transistor chips and printed resistors directly on the board. They were known as "hybrids" to distinguish them from regular ICs.

My local supplier ( WES Components) has the STK442-130 listed for A$22.50 each.

Littlediode in Surry offer them for 10 UK pounds + VAT.

.... Phil

"Gareth the Menace "

** It is rare for anyone to set out to manufacture a "fake" electronic device for sale - so the terms "fake" and "counterfeit" are misleading.

What IS done is to remove the labelling from a cheap device and re-label it as another, more expensive and far more sellable type.

In the case of the STK422 series of modules, the game would be to re-label a lower spec part as a higher spec one.

FFS - buy from a trusted local supplier.

Is 10 UK pounds plus VAT too much for a 65 watt per channel stereo power amp ??

.... Phil

I did buy this at Littlediode, (First time I've used them). I am now wondering if they are indeed a trusted supplier. It was shipped (according to them) from the far east, taking a week or so to arrive.

I woudln't normally do this, as if it is too good to be true then usually it is. Hence me buying another one from HHB who I trust implicitly and will have sourced the part from Genelec.

Unfortunately I paid more for postage from HHB than the entire Littlediode transaction cost!

Ho hum, and there's me trying to do the customer a favour.

Thanks for the info, when I get the other one back from the customer I shall break it open for comparison.

Gareth.

"Gareth the Menace "

** Are they " the new kids on the block " ??

Avoid them like the plague if they are.

** Verrrry suspicious.

Straight from eBay - to you.

** If it is an old example - it will look very different inside.

Probably be no SMD parts used at all.

... Phil

Funny how not even the OEM or replacement Genelec devices have any manufacturers ID. Doesn't fill me with great confidence, and the Genelecs are not cheap speakers.

Gareth.

The one WITHOUT the lot number on the back is the real Sanyo part.

Mark Z.

Thanks Mark, that's pretty much confirmed my suspicions then.

Gareth.

"Mark Zacharias"

** Prove it.

.... Phil

and

I would say the more precise script is on the genuine one. Rougher/less robust ink is probably on the copies/fakes. At least they did not make sham logos like the Philips , Fairchild, Linear Technology soics in an MBOX I was looking in recently

"Nutcase Kook "

** Therein lies the rub....

** ROTFL

Both are rough as guts.

** Not one scrap of proof exists to back that f****it assertion up.

... Phil

>

They are both genuine. They badge lesser spec'd devices to sell at a higher amount. I've seen this with projector TV convergence amplifiers. I try to buy from the manufacturer or a well trusted source.

--
Live Fast Die Young, Leave A Pretty Corpse

Interesting.

most of the failed power modules i have opened up show clear arcing on the power device slugs. They look relatively clear on yours.

It does look like a couple of the SMT transistors are damaged. Its kind of hard to tell from the picture if that's true or it was damage from prying the case off.

The epoxied power device slug leads do look a little close together on a couple of the output devices.

bob

Why would you mount them in a corner rather than the centre of the heatsink?

Gareth.

The back of the device is not the heat sink. Don't forget it is to be torqued down to a much larger heat sink where the location of the power devices within the package is insignificant.

--
Live Fast Die Young, Leave A Pretty Corpse

Oops, I did forget that.

Cheers,

Gareth.