Agree 200%. Just buy at the authorized distributors. Or directly from the manufacturer. TI will happily sell their parts to you directly. Good luck finding an AD797 in the TI store, though.
I do admire OP's quest to figure out what he actually bought. That has some entertainment value. Next step would be to decapsulate the parts with hot nitric acid and inspect the dice under a microscope to see if he guessed correctly.
Tom
The resulting distortion can seem like more detail, or good old expectation bias happens and the "upgrade" has to be better.
Not many chip rollers have an oscilloscope.
It's like the "LM2596" modules on aliexpress.
Yes, it's not a real LM2596, and it only delivers half the current it says it will, and the capacitors come from a dumpster in Shenzen so they will quickly die, and the output voltage will be way over spec when that happens, so whatever it powers will smoke...
BUT IT IS SO CHEAP!!!!!
Must be a good deal.
Yes, it's not a real LM2596, and it only delivers half the current it says it will, and the capacitors come from a dumpster in Shenzen so they will quickly die, and the output voltage will be way over spec when that happens, so whatever it powers will smoke...
BUT IT IS SO CHEAP!!!!!
Must be a good deal.
Indeed, and imho, most chip rollers are pretty clueless about electronics in general.
I mean, if they understood the circuits and the operating principles, they probably wouldn't bother with most of the 'rolling' of chips because the circuit is likely designed/optimised for the chip that came installed in it and therefore, changing the chip is going to have all kinds of unintended consequences.
After a couple of days my negative feedback for the fake AD797 has mysteriously disappeared from Ebay. (Seller Adeleparts2010.)
Now we know why there are no negative feedback ratings for these fake AD797. Apparently someone deleted the negative feedback. As far as I know Ebay is the only one who can do that.
I wonder what other online sites delete the negative feedback for fake products?
Now we know why there are no negative feedback ratings for these fake AD797. Apparently someone deleted the negative feedback. As far as I know Ebay is the only one who can do that.
I wonder what other online sites delete the negative feedback for fake products?
I reported this obvious fake to EBAY over a week ago.
Matched Quad 405 Replacement 2n3773 Transistors,best quality ever | eBay
It is still being listed.
Andy
Matched Quad 405 Replacement 2n3773 Transistors,best quality ever | eBay
It is still being listed.
Andy
Are you sure your feedback has disappeared?
That would be an extremely worrying thing if it is true.
Very sure. See the attached image. All the feedback is now positive again.
So much for trust/review based online marketplaces.
You can also see at this link: 10pcs AD797AN AD797ANZ Audio OP AMP IC ANALOG DEVICES DIP-8 | eBay
Attachments
Last edited:
Indeed. Even on China's Tmall they do publicly announce that negative reviews won't be allowed - eBay has sunk lower than Tmall as its passing off the reviews as genuine.
"Trustpilot " -UK have a policy that if a business complains the post can be taken down ---one of mine was in the past .
Whats surprising me is the naivety of people just because its a "Big Name " doesn't make it trustworthy.
An even bigger name is Which -UK -taken over by business/advertising types and some of the products they "sponsor " with "eco clean " etc fall apart after a year or two and don't even ask them to fight for reliability or the spares situation ---I could go on as I was associated with them but even the regular posters are upset with them but have to watch their words .
Whats surprising me is the naivety of people just because its a "Big Name " doesn't make it trustworthy.
An even bigger name is Which -UK -taken over by business/advertising types and some of the products they "sponsor " with "eco clean " etc fall apart after a year or two and don't even ask them to fight for reliability or the spares situation ---I could go on as I was associated with them but even the regular posters are upset with them but have to watch their words .
Did you get a refund? Does eBay delete negative after refunds?
Please can you try reposting the negative feedback and see what happens?
Yes, but my point is that Adeleparts2010 has sold thousands of these AD797 without a single negative feedback showing for that product. I don't know how many negatives were left and deleted in the past but I do know that the negative I left was deleted.
I would not have gone again my rule (of not buying op-amps on eBay or AliExpress) if I had not seen thousands of AD797 sold by that seller without a single negative review on that product.
So they have sold thousands of "AD797" marked chips (and also thousands of "OPA1612" marked chips) and not a single negative remains for those chips. So sadly it would seem that thousands of DIY audio types have fakes in their DAC and pre-amp projects.
Well someone said this on the eBay community help pages:
ebay removed my feedback without my consent - The eBay Community
I have not heard of fake PCM1794 before. Did you buy them or hear of them from someone else? Are they relabeled PCM1798 or something else? I have not heard of fake DACs. Mainly only electrolytic caps (like Nichicon and Elna), transistors (mainly power, driver, MOSFET, JFET and special small signal), WIMA caps and similar, op-amps and some Atmel Atmega chips.
I wonder if there are fake CS4398. My LJM CS4398 measures 20 dB better than my CERMECH CS4398 and my attempts to improve the power supplies, ground plane and op-amp never got it close to the LJM. It came with a fake op amp so perhaps the CS4398 is fake too???
I went back and measured the input offset voltage using both 2k and 10M as the resistor for the non-inverting input. The fake AD797 from Adeleparts2010 do appear to be bipolar input as they have volts of offset with the large resistor.
So the bipolar input type, low quiescent current, high input offset voltages, pin-out (pin 8 no connect) and the balance trim resistor values and configuration match LM741 or similar type.
They are not FET input.