Are TL074s so expensive for people, or do yall need so many to justify this level of effort in not getting ripped off?
https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html
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You’re right there…
Getting ripped off on price alone is (kind of) ok, getting ripped off by getting fake chips adds insult to injury. They’re not really expensive, even good ones… However, even quality suppliers have been burned by fakes.
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Video on fake video:
tl;dw: In a sample of four, 100% correlation between real/fake and survived/didn’t survive an acetone wipe.
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Now we have to find a way to make an acetone wipe on the picture posted by the seller 
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Oh wait, got it wrong. #1 [(c) above] survived the acetone wipe but was fake. Detected via resistance measurements.
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As I just noted over here Matthew Skala (of NCS fame) got fake ones from Jameco that looked a lot like Christian’s samples, and he links to this thread in his article:
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thanks that was a good read , kinda scary though you never know what you are getting and if you don’t have the knowledge and gear to test you are kinda screwed . wonder if that could be the reason for some of the issues I am having with some of my modules . I did have some bad transistors once . luckily a friend of mine who has been a tech forever found the problem for me , to bad I can’t get his help more often.
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Well this definitely makes sense to me now why I’d been having so much trouble on another thread I’ve been troubleshooting a VCA I’d put together based on an old design. Even between the TL074s that came in the same batch there are quite big differences between physical packaging, labeling, and behaviour.
I’d swap out for another and everything in the circuit would be quite different again. Nothing would behave, and I was getting quite a lot of distortion.
I’ll have to have a go at acetone wiping, but being that at the moment there are huge stock shortages it seems here with aussie distributors (RS components has them listed as backorder only) I’m going to have to be patient before I can try a real one in the same circuit.
EDIT:
I’ve just dropped each of the TL074s I have here (8) into my VCA circuit I’ve been tinkering with. Some stay high, some sit at ground, others kind of work but distort. They’re all over the place. Also an acetone wipe didn’t seem to affect them - they definitely had laser etched tops, but they are definitely quite different to each other. I bought them from a place that’s normally quite reputable (WES electronics) who I do love, but perhaps they’ve been bitten by an upstream seller at some point.
I’ll wait until my next big Mouser order and get some that should be trustworthy to see if they act differently.
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Have you asked them for a replacement?
Would you be so kind to upload some pictures of the ICs so that we can have a look at the different packagings, brand symbols and (laser)prints?
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I haven’t - TBH I bought them about 4 months ago and hadn’t used them yet, would feel a bit cheeky to go “oh hey that stuff I bought ages ago from you now seems to have a problem”. I’ll suck it up for now, they’re my go-to supplier for weird long dead transistors etc when I repair arcade machines from the 70s - I managed to find NOS of a Japanese transistor that hasn’t been made since 1978 to repair the CRT drive circuit of my original black and white cocktail table space invaders. I was so stoked!
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Well this gets increasingly interesting. These TL074s that I assumed to be fakes as they all behaved differently from each other and also didn’t work in a VCA circuit designed for them, seem to work fine in a kickdrum module I just built and thought I’d try just in case.
It’s possible there’s something just super weird going on with my VCA, and after days of trials decided it must be the TL074s at fault. Also weird is that they behaved differently to each other so much, but in this kickdrum module they all perform the same…
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kind of expensive but it is as advertised 12 fake chips lol .
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hey so lets drill for oil and dig for coal …
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I actually got some of this “kind” on ebay (for tl074).
Edit : exactly like this : Two for the price of one? - #2 by analogoutput
They do look as they are not from texas instruments but they did the job nonetheless. But I do not have a proper oscilloscope so 
I’ve occasionally seen claims that Tayda sells fake chips. It wouldn’t surprise me if they have at one time or another. Apparently Jameco, a fairly reputable vendor, shipped some TL074s that turned out to be fake once; if they could get burned by a supplier, so could Tayda.
But I’ve bought most of my chips from Tayda since 2019, and not one has given me any problems.
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