TL072CP Op Amp Differences

I’m not sure what you mean. Where are you seeing a modern production silicon 1N34A? That JEDEC designation should only be for the germanium device.
This is mainly what I was referring to, customers are not getting a comparable germanium diode when they order the killer deal on 10 1N34A's from Shenzhen. They're getting intentionally mislabeled BAT4x, sticking them in their horse pedals, and lo and behold: they make the mythical sound.
 
This is mainly what I was referring to, customers are not getting a comparable germanium diode when they order the killer deal on 10 1N34A's from Shenzhen. They're getting intentionally mislabeled BAT4x, sticking them in their horse pedals, and lo and behold: they make the mythical sound.
I was confused because @jwin615 mentioned 'modern' datasheets.
 
I ordered some op amps from Mouser and they showed up labeled 29A8HSM. Hopefully these are good. (They seem good compared to the cheap Amazon ones I ordered last time.)
 

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A while back I (foolishly) considered some ebay "1N34A" and found a YT video where an old radio guy kinda went over it. They aren't made with germanium, but simply workalikes/workalites that have deceptive listing titles.

IIRC someone else here (or mbp forum?) basically said regarding any nondescript orange glass diode: they're schottkys. In the case of some of the workalikes, they have similar specs, I'm guess. Heck, that's what we do with some builds, right? Use a 1N60P or BAT41 for hard clippers. IDK, maybe I'm off. I'm ill and very sleep deprived.

An actually foolish eScam purchase a few years ago was for some "1N270" diodes, from a domestic seller, didn't seem like a MiC smurf account, although they're no longer active, percent due to things like this. Schottkys. Learned/relearned a lot in the last three years…

Edit:
This actually had a rather net positive effect, in that I essentially did a blind test on myself: I compared and extensively tested different specimens (and multiple sets ) of diode for a build and consistently picked those "1N270" schottkys as my favorite one in that circuit, thinking they were germanium ¯\_(ツ)_/¯
Sometimes the Schottkeys sound better than the germaniums, and sometimes they don't. I think the lesson learned is that when the internet gives you shottkeys when you thought you were buying germanium -- make lemonade.
 
Each time I get op amps, they have a different number ID on the top row. (Makes it difficult to know if you are getting the right ones.)
That's the manufacturing run number, and I've rarely if ever gotten chips all from the same run. Looks some members are keeping track of what are fakes though. I wouldn't be too concerned since you bought those from a large scale supplier.

Buying from digikey, farnell, mouser, etc. is the safest. If they sold bum components, they'd have a class-action on their hands, since they sell to all kinds of businesses, large and small.
 
That's the manufacturing run number, and I've rarely if ever gotten chips all from the same run. Looks some members are keeping track of what are fakes though. I wouldn't be too concerned since you bought those from a large scale supplier.

Buying from digikey, farnell, mouser, etc. is the safest. If they sold bum components, they'd have a class-action on their hands, since they sell to all kinds of businesses, large and small.
They showed up fast. I’ll likely be buying from Mouser when possible.
 
I ordered some op amps from Mouser and they showed up labeled 29A8HSM.
From https://e2e.ti.com/support/isolatio...-date-code-marking?keyMatch=DATE CODE MARKING and
  • The general format of TI's lot code is YMLLLLS, where Y refers to the year, M is the month, LLLL is the assembly number, and S is the assembly site.
  • Hence your chips were made in Sept 2022. (In principle, based only on the '29' alone it could also have been Sept 2012 or 2002, however Mouser/DigiKey/Newark/Farnell almost never hold onto parts that long.) I don't know how to decode the LLLLS info - I would tentatively guess that these are kept quasi-proprietary.
Mouser always delivers genuine parts, the only catch is that they only stock parts that are in production or have recently been EOL'd (in latter instance, they sell until their remaining inventory is gone). If you set up an account with them (usual email + password), they will notify you when any part you have previously purchased is about to go out of production - that way you can make a planned decision whether to order more before they go out of stock.
 
They showed up fast. I’ll likely be buying from Mouser when possible.
Mouser is good, and their parts are reliable, but they aren't always the cheapest option, and sometimes it's hard to find through hole parts once they have been discontinued from the manufacture. There are a few reliable suppliers like Stomp Box Parts, Small bear, Love My Switches, etc that often have better prices than Mouser. For something like a switch, you're pretty safe going to Tayda or LMS etc. For the more commonly counterfeited parts like TL072s and other ICs and transistors, it makes sense to go through an authorized dealer like Mouser
 
Mouser is good, and their parts are reliable, but they aren't always the cheapest option, and sometimes it's hard to find through hole parts once they have been discontinued from the manufacture. There are a few reliable suppliers like Stomp Box Parts, Small bear, Love My Switches, etc that often have better prices than Mouser. For something like a switch, you're pretty safe going to Tayda or LMS etc. For the more commonly counterfeited parts like TL072s and other ICs and transistors, it makes sense to go through an authorized dealer like Mouser
I get everything I can from Tayda and haven't had problems with counterfeit or faulty parts, but I've only been building pedals for a little over a year.

I have had problems with stuff from ebay and amazon. For me, those are always a roll of the dice.

Not only have I not had bad experiences at Tayda, but their pricing, shipping, packaging, and website are all remarkably good.

I'm always interested to hear examples of bad experiences, and if a specific part from Tayda is likely to be bad, I'd happily order it elsewhere, but I don't know of any.
 
For something like a switch, you're pretty safe going to Tayda or LMS etc.
Agreed, definitely - I rarely buy switches or hardware through Mouser for stompboxes.
But for transistors, ICs, diodes, and even capacitors that are in production - I lean heavily to Mouser.
Having quality parts is both time- and cost-effective for me, debugging questionable parts is a pain in the ass.
 
Not only have I not had bad experiences at Tayda, but their pricing, shipping, packaging, and website are all remarkably good.
Yep, I agree that Tayda is a great source. I think it's worth it especially since you can get pretty much everything in one order (except for those rare parts and the inevitable part that you forget to order the first time).
 
I've bought TL072 from Mouser, Tayda and one or two other sources. The ones I got from Mouser and Tayda have a circle near pin one, not the semi-circle notch at the end. Mouser is an authorized distributor and gets their parts direct from the factory. The printing and logo on the one on the right looks hokey.

Tayda probably buys most of their parts from distributors, some more reliable than others. I've never received a bad part from Tayda, but with the lower cost comes higher risk. You can be sure that to support the lower cost, Tayda does not test their parts and I doubt that their distributors do either.

Germanium diodes is a whole 'nother discussion. They can be legit and still unusable. Measure the leakage and its sensitivity to temperature. That will tell you everything you need to know about a particular Ge diode. Measuring Vf at an arbitrary current tells us nothing about how that diode will perform in a given circuit. It makes about as sense as comparing pickups based on their DC resistance.
 
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