Electronics > Beginners
Jellybean hobbyist general purpose transistors..
floobydust:
I don't know the politics of jelly bean transistors. TIP31 is the cheapest TO-220 in town and not very sexy.
I believe all these old parts got moved over to modern lithography, standard semi fab processes.
Any improvements in the technology gave a "die shrink" to get costs down and fT up.
I learned from IC's such as Signetics/Phillips/Raytheon NE5534 which I think was 28 masks.
The TI NE5534 part behaves totally different, so I called them and asked WTF. They told me they purchased the rights and are using modern op-amp lithography/standard process that still "meets the specs" of the old part. So it's a different part with an old number and new fab process. Old parts don't have a lot of tests and datasheet specs so they are easy to rip off.
The TI NE5532 I found terrible, literally kicked out of a recording studio for using it in repairs. Noisy and crappy sounding, compared to the old Signetics version.
exe:
--- Quote from: floobydust on October 18, 2017, 02:19:53 am ---Old parts don't have a lot of tests and datasheet specs so they are easy to rip off.
--- End quote ---
Yeah, this what I don't understand at all. There are many parts with the same part number, but from different manufacturers. And they are different! Esp. opamps. How can I make purchase decisions? For example, I measured bandwidth of NE5532 from TI and from ONSemi and there is a noticeable difference. Same for MC33079. Or transistors, I found 2STA1942 from ST to be better in my use-case than corresponding part from Toshiba (although, I tested only one of each).
What's worse, nobody tests this. And even worse, manufacturers keep adjusting their processes... And on top of this a lot of rumors (esp. about audio stuff where audiophiles "reason" about sound quality with no understanding of how opamps work and no measurements).
Vtile:
Most of the shared parts what I see, are from the low end and/or old designs. OPAs in general aren't "amps" in sense of audio amp, but arithmetic calculators. If I set up the LM358 as a PID-controller I doubt (since I haven't tested) that I would see really any difference between the manufacturers. :)
bd139:
This is why people buy stuff from Linear.
Datasheets not datashits and proper specifications that are reliable.
T3sl4co1l:
--- Quote from: exe on October 18, 2017, 10:20:53 pm ---What's worse, nobody tests this. And even worse, manufacturers keep adjusting their processes... And on top of this a lot of rumors (esp. about audio stuff where audiophiles "reason" about sound quality with no understanding of how opamps work and no measurements).
--- End quote ---
If it meets the datasheet, and your application works based on datasheet information, then you're fine.
A perfect reason against designing something to be critical on the parts used. Like hFE ("suicide") versus emitter degeneration bias, to use a simple and popular case. ;D
Tim
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version