3 ms·

Reminds me a little of the two labs I've worked in in the course of my gravitational wave interferometry research in the LIGO collaboration. Analog electronics

Reminds me a little of the two labs I've worked in in the course of my gravitational wave interferometry research in the LIGO collaboration. Analog electronics are still (usually) far faster and far less noisy than digital as a way to implement feedback loops and frequency modulation/demodulation, and most of the best op-amps are 70s or 80s designs (e.g. TL074, OP27, LT1028, etc.). Our labs are full of them, and, they work at least as well as modern equivalents, so why not keep using them?

Yajirobe 6y ago
Because of planned obsolescence.
- johnr2 6y ago
  > Because of planned obsolescence. The TL07x series op-amps along with quite a few others have been in continuous production for over 40 years. They are still manufactured by the million. When is the obsolescence you refer to planned for?
jleahy 6y ago
The LF411 is nice and a modern design, so there have been incremental improvements.
- guenthert 6y ago
  The LF411 is more than 30years old and can be understood as an upgrade to the jellybean 741, but that one is quite shoddy by today's standards. With the JFET inputs and corresponding low bias current, it comes much closer to the ideal OpAmp than a 741, but there's little else speaking for it (well, it's cheap too). LT1028 OTOH is still the OpAmp with the lowest voltage noise afaik (which it buys with fairly high input currents and input current noise), it's still available, but it ain't cheap. There has been progress in other regards (lower supply voltages, lower power consumption, rail-to-rail operation, smaller packages), but clearly progress in the analog realm over the last forty years has been much more modest than in the digital.
aswanson 6y ago
Have class-D amplifiers changed much since that time period?
- amelius 6y ago
  Class D amplifiers have benefited a lot from better FETs [1]. But note that class D amplifiers are mainly applicable to relatively low frequencies. Perfect for audio, but not adequate above this range, see e.g. [2]. [1] https://epc-co.com/epc/cn/GaN%E6%8A%80%E6%9C%AF%E6%9D%82%E8%B0%88/Post/13752/Gallium-Nitride-Brings-Sound-Quality-and-Efficiency-to-Class-D-Audio https://epc-co.com/epc/cn/GaN%E6%8A%80%E6%9C%AF%E6%9D%82%E8%... [2] https://electronics.stackexchange.com/questions/223803/class-d-amplifier-working-outside-audio-range-frequencies https://electronics.stackexchange.com/questions/223803/class...

Yajirobe 6y ago

Because of planned obsolescence.

johnr2 6y ago
> Because of planned obsolescence. The TL07x series op-amps along with quite a few others have been in continuous production for over 40 years. They are still manufactured by the million. When is the obsolescence you refer to planned for?

jleahy 6y ago

The LF411 is nice and a modern design, so there have been incremental improvements.

guenthert 6y ago
The LF411 is more than 30years old and can be understood as an upgrade to the jellybean 741, but that one is quite shoddy by today's standards. With the JFET inputs and corresponding low bias current, it comes much closer to the ideal OpAmp than a 741, but there's little else speaking for it (well, it's cheap too). LT1028 OTOH is still the OpAmp with the lowest voltage noise afaik (which it buys with fairly high input currents and input current noise), it's still available, but it ain't cheap. There has been progress in other regards (lower supply voltages, lower power consumption, rail-to-rail operation, smaller packages), but clearly progress in the analog realm over the last forty years has been much more modest than in the digital.

aswanson 6y ago

Have class-D amplifiers changed much since that time period?

amelius 6y ago
Class D amplifiers have benefited a lot from better FETs [1]. But note that class D amplifiers are mainly applicable to relatively low frequencies. Perfect for audio, but not adequate above this range, see e.g. [2]. [1] https://epc-co.com/epc/cn/GaN%E6%8A%80%E6%9C%AF%E6%9D%82%E8%B0%88/Post/13752/Gallium-Nitride-Brings-Sound-Quality-and-Efficiency-to-Class-D-Audio https://epc-co.com/epc/cn/GaN%E6%8A%80%E6%9C%AF%E6%9D%82%E8%... [2] https://electronics.stackexchange.com/questions/223803/class-d-amplifier-working-outside-audio-range-frequencies https://electronics.stackexchange.com/questions/223803/class...