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I saw mentioned in another question that a 741 is one of the worst designs. An LM324 is also pretty low-end.

Is there a better low-end operational amplifier for the money? I would just appreciate knowing a hierarchy of people's favorites. Obviously, if I can get LM324 for 0.18, it's not comparable to a higher end opamp costing $4. I think the fact that the LM324 is a quad is very useful for class because we can use one chip to build a positive feedback amp, then a negative feedback with a source follower front end, and finally a differential amplifier, all with a single chip. So all things being equal I guess I would tend to prefer quad packages over others for that reason.

So I'm looking for the best opamp/$ in 3 categories:

classroom use
low noise/higher speed (say, in the 10Mhz range rather than 1Mhz)
Power (10W or thereabouts)

In addition, after reading a question here about differential amplifiers I looked on Avnet to see what I could get in a single package. I found some really nice ones, but only in surface mount packages. Is there anyone selling differential amplifiers in PDIP format so they can be used in class? They are pricier as well, of course.

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    \$\begingroup\$ You can get a lot of useful stuff done with the LM324. Get a handful of those, especially since it won't cost much. Just be mindful of the not super high imput impedance. Fot class purposes, just make sure your signals are a few 100 kOhms or lower and all will be fine. For dual supply, the TL074 is nice, just mind the several volts headroom it needs at each end. \$\endgroup\$ Oct 17, 2012 at 23:06
  • \$\begingroup\$ Why do you need/want "high speed" opamps in a classroom setting? The higher the bandwidth the more prone they are to oscillation so you need to be more careful with circuit designs and layout. Assuming your signals are all in the audible range old and slow can actually be an advantage. \$\endgroup\$
    – Frosty
    Nov 7, 2017 at 18:06
  • \$\begingroup\$ Also, 10W opamps are a pretty specialized (hence expensive) parts. Are you just looking for moderately powered Audio amplifier ICs? \$\endgroup\$
    – Frosty
    Nov 7, 2017 at 18:35

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Some of my favorites:

general purpose - TL084

higher speed - AD817 (GBW of 50MHz)

instrumentation - AD620 (not the best anymore, but a $4 part)

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    \$\begingroup\$ AD620 is nearly $8 in in single quantities (DIP package) at Digi-Key. I just used a AD623 in a project, and it really is $4 in single quantities (also DIP package). \$\endgroup\$
    – tcrosley
    Oct 17, 2012 at 22:27

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