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0 pointsformerly_proven5y ago0 comments

Also especially for audio stuff it's not like all op amps have to be high spec. At the edge (input/output) components matter much more than inside the circuit, where levels and impedances can be designed in. A low-noise BiFET op amp makes a ton of sense for pre-amp, but as a generic buffer or whatever amplifier between stages, not so much. Even in 2020 a NE5532 is a fine choice in those places.

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dragontamer5y ago· 1 in thread

In general, you can always substitute a high-quality, expensive op-amp for a cheap op-amp.

From the perspective of a hobbyist with limited space: you want to minimize the SKUs that you stock in your personal shelves. Buying a higher-end op-amp and spamming it everywhere (even when its specs aren't needed) is far simpler than buying 10x different op-amps at the $0.50, $1, $1.50, $2, $3, $4, and $5 price points.

Just keep a supply of higher-quality $5 rail-to-rail low-bias op-amps at the voltage-level (3.3V for most Arduino projects).

Yeah, there's probably a $0.50 op-amp that does the job. But do you really want to keep another SKU on your shelf and keep track of it? There's simplicity in just buying over-specced parts for personal hobby projects.

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Well... maybe keep a stock of the $0.50 stuff too (EDIT: Ah right, LMV358. That's the cheap part I keep around). But I think you get my gist. Personal-supply closet management is certainly a problem for the personal hobbyist.

segfaultbuserr5y ago

> In general, you can always substitute a high-quality, expensive op-amp for a cheap op-amp.

Yes, it will work in general. Unless the expensive opamp has a significantly wider bandwidth, then one must use with caution. Switching from a low bandwidth opamp to a high bandwidth opamp is especially problematic, the loop characteristics are different and it may need additional frequency compensation or bandwidth limiting, the original layout may become inadequate, etc. More often than not, a blind replacement make it oscillate like crazy.

Sometimes having a bunch of cheap opamps makes life easier.

And financially - your heart and wallet won't start bleeding when your $0.5 opamp is unexpectedly zapped by ESD, cooked in soldering, or fried in an overload. Killing a $10 ASIC is a big deal (just did that last week while prototyping an ASIC controller, but there isn't anything cheaper on the market).

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