[sdiy] Voltage Feedback Resistors and Circuit Stability

[tpuefke]

I was hoping someone more experienced could help shine some light on this issue. This is still quite puzzling to me as a non-engineer.

Looking through my collection of schematics from various places like MFOS (bless his soul), I see a lot of the standard 100k resistor in negative feedback op-amp configuration, for inverters, mixers, attenuators... For a long time i have been adapting these as my go-to values without giving it much thought and usually it works pretty well. The odd schematic here and there uses lower values.

Considering that high feedback resistance implies a higher gain potential, shouldn't lower values (e.g. 10k, 1k even) usually be a better choice in terms of circuit stability?
Or is this a non-issue for fractional gain setups?

I've been wondering about this for a while now and recently stumbled across this post discussing Rf values and op-amp input capacitance:

https://www.analog.com/en/analog-dialogue/raqs/raq-issue-122.html

What are the pros and cons in your experience for using high resistances like these, in attenuator / unity inverter setups especially?

Higher resistances simply to reduce current consumption in bigger circuits? What about resistor noise?

Just trying to wrap my head around this to be able to make more informed decisions.
Any feedback is HIGHly appreciated. :)

thanks,
Tom
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