Effects of Opamp Loading?

[Shredhead]

Hi guys,

Someone warned me recently about picking too small of resistor values to put into op amp buffer circuits.  He cautioned against "loading" the op amp. 

I don't know what that means.  What would the effects of that translate to in an audio circuit?  Increased THD, clipping or something like that?

[retrolefty]

Certainly could. All opamps have some finite output current limit value where exceeding it will cause problems and/or specification degradation.

[David Hess]

Excessive loading will degrade the precision of the operational amplifier via both heating of the IC and lower open loop gain.  If this is a problem, then adding a buffer stage to the output but inside the feedback loop can help.