> According to the Musical Engineer's Handbook (Bernie Hutchins, 1975), 3a
> (10), "The purpose of the resistor is to compensate for the offset due to
> the current that actually flows into the other input." It is important to
> use in precision DC summing circuits.
This is sort of a "hand waving" answer you write on a test when you forgot
the real answer :)
> The MEH also tells how to calculate the value.
Well that part is correct.
> I've wondered how important this resistor is in an inverting summer.
Application dependent.
I don't know the answers to question #2.
>
It's a toughie :)
Paul S.