hey,
i'm using a LM324 opamp configured as a diff amp. the inputs come from opamp followers, so there shouldn't be any loading issues.
when i vary the input connected to the inverting (-) terminal everything's fine - i see a clear change in the differential output. but when i vary the input connected to the non-inverting (+) terminal there's no change in the output. any ideas? (fyi, diff gain is currently 4.7 [470s over 100s])
thanks so much!, sam