MC1458, MC1558, LM5532 (?), NE/SE5532 Dual 741-type operational amplifiers. +----------+ 1.out |1 +--+ 8| Vcc 1.-in |2 1458 7| 2.out 1.+in |3 1558 6| 2.-in Vee |4 5532 5| 2.+in +----------+ [This information is part of the GIICM] You have a LM5532 listed at the bottom. Unless another manufacturer is making them, we never made a LM5532. The correct part number should probably be the SE/NE5532, a Dual Low Noise Audio Amplifier. Our exact equivalent is the LM833. Paul Grohe