The nonlinear gamma-tone filter replicates well the nonlinear properties of the cochlear amplifier. Discrete circuits show the circuit to be robust to design parameter variations and highly stable. By itself, this circuit has promise as a product, and as a front-end processor to speed simulation time it is also of value to our effort. We now see the need to have more filtering bands than can easily occupy board-level circuits. Therefore, we will build a 128 segment gamma-tone filter bank using on-chip operational amplifiers and off-chip passive elements. We have previously designed and fabricated these operational amplifiers, which are reasonable for a medium sized chip.