The biggest changes to the ACP-8 were in the gate circuit. The ACP-8 had a FIXED ATTACK (Gate Opening) timing of 50 micro-seconds and a VARIABLE RANGE attenuation knob. On the ACP-88 we scrapped the VARIABLE RANGE in favor of VARIABLE ATTACK TIME (10 micro-seconds to 100ms) and put the RANGE ATTENUATION control on a two position switch ( -60dB or -20dB). The result is a gate that performs better on a variety of applications because of the ability to slow down the opening time. On the back we added a SIDE-CHAIN for the gate instead of just the gate KEY. This allows for Frequency Triggered Gating by inserting an equalizer.