API Audio 1608 Recording Console - Manual (Page 27)

26
4.0 168B Summing Bus Sub-master Module
The 168B Summing Bus Sub-master Module provides control and routing for
the eight Summing Buses, also known as Active Combining Amplifiers (ACA).
The following is provided for each Summing Bus (ACA):
 On/off switch
 Solo (PFL and AFL only)
 Trim control
 ACA calibration
 Individual Left and Right Program Bus assignments
 Balanced, line-level outputs