The ClassicAPI JLS Inv-ACA PCB contains four active combining amplifiers (ACA) which are bussed into one output. You can use these ACAs to sum many channels into small groups before hitting ClassicAPI’s 2-mix amplifier.

Notable Features:

• Faithful replica of the ACA circuit from vintage API consoles
• Each PCB uses four 2520-style opamps
• Mounts easy on vintage API ACAs
• Can also be used at two 2-into-1 summing amplifiers

Price: $12 for PCB
More Info:

• ClassicAPI’s product page