The circuit for the Revision-A EAS active subwoofer equaliser is as shown in the project article. It is very simple to construct, and you may use an on-board single gang pot (9mm miniature pots fit on the board). All components including the phase reverse switch and gain control mount on the PCB.

Like most ESP projects, a power supply is required. This PCB can be powered from your preamp supply (typically the P05), or any source of ±12V to ±15V. Alternatively, any source of clean DC within the stated limits may be used. The original PCBs are no longer available.

Order Code	P48
Size (mm)	64 x 38