How do I select operating voltage on my pre-v7 ParaEq?

The operating voltage of the Empress ParaEq is adjustable via an
internal DIP switch. You can access this switch by removing the back
plate. The ParaEq is initially setup to run from a 9V negative tip
supply, such as the popular Boss PSA-120. However, the unit will
accept voltages between 9V and 24V DC, provided the power supply
is negative tip. For maximum headroom, use a supply that operates
in the 18V-24V range, and is rated for a current of at least 130mA.
Here are the DIP settings for the various voltages: