The voltage and current requirements for the ParaEq depend on the version you have. To determine the version, see this.
For a version 7 ParaEq, 85mA of current are required, with a DC voltage between 9V and 18V, negative tip. Different voltages don't change the amount of headroom. All input voltages are regulated down to 8V and then doubled, giving you a lot of headroom!
For a version earlier than 7, the current required depend on the voltage you're supplying. Before plugging a voltage greater than 11V into a pre-version-7 ParaEq, you must change the internal DIP switches (instructions on how to do that can be found here). The greater the voltage supplied, the greater the headroom. Here's the current required given the input voltage:
|Input Voltage (DC, negative tip)||Dip 1||Dip 2||Dip 3|
|9V - 11V (75mA required)
|12V - 17V (95mA required)
|18V - 24V (130mA required)