I think the DEQ2496 mic preamp is for use with the device itself internally. I don't believe you can break out and send the preamp line output to another device.
The behringer phantom power supply you referenced is a power supply only and not a preamp (which is required). You would need a full microphone preamp with phantom power for the ECM8000, such as the one most people use from behringer =
XENYX 802.
brucek