Sure, go to the hardware store and buy a 12 gauge extension cord of the required length. You can make yourself one if you wish. Buy a male and female end and some 12/3 cab tire (sjoow or soow) off the rack at the hardware store.
The voltage you measured is acceptable. The utility usually guarantees +/- 5% @ 120v.
Cheers, Brendan
Thanks Brendan!
I ended up ordering a Startech 10 Foot 14 AWG extension cord from Amazon which arrived yesterday.
The cord is an exact match in thickness and appearance to the OEM EP500, and I can now reach the Furman unit.
For anyone else needing a cord for subwoofer I would highly recommend this one:
Amazon.ca - Startech 10-Feet 14 AWG Extension Cord