There are 2 acts with this name:
1. Thrash Metal band from Ankara / Turkey
Rectifier was founded in 2004.Tangun Dinc(Bass/vocals),Taylan Paksoy(Drums) and Deniz Salgam (guitars)are the current line up.Rectifier was supporter band of EXODUS in 2006 (ankara concert). debut album will be out on the 18th of march 2008.
you can listen to their songs at www.myspace.com\rectifierthrash
2. http://www.discogs.com/artist/Rectifier - mysterious industrial-ish project from the United States.