Something I would like to mention – before a processor – the CL-1 Cloudlifter from Cloud. +25dB of gain, with no resistors/capacitors – 4 JFETs. Clean, colorless gain for low output mics (SM7B, RE20). I have 4 VO studios at my station, and have loved them before and pres. They power from your pre-amp’s phantom power.
I cannot say enough great things about the Cloudlifters. Completely made my (and the student’s) voice tracks sing. Killed any preamp hash/noise.