I never bought into the fetish for the JRC4558 chip, nor the endless arcane Tube Screamer folklore. Having said that, this is a very good, relatively inexpensive drive. It gooses the 6SL7 based front end of my amp, adding a nice dose of grit, while not screwing with the lovely wide harmonic range of this big bottle, octal base honey. I would recommend it for anything without a master volume, especially any old Ampeg, Tweed or Blackface design. You get a lot for the price.
New York, NY