Sinewave is a spinoff brand started by Chad Mangrum, previously of Two Rock. The Contiuum is the identical circuit to the TR John Mayer Signature, which were built in a very limited run in 2007. The end result is exactly what you'd expect from the original, at slightly reduced price, given the relative obscurity. This amp has been very well kept it's entire life, and has only minor signs of previous wear. For anyone in the market for a Two Rock head, this Sinewave is a no-brainer.