The Caroline Icarus 2.1 is in a league of its own. There’s up to +12db of clean boost with no additional gain just fromthe second (volume) stage, but once you add that gain and start to clipthe hybrid Russian germanium and silicon diode circuit, you won’t want to come back. Based onCaroline’sacclaimed preamp from the Parabola and Mtore, Icarus expands on it with the multiple gain stages, gently tapered highs control, and buffered/true bypass. All running elegantly at 9VDC with no noise-inducing charge pumps or other goofy frills.