Universal Audio Solo/610 Tube Preamplifier and DIThe Universal Audio Solo 610 Tube Preamplifier and DI brings the classic 610 console sound to a single channel, portable format with mic, line, and instrument paths that range from clean to confidently saturated. The front end is simple by design. A stepped Gain control drives the tube input stage while a continuously variable Level sets output, so you can hit gentle harmonic lift for vocals or push the circuit for thicker bass and guitars without