570 Series 4-Valve Euphonium 570L Lacquer. The 570 Tribune Series Euphonium offers top design in a non-compensating instrument. The 570 Series features a traditional 3+1 valve design with 3 top action valves and an angled left hand 4th valve to eliminate the use of the right hand pinky finger. This design is very comfortable to hold and play. The .570 inch bore offers a warm, rich euphonium sound perfect for band and solo work.