One of my trumpets is a YTR-2335 that was purchased used from a music store manager. The valves developed a very minor sticking problem where they would drag a bit as they recoiled. No amount of cleaning or oiling seemed to help. Took the horn into the U.N.T. School of Music Brass Shop and had the pistons custom hand lapped. Now all I can say is...WOW! They are insanely smooth, lightning fast, but still not quite as quiet as the valves on my 3001MV Getzen. For those of you that do not know, U.N.T. is the largest music school in the USA, and home to the world famous 1 O'Clock Lab Band. Big band jazz is alive and well here in North Texas!