One that I never get tired of Bruch's Violin Concerto No. ! Just threw a new set of tubes in my amp, some EL34's. Wanted to compare them to a new set of tubes that I just put in a few weeks ago. These are the first EL34's that I have owned. A bit less power, noticeable right off the bat, don't have the bass punch, but for violins and small quartets I think these might sound good.