C12 Bass trombone

“Carbon-12 (12C) is the more abundant of the two stable isotopes of carbon (Carbon-13 being the other), amounting to 98.93% of the element carbon;[1] its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 is of particular importance in its use as the standard from which atomic masses of all nuclides are measured, thus, its atomic mass is exactly 12 daltons by definition. Carbon-12; one of 5 elements in the human DNA is composed of 6 protons 6 neutrons and 6 electrons.” (Wikipedia)

C12 Bass trombone

This amazing instrument has all the sound qualities you would expect from a high end bass trombone but only weighs 4 lbs. Most of the total weight is centered over the shoulder to allow for stress free playing.

Price: $6950


  • Carbon fiber bell, tuning slide, outer hand slide, F slide and Gb slide.
  • Double independent rotary valves from Instrument Innovations
  • Curved hand brace for more comfort
  • Threaded interchangeable leadpipe
  • New Butler waterkey


  • Aluminum threaded bell rings with two piece CF bell
  • Multiple leadpipe options
  • Possibility of optional valve types with modular design


Douglas Yeo, bass trombone YAMAHA YBL-822 with carbon fiber bell, main tuning slide, hand slide by Butler Trombones

This is not the C12 but the sound is very much the same, (If you play like Doug…)

To read Doug’s blog post about the modifications to his horn go here: The Last Trombone