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. Almost all of the 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. Total weight of the instrument is 4lbs.
  • Double independent rotary valves with bearings for very smooth operation.  From Instrument Innovations
  • .562 bore or .562/.578 dual bore
  • 9.5 inch bell
  • Curved Williams style hand brace for more comfort
  • Multiple leadpipe options.  Our multi threaded design takes both coarse and fine threads. (Shires or Edwards)
  • Ultra lightweight hand slide.  The outer CF slide weighs only 80 grams.
  • Butler Speedyflo © water key has a very large opening to allow for quick release of moisture. It does not change the flow of air through the tube as there is no “dimple” on the inside of the tube. It uses an O ring to seal the opening and has a curved shaped plunger that matches the inside wall of the tube. In addition it uses a compression spring for much longer spring life.

Instrument Innovations Bass Rotary Valves play more open than traditional rotary valves without the extra wind required by an axial flow. Ball bearing technology allows lightning fast, smooth, and quiet operation. The pressure releases at half stroke with the venting system, which is only possible because of their precision machining. No lapping required. The rotor rides between bearings which eliminates the abrasion that causes the valve to lose seal.




  • Threaded aluminum bell rings creating a two piece modular CF bell for ease of travel. ($350 option)
  • High luster finish ($250 option)






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