Determine the value of a trombone by looking up its model number and serial number to find out the instrument's age, bell size, bore size, compatible playing level and age. Additionally, determining the type of brass the trombone is made of can help when estimating its value.
Most trombones feature a specific model number that allows professional trombone players to determine the bell size, bore size and compatible playing level of the instrument. Conn brand trombones feature this number stamped on the connection between the instrument's slide and the bell, while other companies stamp or engrave the number on the bell itself.
Typically student instruments cost less than intermediate and professional instruments due to the materials used and the level of care the manufacturer puts into the instrument's creation. Trombone manufacturers generally use yellow brass to produce student-level trombones, rose brass for intermediate-level trombones, and silver/nickel or sterling silver for professional-level instruments.
Another important feature that affects the value of a trombone is the condition of the slide. A trombone slide in good condition should move due to the force of gravity alone when the instrument is held at an angle. If the slide needs to pushed or pulled with force, it is a faulty slide that needs repair or replacement, as the instrument is not playable.