XO 1240R-T Jupiter XO professional bass trombone, SN ER01539. Single-owner instrument, purchased brand new just a few years ago and played very sparingly. It is in super mint condition, without any flaws or defects. Plays perfectly and looks stunning.
This model features a 9.5" rose-gold brass bell, providing a gorgeous dark, rich, and deep sound — the hallmark of this style. It has independent Thayer (axial flow) valves in Gb/D tuning, allowing for excellent airflow, smooth transitions, and an open valve register response.
The handslide is a standard weight .562" straight bore, offering great stability and a powerful low register while maintaining excellent clarity and articulation. It comes with three removable leadpipes, giving players flexibility to adjust resistance and feel to personal preference.
Mouthpiece and original factory case are included; the case is in perfect condition and has never left the house. Valve and slide action are both flawless — truly pro-level setup.
This model sells new today for over $7,000 (2025 pricing), with some "open box" listings seen as low as the $4,100 range. However, it is important for buyers to understand exactly what "open box" or "B-stock" truly means. While these options can appear attractive on paper, they often involve returned, demo, or partially serviced items — and unfortunately, some sellers violate manufacturer MAP pricing guidelines and do not disclose full instrument histories.
We know exactly the history of this 1240RT — it was purchased new by a long-time customer and friend of The Brass Exchange a few years ago. He has recently slowed down in his playing and decided he wanted to make it available to someone else who will really appreciate it.
If you'd like to learn more about what "open box" and "B-stock" actually entail, and why it matters when purchasing a pro-level instrument, please read our Open Box & B-Stock blog here.
For anyone looking for this model or a professional bass trombone in this configuration, this horn will not disappoint.
What makes Thayer (axial flow) valves so popular among bass trombone players?
Thayer, or axial flow, valves have become a top choice among modern bass trombonists due to their open, free-blowing feel and smoother transitions between open and valve notes. Unlike traditional rotor valves, Thayer valves reduce resistance and turbulence in the airflow, allowing for a more natural, even sound across all registers. This design helps produce a broad, powerful tone — particularly valued in orchestral and symphonic settings where projection and depth are essential.
This instrument has been sold and now remains in our archive for reference. Looking for something similar? Browse our current trombone listings.This instrument has been sold and now remains in our archive for reference. Looking for something similar? Browse our current trombone listings. 🔎
