Flexibility for Any Ensemble
Built for the professional player, the XO 1240L-T bass trombone offers the perfect amalgamation of traditional tone and contemporary playability. The 1240L-T is equipped with both F and Gb attachments and dual independent rotors, which give you a fully chromatic range of low tones. On top of that, the 1240L-T comes equipped with XO’s Thru-Flo valve, which effectively eliminates resistance as you blow. Each rotor has gold-plated channels for easy maintenance, and you’ll love the rich, colorful sound of the 9.5-inch yellow brass bell. Plus, the 0.571-inch bore lets you push plenty of air for powerful projection. What’s more, this trombone includes three interchangeable leadpipes that allow the player to customize the feel and response of the horn. Sweetwater Sales Engineers highly recommend the XO 1240L-T bass trombone if you’re looking for a horn that can hold its own in any ensemble.
Thru-Flo axial flow valve for a truly “open” sound
The trombone’s unmistakable sound is a direct result of arrow-straight airflow and cylindrical tubing. And as much as a trombone’s valve opens the door for extra-low playing, it can also color your tone in undesirable ways. That’s where the Thru-Flo valve design comes in. XO’s take on the well-loved axial flow valve, the Thru-Flo valve, eliminates the sharp bends found in traditional rotor valves for straighter airflow and less resistance than ever before. Trombone players at Sweetwater report that Thru-Flo valves provide a free-blowing feel that you have to experience to believe.

Powerful yellow brass bell
The XO 1240L-T ships with a highly responsive yellow brass bell. Measuring an expansive 9.5 inches, this bell delivers a rich, vibrant sound that rings clearly across all registers. The yellow brass gives this bass trombone a punchy, direct sound, making it ideal for bombastic playing in large symphonies, wind ensembles, and jazz big bands. You’ll appreciate the 1240L-T’s authoritative projection at loud dynamics and its nuanced response for quieter articulations.

Dual independent rotor valves
A bass trombone’s attachments are integral to the horn’s sound. XO knows this, which is why the company pulled out all the stops to produce responsive attachments to enhance your low end. This professional bass trombone comes equipped with dual independent F and Gb attachments, giving you a chromatic range of low tones that standard dependent systems cannot match. And since each rotor is independent, you get greater playing flexibility for technical passages. What’s more, XO includes gold-plated rotary channels to ensure upkeep is a breeze.
Customize your playing experience with interchangeable leadpipes
XO is committed to delivering the best possible playing experience with each of its instruments. A trombone should feel like a perfectly natural extension of yourself, and breath resistance plays a major role in achieving that “perfect” feeling. The 1240L-T comes with three interchangeable leadpipes, so you can customize the horn to fit your unique tonal needs. In addition, XO included a removable gold-plated counterweight to further customize the feel of your 1240L-T trombone.
XO brass meets the mark for today’s top players
The XO brand was born out of the vision of Koichi Haido, Chief Instrument Technician at the Global Corporation in Japan. Designed for today’s top players, XO brass instruments leverage the industry’s leading performance options. The company’s specially tailored features enhance the performer’s experience with incredible sound, clarity, and resonance, at all volumes, in all venues, and under any performance demand you may encounter. Each XO instrument is inspected for quality throughout the manufacturing process, ensuring it can endure bumps and bruises as easily as navigating challenging technical passages. Sweetwater strives to meet the demands of our professional-level customers, and XO instruments meet the mark.
XO 1240L-T Features:
- Top-notch professional bass trombone
- Dual independent rotor valves allow for a greater range of low tones
- Open-wrap configuration lessens resistance
- Thru-Flo axial flow valves effectively eliminate wind resistance
- 0.571-in. bore delivers a free-blowing feel and centered timbre
- 9.5-in., 2-piece yellow brass bell offers up a warm, rich tone
- Expertly fit yellow brass outer slide responds to your slightest touch
- Interchangeable leadpipes allow you to customize the horn’s response
- Gold-plated rotary channel makes upkeep a breeze
- Lacquer finish adds a warm quality to the tone
- Includes Session-style case and mouthpiece