Overview
This King 4BF tenor trombone from the 1970s (serial number 693976) is a classic .547 large bore instrument with F attachment, presented here in fully serviced, player-ready condition.
It features an 8.5" yellow brass bell, traditional wrap rotor valve, and nickel silver handslide with yellow brass end crook. All parts and lacquer are original, and the instrument has been carefully maintained without any history of major damage or repair.
We completed a full professional shop service including chemical clean, rotor service, and slide optimization. The result is a clean, responsive instrument that is ready for immediate use.
Player Perspective
This is an ideal choice for a commercial player who typically performs on a King 2B or 3B but needs a reliable large bore tenor for occasional symphonic, concert band, or doubling situations.
There is a shared design DNA across the King line, and that shows up immediately in how this horn feels. Players coming from smaller King models will find the transition natural—articulation, feedback, and overall response remain familiar.
It is also a strong option for a player advancing into their first professional-level large bore trombone. The instrument provides the necessary size and capability for band or orchestral settings without feeling foreign or difficult to manage.
This example also includes an ergonomic nickel silver index finger support ring integrated at the mouthpiece receiver. It’s a subtle but useful feature that improves comfort and control—especially for players with smaller hands or those who prefer a more secure, relaxed grip during extended playing sessions.
Condition Summary
- Full shop service completed (chem clean, rotor service, slide optimization)
- Slide is smooth, well aligned, and free of plating issues
- Inner tubes are clean and perform properly
- Dent-free
- Original lacquer and components throughout
- No history of major damage or repair
This is a clean, properly functioning instrument that plays as it should.
What’s Included
- Original King case (good condition)
- No mouthpiece included
Fulfillment
This instrument is in stock and ready to ship from our St. Louis shop.
Orders are packed carefully and shipped via insured FedEx with tracking. Most U.S. deliveries arrive quickly due to our central location.
International buyers are welcome—please contact us for a shipping quote prior to purchase.
Questions Players Often Ask
Who is this King 4BF best suited for?
A great fit for players who primarily use smaller bore King models and need a large tenor for expanded repertoire. It’s also a smart choice for advancing players stepping into their first professional-level symphonic trombone.
How does a King 4BF compare to a Conn 88H or a Bach 42B?
All three share similar core specifications, including a .547 bore and 8.5" bell diameter. The Conn 88H is commonly built with a rose brass bell, while the Bach 42B is offered in both yellow and gold brass variants—both widely recognized as standard professional instruments recommended by band directors for decades.
The King 4BF approaches the same category from a different design lineage. It retains more of the characteristic King feel, which many players—especially those coming from a 2B or 3B—find more familiar and easier to transition into. The decision ultimately comes down to which design feels most natural in the hands.
Why Players Trust The Brass Exchange
Every instrument is inspected, serviced, and play-tested before listing.
Photos represent the actual instrument.
Condition is described clearly and directly.
Condition & Service Note
This instrument has been fully inspected and play-tested to ensure it meets professional performance standards. The slide is smooth and aligned, the rotor is functioning properly, and all components are operating as intended. It is ready for immediate use.
📌 Next Steps & Collector Insight
If this King 4BF is the type of instrument you’re drawn to, it’s worth spending time exploring how these horns have evolved across different eras. The feel, build, and response can vary in subtle but meaningful ways from one example to the next.
Interested in exploring more historical King trombones? 🔎 Visit our archive of sold instruments to compare models, periods, and condition profiles across the King lineup.
Considering a trade-in as part of your upgrade? Complete our Trade-In Form ✍️—many players use this process to move into a more refined setup with clarity and confidence.