This vintage King 3B Plus trombone, built in the early 1980’s, represents an interesting transitional period in King’s professional lineup.
It featured an 8" gold-brass bell, .525 bore lightweight nickel-silver handslide, and a standard-rotor F-attachment — a configuration that is no longer offered in King’s current catalog, where the 3B is available only as a straight-tenor.
During its production years, the 3B Plus occupied a valuable “middle ground” between the classic small-bore 3B jazz horn and the full-size .547 symphonic tenors.
Many advancing students and working players preferred it as their first F-attachment trombone because it retained much of the nimble, bright response of the 3B while adding the depth and low-range access provided by the valve section.
The instrument archived here was well-preserved — no significant flaws, no repairs, only minimal signs of use.
Its handslide was smooth and responsive, ready for immediate performance without further service.
For players in its era, it offered a professional-quality option at a price below the larger symphonic models.
Comparable current-production King 3BF or 4BF instruments today sell for over $2,900 new, but this discontinued 3B Plus often attracts interest from players who value its slightly lighter blow and balanced feel.
This listing now remains as part of our Archive of Sold Instruments, maintained for the benefit of musicians, collectors, and students researching historical King models and the evolution of mid-bore F-attachment trombones.
FAQ
What made the King 3B Plus different from the standard 3B?
It used a slightly larger .525 bore slide and included an F-attachment rotor, giving players more range and a fuller sound while keeping much of the 3B’s quick response.
Why was the 3B Plus discontinued?
As the market shifted, most players either stayed with the classic small-bore 3B for jazz or moved up to the .547-bore symphonic instruments.
King eventually streamlined the lineup to focus on the 3B straight-tenor and the larger 4B/5B series.
Is there still demand for the 3B Plus today?
Yes. Many players who encounter one in good condition appreciate its balance of nimble upper-register response and valve-section versatility, making it a sought-after choice on the used and vintage market.
Will a standard small-shank mouthpiece fit the 3B Plus?
Yes. Like the classic 3B, it accepts a standard small-shank tenor trombone mouthpiece.
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