Kelly SKY-SS vs Yamaha SL-48S-GP
The Yamaha SL-48S-GP has a wider cup diameter, the Yamaha SL-48S-GP features a deeper cup.
Cup Diameter
The Yamaha SL-48S-GP has a cup diameter of 25.25 mm compared to 24.64 mm on the Kelly SKY-SS — a difference of +0.61 mm. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Yamaha SL-48S-GP has a medium cup while the Kelly SKY-SS has a shallow cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Material
The Kelly SKY-SS is described as 316 Surgical Stainless Steel, and the Yamaha SL-48S-GP as unspecified. Material affects mass, warmth, and how quickly the piece responds.
Which is better?
Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.
Compare Kelly SKY-SS with others
Compare Yamaha SL-48S-GP with others
Popular Trombone comparisons
- Yamaha SL-YEO-S vs Marcinkiewicz ET3C. Loper
- Giardinelli Sym. T vs Bach 12E
- Bach 12E vs Bob Reeves 5G Gladstone
- Schilke 45B vs Marcinkiewicz ET3C. Loper
- Denis Wick 6BL vs Conn Connstellation 7CW
- Bach 12E vs Bach Mega Tone Trombone 6½A
- Yamaha SL-48DL vs Yamaha SL-YEO-S
- Conn Connstellation 7CW vs Bach 6½A (small shank)