Detail 01
25.78mm (1.015 inch) cup diameter
A step up from the 51. More lip in the cup broadens the sound but takes more air to fill and sustain.

Independent shopping perspective
Gold-plated large-shank trombone mouthpiece, 25.78mm cup. For tenor players on large-bore horns who want a broader sound than a 51 gives.

Strong match
Consider the trade-offs
What matters in use
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 01
A step up from the 51. More lip in the cup broadens the sound but takes more air to fill and sustain.
Detail 02
Wider than the 15/64 on the 46, 47 and 53. Less resistance, more volume available before the sound breaks up.
Detail 03
Fits large-bore tenor and bass trombone receivers only. It will not seat in a small or medium-bore horn.
Detail 04
Rounded rather than funnel. Gives a full, resonant core rather than a bright cutting edge.
Detail 05
Warmer, slicker feel on the lip than silver. The usual fix for players sensitive to silver plating.
Detail 06
Same rim diameter, shallower cup. Easier response and less air demand than the deep D and E cups.
Final check
Product questions
Straight answers to the questions shoppers most often ask about this product.
Same 25.78mm rim. The 52D has a much larger D cup and a 1/4 inch throat, aimed at symphonic playing and euphonium. The standard 52 is shallower and easier to control.
It will fit the receiver, but at 25.78mm it's small for bass. Schilke's bass models start around the 58 at 27.68mm and go up to the 60 at 29.03mm.
No — 0.15mm wider. The 52 gives a slightly broader sound. If you want a real size change, the 53 at 26.24mm or the 57 at 26.52mm is the next step.
The 52D is the model Schilke points euphonium players toward, since the deeper cup suits the instrument. The standard 52 is built around tenor trombone.
Reference
The complete catalog record, organized around the decisions musicians make when comparing gear.