I have a Cerveny 641 E-flat 4-valve tuba, and I'm using a standard shank mouthpiece with an adaptor. Without the adaptor, the mouthpiece shank slides almost completely into the receiver. When I measure the small end of the adaptor, my calipers measure very close to 0.550", which according to some sources, a large shank mouthpiece would be more appropriate for the tuba. Any comments on this from any of you?
Does anyone know what would have been the original mouthpiece that came with these tubas?