PT mouthpiece question

[joh_tuba]

The PT65 is 'undercut' meaning that the bowl is slightly larger than the rim. That's the only immediately obvious difference from a visual inspection. Sonically, the 64 is brighter and more 'direct' in terms of the sound produced. I think it more obviously favors the 'German' F tuba sound. The 65 in comparison has more meat on its bones.. More warmth/depth. Neither is better or worse, just different flavors. The differences are relatively subtle and clearly part of the same family. Both the 64 and 65 are default gold standard recommendations for any level F tuba player. I think they are an especially smart choice for a beginner since they aren't anything radical. I've since found myself seeking other alternatives but wouldn't feel held back in the least by either PT.