Ciao Renaud. In 1961, after switching to Bass Trombone, on the advice of my teacher at Berklee, Herb Pomeroy, I called Al Cass to buy a mouthpiece for Bass Trombone. Al said, "I've made every brass instrument mouthpiece except for Bass Trombone. Would you like to be my 'guinea pig'?" "I've just switched to Bass Trombone and am just learning to play it". "Perfect! You are exactly what I need", he said. The rest is history. He will have an entire chapter in my book, THE TROMBONE AND I. As soon as my book is finished you will receive a copy. There is a full chapter on Al Cass including our extended relationship as we worked to perfect the bass trombone piece.
Look at Al's promo sheet. There is a picture of me with Al along with my late friend, Jerry Puleo in uniform. Jerry was a trumpet player. I took him to Al. He switched to Al's piece and played on it the rest of his life.
There are four pieces. My trumpet piece was stolen with my trumpet. From left to right they are; Tuba Bass Trombone ( #5 ) Tenor Trombone ( T1 ) French Horn with trumpet rim.
standing lying down showing shank ends
lying down showing rims and cups.
Notice that tuba, bass tbn and tenor tbn all have the same outer rim, the tuba has a lightly larger inner rim. All Al's trumpet rims are the same size for trumpet, cornet, flugel horn and F horn. All my pieces are gold plated.
I'm very happy that you have paid tribute to Al Cass. I have never understood why music teachers never put his doubling rim invention to work.