5 valve 967 5050 acb adams advice antique audition auditionadvice auditions bach 6 1/2al backpack baritone baritone horn bass besson buescher buying buzzing career case cases compensating conn denis wick duplex eastman embouchure eminence euphonium euphonium mouthpiece euphonium quartet euphonium serial number for sale geneva gold grease guide hirsbrunner john packer miraphone mouthpiece mouthpieces prestige question range repair repairs sale schiller serial number silver slides solo sovereign sterling swelling tone trigger trombone tuba tuning valve vintage wessex wick willson wtb yamaha york