Brand
Vincent Schrottenbach was born near Vienna in 1890, landed in New York in 1914 and started calling himself Vincent Bach. A repairman ruined his mouthpiece, so in 1918 he started making his own, and in 1925 he sold his first Stradivarius trumpet. Trombones followed after the move to the Bronx in 1928. In 1961 Bach sold the company to Selmer, which moved production to Elkhart, Indiana, in 1964 and bought Conn's old Elkhart plant in 1970 for Bach. Stradivarius trumpets and trombones are still built there. Selmer also kept Bach on to design student brass, and the TR300, TR400 and TB300 you see on eBay belong to Bach's student line, which now uses BTR and BTB numbers. Prelude and Aristocrat are imported stencil brands. The serial is the quickest tell. A Stradivarius trumpet has a plain number of six digits or fewer stamped on the second valve casing, while a Bach serial that starts with a letter marks a student or intermediate horn.
5 models we cover.

Bach · Trumpet
StudentTR300
$310–$625 typical ask
71 on eBay

Bach · Trumpet
StudentTR400
$1,425–$2,175 typical ask
10 on eBay

Bach · Trumpet
Professional180S37 · Stradivarius
$1,725–$2,225 typical ask
118 on eBay
Bach · Trombone
StudentTB300
$230–$480 typical ask
7 on eBay
Bach · Trombone
Professional36B · Stradivarius
$1,750–$3,850 typical ask
18 on eBay