Posted by Rob P-M on October 07, 2002 at 10:34:26:
In Reply to: 20K Model Number posted by LZ on October 07, 2002 at 00:14:13:
Most 20K's are stamped on the bell collar and on the bell itself. Older ones (pre-WWII) may have additional numbers which would indicate the finish. As someone said, it is easy to indentify a 20K by the 'short action' offset valves and the oval valve ports. I have seen a 20K that was not stamped, and wondered if the bell collar had been replaced.
If the horn looks exactly like a 20K, but does not have short action valves or oval valve ports, it is probably a 38K Sousaphone Grand, the predecessor model with regular valves. With four valves it would be a 40K.
If the horn looks like a 20K, with short action valves and oval ports, but has four valves, it is a[n extremely rare] 24K.