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A Selmer trumpet with a serial number of 43417 was made in 1950, so as of 2013 it is 63 years old. All Selmer trumpets have a serial number and there is a chart that shows what year the trumpet was made.
It is a Getzen serial number.
Best estimates put this trumpet as being manufactured after 1984.
A serial number is needed to determine the age of a Bach Stradivarius trumpet.
There could be a number of things in the bell. Clean it with a trumpet cleaning snake and run water through it.
It depends on the serial number.
Serial number
Best estimates put this trumpet as being manufactured after 1980.
Best estimates put this trumpet as being manufactured after 1983.
I think the value of your trumpet depends more on the model of your trumpet, how old it is and of there's any dents or if any part of your trumpet docent work.
K 330 through K 333 are wonder sonatas, I would suggest all of them equally. Also, maybe the a minor (the number of which escapes me); though it might be overdone, it is likely the most virtuosic of his sonatas.
If it's a Conn trumpet, it's the model number. The Conn 20B is a student model horn.