But there are a number of recordings where Conrad is identified as playing with Arthur Pryor's Band during those years, and some of those can be listened to here at the National Jukebox, courtesy of the Library of Congress. The tuba part really shines in "The Girl I Left Behind Me," "Arkansas Traveler," and "Reinzi Overture."
Better still, I was able to get access to a very rare recording of Gilmore's Band from 1891 that almost certainly includes Conrad on his monster helicon. Conrad had emigrated from West Prussia to America just a few years earlier, and here he was, recording with what was hailed as "the greatest band in the world"! And he was only 24 years old!
Here's another number from that same recording session in 1891:
But I've saved the best for last: Conrad was featured in what was called a "tuba solo" in a special 1902 recording, while he was still with Sousa's Band. Is he playing his Sousaphone? We can't be sure. But this piece does bring Conrad to the front of the band for a change. Enjoy!