I believe I remember reading in an older ITEA Journal that it's a B&S PT-3P with a detachable bell....although it could be a PT-4P. Either way, Jack Tilbury sounds phenomenal on whatever he plays!
It is a silver tuba with piston valves. That can only mean:
1. It isn't as good as a brass one with rotors.
2. It isn't as good as a silver one with rotors
3. It isn't as good as a brass one with pistons
4. It ain't a helicon
5. It ain't a 14K
6. An E-9 is worth more than 2 E-6's, so maybe it is a great horn
7. Tilbury is in the Army, Sheridan was in the Marines, so maybe it is an OK horn afterall, with the possible exceptions of 1-5 listed above.
Does that cover it Joe? Oh yeah, if that horn was within a 100 miles of a DCI event, are all bets off?