I've been playing a 19 inch bell B&S tuba for the last 10 or so years. It is visually quite similar to a PT-6, and when I bought it from Dillon Music, it was advertised as such, but I know B&S has made instruments that look very much like PT-6's but are not. Is this a PT-6? And what exactly is a PT-5?
(Full disclosure, I started down this journey of trying to figure out what my instrument exactly is because I'll be selling it soon, and I'd like to be certain of what I have).
This is what my tuba looks like (note: the leadpipe was moved a bit higher by a previous owner)


I can't tell any difference between this instrument and modern PT-6's with regards to the wrap of the tubing. Some older B&S tubas of this size have their main tuning slide exit routed through the third valve tuning slide, which is not the way a PT-6's main tuning slide is routed. A few examples of that from tubenet:
viewtopic.php?f=4&t=41289
viewtopic.php?t=55163&p=470278#p470289
I've seen these differently wrapped tubas with 19 inch bells called PT-5's, but I've also seen instruments wrapped like mine called PT5's as well. For example, this B&S advertisement Neptune posted here viewtopic.php?f=2&t=32059&p=281539&hilit=PT5#p281372 and this horn that was listed for sale as a PT-5 from a while back http://s149.photobucket.com/user/euphba ... t=3&page=1
So, are there 2 instruments that B&S called the PT-5? Is one of them identical or nearly identical to the PT-6? What on Earth have I been playing for the past 12 years?!? And can we get to the bottom of this by measuring our tubas?
On the collar that attaches my bottom bow attaches to the bell, my instrument measures about 16 in.
On the collar that attaches the bottom bow to the top bow, my instrument measures about 11 and 1/2 in.
If some other PT-6 and PT-5 / mystery B&S 5/4 owners chimed in with their measurements and tuning slide wraps, it would definitely be appreciated!