Hirsbrunner Rotary BBb question

[Davidrn1]

Hi, I have a friend that owns a Hirsbrunner BBb Rotary horn. He said the horn is from the 50's and the rotors, he thinks, are from the 80's. He has been having a ton of problems with sticking rotors. He says that a few minutes into a gig the 3rd and 4th rotor get stuck. He has taken the horn to Best in Oakland twice. Same issue. Any ideas? This is all I know so far about the problem. Me thinks that the rotors need to be knocked out and cleaned. I doubt Best did not do this however. He said all problems started after he had it chem cleaned. I may be getting my hands on this horn on Wedneday to see if I can figure it out.

[Davidrn1]

Got it. Thanks Bloke! Glad it aint my horn.

[scottw]

What exactly is the "triplene core"?

[MackBrass]

There is basically a plastic core within the valve. The intention was to make the valve lightweight. Big problem with this design is that when the horn warms up, the valve expands rendering the horn useless. I owned on for a very short period back in the day and was doing an outdoor gig in Virginia Beach during the summer, outcome was not good. They can be changed out, but there will be a cost if you keep them HB.

[bort]

To me...

If it were a horn that was *perfect* for me apart from the valves, I'd consider getting them replaced. It wouldn't be cheap but it would be worth it to me if the tuba were otherwise great.

If the horn were imperfect in ways other than the valves, I'd sell it (preferably to someone in a cold place ).

[iiipopes]

Depending on the temperature range the horn will be put through, sometimes a lapping to another thou of tolerance will do.