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Hirsbrunner Rotary BBb question
Posted: Tue Dec 20, 2011 6:34 pm
by 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.
Re: Hirsbrunner Rotary BBb question
Posted: Tue Dec 20, 2011 6:44 pm
by Davidrn1
Got it. Thanks Bloke! Glad it aint my horn.
Re: Hirsbrunner Rotary BBb question
Posted: Tue Dec 20, 2011 10:23 pm
by scottw
What exactly is the "triplene core"?
Re: Hirsbrunner Rotary BBb question
Posted: Wed Dec 21, 2011 9:12 am
by 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.
Re: Hirsbrunner Rotary BBb question
Posted: Wed Dec 21, 2011 10:44 am
by 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

).
Re: Hirsbrunner Rotary BBb question
Posted: Wed Dec 21, 2011 11:36 am
by iiipopes
Depending on the temperature range the horn will be put through, sometimes a lapping to another thou of tolerance will do.