Posted by Shon on May 19, 2002 at 20:50:09:
In Reply to: Getzen CB-50 5th valve posted by Doug on May 18, 2002 at 23:19:44:
Here's my understanding of what Getzen intends. My CB-50 came with two 5th valve extenders. The shorter one is the correct length to drop the pitch by a whole step and is used to put the entire tuba in BBb. To do this, you have to disconnect the linkage from the rotor, then rotate the rotor by 90 degrees and re-attach the linkage. This effectively makes the 5th valve slide part of the "open bugle" thus dropping the pitch by a whole step. Pressing the 5th trigger then raises the pitch by a whole step. Of course, once you've converted the 5th valve to put the horn in Bb you need to pull the other 4 valve slides to put them in tune. My CB-50 ends up being pretty stuffy when "converted" to Bb so I've asked Lee Stofer to investigate the practicality of making a complete set of slides (main tuning slide, plus 5 valve slides) to convert to a normal 5 valve BBb tuba (for playing brass band parts that clearly weren't meant to be played on a CC tuba). He's still checking on availability of parts.
The longer extender is the normal flat whole step extender used to play low F in tune (when playing as a CC tuba). According to Fedderly, many people that own CB-50's or G-50's find this extender to be a little too long so they use the shorter extender and just pull it to the desired length. The longer extender works fine for me so that's what I use.
Hope this helps. Enjoy your new horn!