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Have you ever converted a 20J into a 3+1?
Posted: Mon May 28, 2012 4:57 pm
by Mike-ICR
I've got a chance to pick up a great looking 20J for a great price and would like to add 4th valve. The trouble is I don't have the parts or patience to add an in-line 4th and don't want to convert it to a front action horn. Has anyone ever added a 4th (standard, not short action) to be used by the left hand, like the British basses? Pics or advice would help. Thanks in advance.
Re: Have you ever converted a 20J into a 3+1?
Posted: Mon May 28, 2012 5:31 pm
by Dan Schultz
The easiest way (I think) would be to put a rotor just before the main tuning slide. That way... you can put the operating mechanism about anywhere you like. A .750" rotor (or a dab larger) should be pretty easy to find.
Re: Have you ever converted a 20J into a 3+1?
Posted: Mon May 28, 2012 8:22 pm
by The Big Ben
I saw a horn at TubaChristmas which had a piston valve added. It stuck out of the side as on a euphonium. Didn't get a picture or a really good look. The 3v setup would not have to be disturbed and the 4th valve would be where you could operate it with your left had.
Re: Have you ever converted a 20J into a 3+1?
Posted: Mon May 28, 2012 8:28 pm
by Dan Schultz
KiltieTuba wrote:TubaTinker wrote:The easiest way (I think) would be to put a rotor in the main tuning slide. That way... you can put the operating mechanism about anywhere you like. A .750" rotor (or a dab larger) should be pretty easy to find.
I know that a .800" will fit right before the main slide, to keep with the expanding bore.
And I just so happen to have two lying around. Of course if you want to drop to .750" I have a couple of those as well. If you're interested send me an email. The main slide is pretty large, but if you could rig up a double slide - like Dan O did on that euphonium - you might be able to have some normal finger position. If you just dump the fourth into the slide you have to worry about where the linkage is going to be and how then are you going to tune on the fly if needed?
My goodness, Ian.... I'm sure glad you spotted that gross error. I meant to say the rotor should be just
BEFORE the main tuning slide. I feel like such an idiot!