maximizing the Olds O-99-4 "eBay treasure" BBb tubas

[roweenie]

Resurrecting this excellent thread with a question:

Does the unusually long 3rd valve circuit apply to only the "Olds" badged "curly-cue" horns, or does it also apply to the Conn 4J "open-wrap" in BBb? I just measured the one (4J) I've got here, and it computes in at an extremely long 46 3/4". Does that length seem consistent with the O-99-4?

Or, in lieu of that, has anyone had any experience in cutting down the 3rd valve circuit of a Conn 4J? How much did you eventually remove?
(I don't think I've ever seen a BBb tuba with a 3rd valve circuit that long - - -)

(The 1st valve circuit is a more realistic 27", and the 2nd is 13.25" - maybe one of the board's scientists has some input as to what the length of the 3rd valve circuit approximately should be....)

[TheGoyWonder]

had this done and it works. Moving that 3rd valve brace and eliminating the brace to main tuning slide seem to have no ill effects.

Has anybody mentioned yet - DON'T CUT the long 3rd valve inner slides, swap them with the 4th valve inner slides! Because 4th valve is barely, barely long enough as is.

[roweenie]

I like mine a lot (actually a 4J) - especially after the tweaks, and adding a 5th valve:



There was plenty of room (lots of cylindrical tubing on the large side of the MTS), so it was a relatively easy job, too.

[roweenie]

nice work

Greatly appreciated, bloke

I forgot to add that the rotor is 17.5 mm, roughly the same size as King .687 tubing, so all the components were readily available.