Constructing a 6/4 Eb?

[Heliconer]

So here's the idea...

Take a Conn Monster Eb, throw in a 4v .863 rotary valve set. Has there even been such a large Eb made? Or is this doomed to be terrible?

Basically, I need to be disuaded before I get any further.

[Heliconer]

Well. That was exactly what I needed to hear. I knew that the fast taper is one of the largest problems of these horns, so the rest of that was just tasty tasy gravy.

Is there much success in turinng these into CC by adding a length of straight tubing before the dogleg and continuing that into the valve set?

[DouglasJB]

What is the largest body you could use for an Eb and still have a good horn?

[roweenie]

The elephant nailed this topic perfectly, with not much more to add

Generally, what bore you use on a project is determined by the bore size of the small end of the dogleg, where it meets the larger leg of the MTS.

For example - on the most recent York monster E flat (factory side-action) I worked on, the bore at the above mentioned point was a hair smaller than .734 (all measurements I give are I.D.), and the valve set bore was .656. At first, I experimented with a 19mm (.748) valve, a King MTS (which is .750 at the dogleg side) and a .687 King valve set, but I found that the usual "trouble notes" (low B flat, A, and A natural) were unacceptable to me. I then placed an 18.5 mm (.728) rotary valve there, used the original York MTS, and a Conn 4J .656 bore set, and this combination dialed those notes in considerably better than with the first configuration I used.

What does all this mean? I suspect the folks that designed these old horns knew more than we give them credit for, and that the specs they used were not determined by accident.

As to making a monster E flat into a CC, best to pair the bell and bottom bow to the branches of an old-style King 2340/1, and throw the original branches on the scrap heap. Personally, I never had the taste for the CB-50, but that's just me, I guess.....