Besson 3V comp leadpipe and receiver length?

[MusicSmiths]

In the past - someone changed out the Besson euro-shank receiver on my horn and put in a homemade receiver made out of a piece of pipe and a King Sousaphone receiver. This was all well and wonderful for converting the horn to an American shank standard, but they made it too short. Leastwise it plays much better if the mouthpiece is another 7/16ths to 11/16ths of an inch further out of the receiver. I used electrical and teflon tape as a shim to make this discovery. In my conversations with Buffet they said that all the information on this horn was lost/thrown away/burnt..., or whatever when Besson went out of business in the early '80s(?). So...

My technician has found an American shank tuba receiver in his parts bin and we are in the process of figuring out how long it should be since it doesn't fit on the leadpipe quite like an original Besson tuba receiver would and the existing homemade receiver isn't a good reference. At the moment things are now too long and the horn plays flat. Does anyone here know or perhaps be willing to measure the distance from the 1st valve casing to the end of the receiver on an unadulterated Besson 3v comp? And since I'm not a tech - would that be down the center-line of the pipe or something else? Are there any other objective ways to determine what the length should be without introducing the variability of my playing prowess - or lack thereof? Something like in the old days when you adjusted a carburator's idle jets with a combination of a vacuum gauge and tachometer?

Just for grins I had another meandering thought - since the original receiver is no longer around and to increase the number of red-flags on this horn for any future resale value it may ever have - I could install an AGR. Does anyone know how much length differential a typical tuba AGR provides? I looked at the Dillon patent information and it didn't say. Based on my crude empirical experiments it appears there's a "sweet spot" range of length - say .25 to .5 inch or so that yields similar playing characteristics. Any thoughts?

David

[TheGoyWonder]

2.5" end to end on the receiver
Very approximately 16.5" leadpipe length from hitting 1st valve casing to end of receiver.
Adjustable is better than finding a needle in a haystack match, I don't think there's any master list of receiver lengths, opening diameters, typical insertion depth, ect.

Bessons do need to be pushed in almost all the way, so if you tweak it a lil flat you might have trouble.
Maybe find a receiver/mouthpiece combo that plays well then fix the pitch, instead of trying to solve it all at once.

[TheGoyWonder]

Also the British shank mouthpieces have shorter shanks than American, so maybe 2.25" receiver is what you actually want.

[MusicSmiths]

Cool! Thank you for finding this out. I have a Denis Wick 1 and I had noticed, but not really thought about the implications of the shorter taper on the shank.

David

[TheGoyWonder]

Huh, I have the main out very little to none, valves 1-3 jammed all the way in...and 4th as far out as it can be.

Bloke, tell me if you cook up a good 1st valve pull! Would it be like the 3rd valve on a King 2280 euphonium? Reverse part of the slide pull so there is a fat part to mount a grip and a spring housing, run a spring up around a brace. Put O-rings where it clanks.
That would also cure the usefulness of the YBB-321 by giving it a good 1-4 low Eb (124 is nowhere close on that model)

[TheGoyWonder]

Ah yeah because your left hand is occupied in the 3+1. But not in the 3v or YBB-321, it could be sprung like King 2280 where the only moving part is the slide itself.

[MusicSmiths]

Thought everyone might like to see the results. The distance from the outside of the first valve case to the end of the receiver is now 16 inches. I've attached some pictures of the before and after along with a picture that shows where the valve and main tuning slides ended up. Thanks all around!

[MusicSmiths]

And the final picture - the new receiver.