Today was the first time since I started this thread that I had enough free time to look at this.
First off, the introduction of the twisties in a rotary valve section could have been the source of some of the pitch issues. I know for a fact that a machine by itself can be just fine so far as intonation and response go, as can the bugle, but WHERE they are placed can destroy both intonation and response. I do not understand how to figure this out beyond simple trial and error, though.
Today I started the trial and error process. Or — more accurately — I started the trial-error-
retrial process.
And I made some interesting observations.
First of all, let me say again that
this bugle plays *very* well in tune with a stick of straight pipe in place of the valve section. If this is the "stinky" tuba that
@bloke harvested the valves from, the bugle itself is not the culprit.
Secondly, I taped my homebrew Olds .656" rotor set between the leadpipe and MTS. The intonation SUCKED. I tried about ten mouthpieces and the tendencies were pretty much the same, regardless. Okay, so now I know for certain that this tuba very well
could be the same one that Joe disliked so much. It sort of reeked; this was a big disappointment for me.
I only have four rotary valves in my homemade Olds stack, so there was a big gap that I used a spacer to fill, and it occurred to me that maybe the issue is in the middle of the valves, so that two valves, a gap, and two more might correct the change the valves introduced. Of course, I am far too lazy to take the Olds rotary valves apart to see whether this is the case. What if first I just slide the whole stack down to the MTS and put the spacer on the leadpipe end?
Instant improvement, but the 3rd partial C was still very high.
In a further attempt to avoid doing any actual work, I decided to dink around with a different leadpipe. I still own the much-hated leadpipe off of my erstwhile 1972 Mirafone 180 F tuba. (I removed that leadpipe back in December of 1997. I throw
nothing away, heh, heh, heh…) I remembered that it was just too tight sounding for that tuba, but the intonation was better than the 183 leadpipe I bent to fit the horn.
By this time I had homed in on one mouthpiece that really stood out with this bugle, and using it and the old 180 leadpipe with the Olds rotors the horn plays very well in tune and the sound and response are both excellent.
I plan to temporarily install the Olds valves with the old Mirafone leadpipe sometime soon. I will lock the rotors in place and tape over the slide ports. I do not need a spacer as the M'fone pipe fits best in a location where no spacer would be needed. It places the mouthpiece stupid-low, but the jacked-up MW leadpipe location is still too low for me, so I would have to place the horn on a "euph dude" (a rolled bath towel) anyway, so why not?
I used the tiny receiver on my Kurath because the small end of the leadpipe is *that* small (and the 6/4 F tuba benefits from this a great deal, I believe) so I need to buy a new one from Miraphone. I have something that will function until then, but I do not like it. Anyway, I have all the stuff needed to temporarily install all this junk onto this junky bugle, and then I can start fiddling with some variables to see whether this can be made into a really good instrument. If so I will drop the funds needed for new Miraphone valves and machine parts. I already have the levers and rack and linkages. I have all the needed inner and outer slide tubing.
However, after all this, I will have a kickass little F tuba — BUT WITH ONLY FOUR VALVES.
Esto no está bien.
My personal preference is to have four pistons with a tapered MTS crook and the 5th valve on the far side of that crook so that it is larger than the piston bore. (I like 4th to be the same as the other pistons, too, but that is another can of worms to be opened some other time.) On this tuba, it just so happens that the dogleg is shaped in a manner that would allow a fairly simple insertion of a pair of 186 rotors. This will place them below the plane of the other rotors and allow for the linkage systems to be fitted so that nothing interferes. I will have to remove the links before I could remove the four main rotors, but making the 5th/6th section removable to allow for easier cleaning and maintenance would not be all that hard now that I have done this on a few tubas.
Also, doing this just as I did with my larger Kurath is added cost, but not so much so. I would use a custom-ported and drilled 186-sized rotor with a larger exit port, into the next size larger rotary valve, which will be similar, including a larger exit port. After some work with the old calipers, I know that this will be an almost exact fit in the space. A few small adjustments will have to be made, but essentially it will be much easier to make work than the nightmare I have on the Kurath. (Which works quite well, by the way.)
So once I have the needed receiver I can start work on this. I have all the parts bagged and in a container, ready to go.
The 1972 Mirafone leadpipe really saved the day!
As far as the Olds rotors go, they still are not ready for Prime Time, so I will also buy them new from Miraphone. However, due to the cost, I will have to put that off until I know for certain that this will be worthwhile, so the Olds valves will be what I use for the initial setup and testing. If/when I get the needed valves from Miraphone, I will use two 17.95 mm and two 18.73 mm valves as this will do a near-perfect job of connecting the slightly smaller Mirafone leadpipe to the slightly larger Meinl-Weston MTS. I can buy all the needed crooks and runners from 180, 184, and 185 stock. All I will have to do is measure and cut all the inner and outer slide legs and the ferrules. I also need the three posts to which the lever rack mounts. But that is pretty much it.
This mess could become my next F tuba…
Four 1968 Olds Ultratone contrabass bugle rotors, a 1972 Mirafone 180 leadpipe, two 1977 Mirafone rotors, and a 1982 Marcinkiewicz mouthpiece on a Meinl-Weston bugle?
The old Mirafone rolled and seamed leadpipe is in all ways nicer than the cheaper, hydro-formed, two-piece stock MW one. It is also noticeably smaller despite being just about the same length.
The stock pipe is on top. The Mirafone pipe fits inside it, albeit very snugly.
Marcinkiewicz "N 15" or "N 1S"? It is 100% certainly stamped with an "S" and not a "5", but it could be an accident. Did he even make an "N 1S"?