How much needs to be cut from this BBb tuba?

[Michael Bush]

No, not to "cut it to CC"...

If A=335, this rebuilt-with-chinese-parts B&S 101 plays pretty well in tune. There's an obvious place to cut the main tuning slide. Approximately how much needs to come off so that it gets to 440 with the slide out around 3/4"?

Because of the way the rebuild was done, 2" would be a very convenient amount to take off, but obviously convenient isn't necessarily right...

[Michael Bush]

I assume that you mean A=435...and...

Yes.

If you want some extra room (your "being able to pull out at least 3/4" to achieve A=440") you might (??) want to find a way to remove approx. 4" from the instrument.

4" can be done. The slide would be obviously short-looking, but that's better than flat-playing. I think I'm going to try it. I've put stuff on tubas before. This will be the first time I've tried cutting on something that isn't junk purchased just to mess with.

Thanks to all for the advice.

[Michael Bush]

What about THIS piece...??

Unlike a tuning slide, it doesn't have to function mechanically after you're through altering it...

Good idea.

I've got the easy two inches out and taped together the intonation is much improved. I'll look at getting that piece off.

[Dan Schultz]

here's what I was told. If the horn is playing 20 cents flat with the slide all the way in, pull the slide out until it's 40 cents flat, measure how much you pulled, and then cut that amount

If it was me, I would cut more off, and have it so the horn plays 10 cents sharp with the slide all the way in (assuming you have that luxury with this slide)

also, keep in mind you might find each valve is a touch too long now, but maybe you'll dodge that bullet.

+1

[Michael Bush]

The reason the first 2" (really about 2.5", it turns out) was easy was that an improvised piece had been inserted to help the German and Chinese parts come together. By removing that piece and cutting the other leg, I was able to bring those parts together while also bringing the pitch back up to within the range of workability. The intonation is not as good as these tubas can be, but pretty good. I'm going to leave it be for now. Thanks for all the help.

[Ace]

Michael,

What mouthpiece are you using on that horn? The reason I'm asking is related to my experience years ago with my new MW 2145 CC. I plugged my trusty PT 50 into it and it played 20 cents or more flat. After a couple of rehearsals, the trombones in my orchestra "talked" with me about the problem. I then used the mouthpiece that MW packed with the horn---- a Melton 24 AW. Problem was solved and the trombonists became friendly again.

Ace

[Michael Bush]

This is the tuba in question, by the way. It's come a long way.

[Michael Bush]

Michael,

What mouthpiece are you using on that horn? The reason I'm asking is related to my experience years ago with my new MW 2145 CC. I plugged my trusty PT 50 into it and it played 20 cents or more flat. After a couple of rehearsals, the trombones in my orchestra "talked" with me about the problem. I then used the mouthpiece that MW packed with the horn---- a Melton 24 AW. Problem was solved and the trombonists became friendly again.

Ace

Funny thing... The mouthpiece in it at the moment is a Conn 2, because that was the only American shank mouthpiece at hand when I needed one. I have no idea what B&S put in the case. (I guess they put an American size receiver on it because it was aimed for American schools?)

EDIT: Turns out an RM2 works very nicely in it.

[Michael Bush]

Dang. Can I borrow some superglue?

[imperialbari]

Maybe too late to enter this thread, but the problem will come again.

To retune a tuba from 435Hz to 440Hz (with the tuning slide all way in) you have to change its current theoretical length (TL) from TL*1/1 to TL*435/440. The amount to cut will be TL*5/440 If you do the cutting at the tuning slide, each branch has to be cut half that length. If you want a certain amount of pull on your slide add that amount to the calculated cut.

The theoretical length, because the real length is shorter, as the bell flare has an effect of adding acoustical length to whatever tubing it is added to.

The theoretical length may be calculated precisely for a given temperature, but as the fraction is so small 18’ is good enough as a starting point for a BBb tuba.

(216"x5):(440x2) = 1.227"

Which is a little less than 5/4 of an inch.

If you want the 440Hz tuning with a slide pull of 3/4", you should cut each branch 2".

Klaus

[Michael Bush]

Interesting, Klaus.

For whatever reason, removing a total of a little less than 2 1/2" worked very well. (Maybe when I found 435 was about where it was, I was blowing tight and sharp?)

At any rate, I remain far more satisfied with the intonation of this tuba as it now is than as it was before. It's very close to 440 with the MTS out a bit. I could still push in on a cold day outside. The only issue the cut has introduced is the fourth valve slide has to be pulled out noticeably more now, but even it still has some more to give.

I am pleased with the result. And now I won't be embarrassed to pass it on to someone else when I eventually sell it (since sentimentality about what I played in high school isn't going to be enough reason to keep a tuba I never play around forever).

[imperialbari]

9’ are wrong. The 18’ that you mention are right. I was just thinking in the general C to Bb relation being 8 to 9, forgetting about being in the 16’ contrabass range.

Not to hide my error, but attempting to avoid more confusion, I have edited my previous posting, so that the calc hopefully is right now.

Klaus

[Michael Bush]

9" are wrong. The 18’ that you mention are right. I was just thinking in the general C to Bb relation being 8 to 9, forgetting about being in the 16’ contrabass range.

Not to hide my error, but attempting to avoid more confusion, I have edited my previous posting, so that the calc hopefully is right now.

Klaus

I've edited mine as well, but I think people can still follow the thought.

[ghmerrill]

I did this on my old Buescher Eb (the one in my current avatar) which also tuned to 435 (apparently that's what "low pitch" meant in this case). As I recall, I took off about 3/4" off each side of the main slide, but I'd have to check my records.

Then the valve slides needed to be addressed and I did the 1st and 3rd -- hoping I wouldn't need to do the second because there was almost no room to work on it.

After a couple of months of trying to live with that, I finally bit the bullet and cut the second as well, though it was painfully slow and careful work involving a small hack saw too I made, a Dremel, and file work.

The horn works well, and I tuned it a bit sharp (mostly for winter playing possibilities). Slow and careful wins the race. It took me at least two attempts to get it right on each slide section.

[ghmerrill]

Yeah. Like I say, I'd have to look up the final results since I did this. It was close to four years ago. It's quite possible that the initial cut was 3/4", but then I cut it again. I was being careful not to take off too much. I didn't view it as a "do it once and get it right" approach.

Also, determining the "exact pitch" that a horn plays at is difficult since it depends on several factors. Once I decided that the horn was playing high and mapped the pitches, it originally seemed to me that it was pitched at 438. But I couldn't get entirely consistent results, though I later decided it was closer to 435. I think there's necessarily some trial and error involved in this.

I was really unhappy at having to cut the 2nd valve slide, but the rest of the horn was behaving well and I just couldn't get the 2nd valve combinations at pitch without some degree of lipping.

[Michael Bush]

I took it to community band tonight. Played about half of a really simple part before going back to the CC. I'm just not smart enough to keep both sets of fingerings in my head at once. It sounds sweet though.

[Michael Bush]

Whelp. This tuba with the help of my own head has taught me a lesson I have learned too many times before: The quest for "perfection" is the enemy of "perfectly satisfactory", especially when you're a beginner just figgering stuff out.

It was fine. I undertook to make it better than fine and screwed up a part completely. So now I'm going to be calling around looking for parts or help or whatever.

[Michael Bush]

As you intuitively knew from experience, Joe, (while graciously holding out the possibility that it wasn't so) it was a slide tube. But it wasn't a problem of cutting off too much. I'll call you after while.

[Michael Bush]

As you intuitively knew from experience, Joe, (while graciously holding out the possibility that it wasn't so) it was a slide tube. But it wasn't a problem of cutting off too much. I'll call you after while.

If/when, could have have the o.d. of the tube available?

Yep. It will be a little while later in the day, though.