Issues with Eastman EBB354

[braymond21]

Hi everyone! I'm looking for some help from the more tuba-oriented techs here. Sorry for the long post, there's a bit of explaining to do.

To preface, I'm a well-versed repair tech myself but I'm at my wits end with this thing so I'm hoping someone has more experience with this model and can give me some pointers.

Here's the situation: I have a like-new condition Eastman EBB354 BBb tuba and it doesn't slot well in almost any register and is just generally difficult to play. If I get my embouchure and air exactly correct at the dynamic the horn wants to play, I can get a good sound, but it's quite a bit of work. I've had two other players test it, one of which owns the same model, and they both said there was something wrong with mine and it felt terrible to play.

Here's what I've tried so far:
I started by checking for any cracks in the tubing. Multiple visual inspections turned up nothing and all the solder joints I could see looked solid.
Next, I checked the valve alignment with my borescope and everything looked to be lining up just fine.
After that, I tested every feasible piece of tubing with my magnahelic. I was able to test all the slides, the lead pipe, and every tubing run that comes off of the valve section, except for the one that goes to the bell, since it's too much tubing for my little machine to be useful. Everything sealed perfectly so no issues there.

My next idea would be to tear apart the horn, and possibly just rebuild it, but for something that's nearly $5k and almost new, I'm not really inclined to do that.

I've heard great things about these horns and have played a few good examples of them in the past, so I'm hoping this one can be just as good as I'd imagined! I also can't resell it and get something different snce it's not playing as well as I think it should.

Any thoughts? Comments? Questions? It's been driving me crazy so any suggestions are appreciated!

[arpthark]

Could it be possible there is a packing peanut or something wedged in a tube? Have you flushed it out?

[braymond21]

I'm pretty sure I gave it a cleaning when I first got it, but that's a good idea. I'll give it another check, it's definitely possible there's something in there

[OhioTubaGuy]

Is it bad on all valve combinations and partials?
Similar to the packing peanuts idea, it sounds like something silly, stuck someplace silly.