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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby pwhitaker » Fri Nov 03, 2017 1:38 pm

1 fewer port per valve in the non-comps.
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby Mark Finley » Fri Nov 03, 2017 2:38 pm

Obviously that makes the valve shorter and lighter, but wouldn't necessarily mean the stroke is shorter, except on the King's It Is
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby Donn » Fri Nov 03, 2017 2:56 pm

Mark Finley wrote:King horns have a shorter stroke than compensating euphoniums. Not sure why


The stroke is port size + space between ports, right? So one or both of those would have to account for it.
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby Mark Finley » Fri Nov 03, 2017 3:06 pm

Yes but I'm not sure why King can make their valves with a shorter stroke but compensating euphoniums can't or don't
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby windshieldbug » Sat Nov 04, 2017 9:36 am

My guess is that we Yanks have all the patents on port size changes, which you'd need for ANY shorter strokes...
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby bloke » Sat Nov 04, 2017 3:41 pm

Regardless of the stroke-length of your valve, never agree to an organ intro.
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby Rick F » Sat Nov 04, 2017 4:01 pm

Mark Finley wrote:Yes but I'm not sure why King can make their valves with a shorter stroke but compensating euphoniums can't or don't

The Miraphone 5050 has a bit shorter action. I measured it at 3/4" (19.05mm) vs my Yamaha 641 which is 7/8" (22.225mm). That's 1/8" (3.175mm) shorter action. Not sure how the German engineers do that with a bore of .610" (15.494mm) through the main valve section of the M5050. I suspect it has to do with the bumps seen inside the ports of the pistons which allow a closer overlap of the tubing that connect the ports.

not a valve from M5050 - just image ref.
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Miraphone 5050 - Warburton (Brandon Jones)
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Re: FOR BAND DIRECTORS: compensating vs. non-compensating

Postby bloke » Sun Nov 05, 2017 11:01 am

"large piston tuba-wise..."

The Yamaha .728" bore tuba piston porting design (which seems to have been copied in Brazil and in China) is just about the most distortion-free porting I've seen, and the stroke is short as well.

Putting those nearly distortion-free (and bonus: short-stroke) .728" bore ported pistons on a .748" bore instrument would still offer 95% of the area (inside the ports) of (comparing "perfect" to "perfect") .748" bore ported pistons. I'd wager that the distortions and compromises found in most of the .748" bore pistons take away more than 5% of the total area (again: were the porting "perfect").

Moving, now, from theoretical numbers to real application, I would think that the Yamaha ~design~ .728" bore pistons would play a .748"/.750" bore tuba just fine -likely (??) with more conserved/preserved bore area than most all other pistons or rotors of .748" bore.
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