Is valve compression an indicator of valve condition?

[improver]

Is your valve compression tell you if your valves need replatinng? How do you look and recognize valve wear? How do you know if valves have been replated?

[yourbrass]

One way is to note the response of the horn in the low register. If it's uncentered and "airy" down there, the valves are probably pretty loose.

Valve refitting is not cheap and will take months to get done, so you have to consider whether the horn is worth the money sunk into it and whether you want to be without it for a while.

I tell people it's usually three months' turnaround.
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ACB MV3C /ACB A1/26 backbore
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[Manuel de los Campos]

If the fit of the piston (valve) in the cylinder (valve machine) is exceeding the tolerances air will leak away through the space between the piston and the cylinder.
This results to poor performance; the response of the wind instrument will be frustrated that much (depends on the amount of wear of course) that even a first class pro horn will perform like a poor made Bessons & Co. made somewhere in India. I once posessed a worn out Olds Super that I send it over to Charly Melk. I got it back and the trumpet played like a new one, very very good.
Very good compression though does not nessecary lead to good performing valves: The new boucht Franz Straub trumpet with Bauernfeind valve machine had an excellent compression but the 2nd valve kept on frustrating me. I even send it back to Franz and got the trumpet back with.... a dragging 2nd valve.
The valve machine of trumpet I parked at the house of my parents in law in Swiss never let me down: a low end Chineese clunker named Melody Maker Foreign Make: they never drag, look like **** and have 100% compression after I oiled them with AllSyn syntatic oil...

If your instrument performs well (both play wise as technical) there is no reason to send it to whoever for a valve job. Oil the machine regular, clean the horn in time and enjoy making music
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Technology alone is a poor substitute for experience. (Richard Sachs)

[trompette229]

There isn't a fool proof way to visually look for low compression. Valves that look great may leak and those that look spotty and patchy may be just fine.

Short of taking your horn to a good brass tech who can run a compression test, the old school DIY version is to simply pull out each of the 1st, 2nd, 3rd slides and listen for a pop. If they pull too easily and don't "pop" you MAY have a leaking piston/casing. I say may as the slides themselves could be partially to blame but it is more often the valves. There are those that will tell you that pulling the slides will somehow damage the horn, this simply isn't true.

As far as knowing wether or not a horn has had it's valves done in the past, try finding a pic of the valves of your model horn. Most pro horns (not Getzen) will have silverish pistons (monel) with brass inserts in the ports. If the pistons and ports are all silver/grey, they may have been replated as more often than not the ports aren't plugged when replating (usually with nickel).

Keep in mind at some point you'll have. to take the horn to a good tech at some point in the process so if you suspect your horn is not playing optimally the tech might be the best initial step. Good luck

[JayKosta]

Part of the concern with 'low compression' or 'leaky valves' is that the vibrating column of air can take unwanted paths into and through tubing that should not be in-use with the fingering that is used. This is sometimes called 'jug handle' leaks / leakage. Those leaks alter the tubing length and can result in harmonics being created that do not match those of the chosen fingering - leading to the sound being altered or 'fuzzy', and change how the notes 'slot'.

If trouble is suspected, the first action should be to verify that poor 'valve alignment' is not the cause. If alignment is good and the sound is fuzzy, or 'valve slurs' are 'really smooth', then leakage might be the cause.

Water dripping out the bottom of the valve casing is another clue that there is leakage.

When actually playing, the air pressure inside the instrument is not really an issue - the concern is the path of the vibrating air column.
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.

[Manuel de los Campos]

[Halflip]

[jeirvine]

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[adagiotrumpet]