I'm re-furbishing an old French three valve trumpet. The valves have been mixed up. There are no numbers on them, unlike modern trumpet valves. Is there a simple way to ascertain which valve goes into which aperture?

  • 1
    Are they piston or rotary valves?
    – phoog
    Sep 12, 2023 at 7:15
  • @Phoog - ordinary pistons.
    – Tim
    Sep 12, 2023 at 7:24

4 Answers 4


Take all the valves out. Then place one of the valves in the third valve casing. Turn it until the valve guide "clicks" then blow (gently!) into the horn. If air goes through, then depress the valve and blow (gently!) again. If air goes through, you have the right valve in the third casing. If air doesn't go through, try the next valve in the third casing...

Once you've got the third valve correct, leave that valve installed and try one of the remaining valves in the second casing. You do them in this order because the leadpipe goes to the third valve and the bell pipe comes out of the first valve.

Be sure to blow gently so that you don't injure yourself if the air stops.

  • 6
    I was going to say this as a joke! I.e., "play the horn and if the wrong notes come out you goofed" . Congrats on being polite about it Sep 12, 2023 at 17:06
  • Exactly this. I had to use it myself some years ago at a brass band rehearsal as my section mate's wife had cleaned his tuba and just stuck the valves back in any old how! The night before a contest as well! Being a traditional British 4 valve Eb tuba with 3 on top and one on the side, the 4th valve was easy, then it was just a case of getting the 1st valve correct, then the 2nd.
    – yorkie
    Sep 15, 2023 at 19:13

I would first try to align the holes in the valve body with the tubes entering the valve housing. If I recall correctly I've done this successfully with piston valves in the past, but it would have been the fairly distant past so my recollection could be faulty.

If that doesn't work for some reason, you can just try all possible combinations until you find the right one. There are only six possibilities; it shouldn't take too long.


The simplest way is to address the second (middle) valve first. Take off the short tube attached to the trumpet (the one which lowers the pitch by one semitone), so you can see the holes in each of the valves as they are put in, in turn. Only one will have holes which line up with those in the trumpet pipework, when depressed. That, then, will be the appropriate no.2 valve.

Then, it's 50:50 for the other two!

  • This, of course, assumes that (a) it is possible to get the tube off, and (b) once off it's possible to see the valve holes. Of the instruments I could immediately lay my hands on the success rate was 50:50, which is not bad :)
    – psmears
    Sep 12, 2023 at 15:54
  • @psmears - the tube ought to be removable - I'm refurbishing, and if not, the job's not a good'un. Yes, it's quite possible to see the valve holes, hence the answer. Point is, it's only possible to see the holes on valve two.
    – Tim
    Sep 12, 2023 at 16:45
  • Yeah - on one of the instruments I looked at just now, the middle tube is mounted at an oblique angle, so it's unclear whether removing it would give a clear enough view of the holes. Unfortunately it's also wedged on tight (and I don't have time to unwedge it), so I wasn't able to actually check...
    – psmears
    Sep 12, 2023 at 17:13
  • @psmears - all three should be easily removed. When that one in particular is removed, one can see the holes line up. Not so with the other two.
    – Tim
    Sep 12, 2023 at 18:31
  • "Should"? Yes! (at least in this case - wouldn't surprise me to find a low-quality instrument with them welded on). Just needs some TLC that I don't have time for. "See the holes"? In this case I'm not sure, because there is a (designed in, deliberate) bend in the tubing between the joint with the valve and where the loop slides off. (On the other instrument I looked at there's no such bend; the tubing slid off easily and the valve holes were clearly visible. My point is that there's a surprising amount of variation in instrument design and quality, which may make some approaches less useful.)
    – psmears
    Sep 12, 2023 at 18:48

There's only six possible combinations! Just try. Put one of the valves into the first housing. Blow. If air doesn't get through with the valve both up and down try one of the other two. Then the next housing...

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