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Thread: Vented valves pistons

  1. #1
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    Vented valves pistons

    I noticed on this forum that the last buyers of Adams euphoniums ordered their horns with pistons with a vent valves: I wandered what advantages you have with this device; you only avoid the "flop"when you remove the slides, or you do they eliminate those little noises due to the residual air when the pistons are activated?
    I intrigued, I tried do drill the exhaust holes on the pistons of my Besson Prestige: the result is excellent. more quiet valves and it is no longer necessary to depress the pistons when removing the slides.


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    2007 Besson Prestige 2052, 3D+ K&G mouthpiece; JP373 baritone, 4B modified K&G mouthpiece; Bach 42GO trombone, T4C K&G mouthpiece; 1973 Besson New Standard 3 compensated valves, 3D+ K&G modified mouthpiece; Wessex French C tuba, 3D+ K&G modified mouthpiece.

  2. Hi Franz, I am impressed that you drilled the holesyourself, I also play a 2052 prestige and would love to eliminate the littlepopping noises when the valves are activated during playing is this what youmean when you say “eliminatethose little noises due to the residual air when the pistons are activated”


  3. #3
    I ordered mine vented for both reasons. The hole you put in your piston looks just a little larger than the ones Adams put in mine. With mine, I find that can get a little clogged if I don't clean the hole now and then.
    Dave Werden (ASCAP)
    Euphonium Soloist, U.S. Coast Guard Band, retired
    Adams Artist (Adams E3)
    Alliance Mouthpiece (DC3)
    YouTube: dwerden
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  4. #4
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    In reality it is not a difficult job,you just have to pay attention,when you drill the hole, not to puncture the passage of the air below: to do this you need to take a drill with a stopper, so as to allow the drill bit to drill only the stainless steel wall of the piston. I made the hole of the same diameter as the one on the bottom of the piston, i.e 3mm.
    2007 Besson Prestige 2052, 3D+ K&G mouthpiece; JP373 baritone, 4B modified K&G mouthpiece; Bach 42GO trombone, T4C K&G mouthpiece; 1973 Besson New Standard 3 compensated valves, 3D+ K&G modified mouthpiece; Wessex French C tuba, 3D+ K&G modified mouthpiece.

  5. #5
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    Quote Originally Posted by franz View Post
    In reality it is not a difficult job,you just have to pay attention,when you drill the hole, not to puncture the passage of the air below: to do this you need to take a drill with a stopper, so as to allow the drill bit to drill only the stainless steel wall of the piston. I made the hole of the same diameter as the one on the bottom of the piston, i.e 3mm.
    I don't use a drill stopper/collar for this -- a bit afraid of marring the surface of the piston, and I do have a lot of experience in drilling thin sheet metal. If you've done this sort of thing before, you can feel when the drill goes through the the piston wall. Of course, I use a drill press. Using a hand drill, it's a bit more difficult to have the necessary control and sensitivity to not go too far, difficult to avoid the bit "skipping"/sliding on an unpunched curved surface (and you sure don't want to center-punch that piston wall!), and a lot easier to slip and ruin your piston.

    3mm strikes me as an excessively large hole for a piston vent, at least on a euphonium (almost twice as large a diameter as is common). In general a much smaller hole is drilled -- more on the order of 1/16" (1.6 mm) or 5/64" (2 mm). If the 3mm works for you, then it works for you. But people should keep in mind that the point of the piston vent in the sidewall is to vent AIR while the point of the vent in the bottom of the piston is in part to allow accumulated water to drain out, and it also has to vent MORE air in less time than the wall vent does. Too large a vent hole could result in giving you some really airy slurs. Just beware of going a little far with this.
    Gary Merrill
    Wessex EEb Bass tuba (DW 3XL or 2XL)
    Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
    Amati Oval Euph (DE 104, Euph J, J6 euph)
    1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
    Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
    1947 Olds "Standard" trombone (Olds #3)

  6. #6
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    What do you mean by " too large a vent hole could result in giving you some really airy slurs "?
    2007 Besson Prestige 2052, 3D+ K&G mouthpiece; JP373 baritone, 4B modified K&G mouthpiece; Bach 42GO trombone, T4C K&G mouthpiece; 1973 Besson New Standard 3 compensated valves, 3D+ K&G modified mouthpiece; Wessex French C tuba, 3D+ K&G modified mouthpiece.

  7. #7
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    Well, when you move the vented piston, there's a short duration when the vent hole "overlaps" two runs of tubing. This is what makes slurring with a vented piston "smoother" and eliminates a "pop" that euphonium players seem to remark on quite a bit. What this means is that air is "leaking" through the vent. But it doesn't leak anywhere "bad" and it leaks only for an instant. However, obviously if you make the hole "too big", then there will come a point where the leaking will be noticeable since it takes longer for the "hole" to pass from one position to another and it will "overlap" two chambers for a longer time. This phenomenon has been referred to as a "transitional leak". You'll find it described here: http://forums.chisham.com/viewtopic....tart=20#p85079.

    I confess that I don't really know what the facts are on what is "too big" a hole and what the degree of the effects of this are likely to be, but I'd worry about using a vent hole that was bigger than necessary to do the venting job and that consequently would perhaps invite some problems with tone or sound quality. Notice that in the link I just provided, again the size of the vent hole (in that case ON A TUBA) is 1/16", or roughly 1.6 mm.

    The area of a 1.6 mm diameter (0.8 mm radius)hole is approximately 2 sq. mm. The area of a 3 mm diameter (1.5 mm radius) hole is approximately 7 sq mm -- or 3.5 times the area of the smaller hole. So by moving from the usual recommended 1/16" (1.6 mm) diameter vent hole to a 3 mm vent hole, you've increased the hole size (area through which the air moves) to more than 3 times the size of the smaller (recommended) hole.

    This problem becomes even more of an issue in venting rotary valves when there is failure on the player's part to open/close the valve completely (or when there's an alignment issue). Search for "vented valves" on TubeNet and you'll see more discussions of this sort of thing.
    Last edited by ghmerrill; 12-10-2017 at 09:26 PM. Reason: Clarified degree of increase of hole area when using 3 mm diameter hole.
    Gary Merrill
    Wessex EEb Bass tuba (DW 3XL or 2XL)
    Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
    Amati Oval Euph (DE 104, Euph J, J6 euph)
    1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
    Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
    1947 Olds "Standard" trombone (Olds #3)

  8. #8
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    I understood the concept. Looking at the discussion on TubeNet there are discordant opinions on the vent holes. With 3 mm holes I have made I do not feel any problem: when the pistons are pressed they move too fast to feel a possible air leak through the vent and have the advantage of no getting clogged. Overall i'm pleased to have done them.
    2007 Besson Prestige 2052, 3D+ K&G mouthpiece; JP373 baritone, 4B modified K&G mouthpiece; Bach 42GO trombone, T4C K&G mouthpiece; 1973 Besson New Standard 3 compensated valves, 3D+ K&G modified mouthpiece; Wessex French C tuba, 3D+ K&G modified mouthpiece.

  9. #9
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    Quote Originally Posted by franz View Post
    I understood the concept. Looking at the discussion on TubeNet there are discordant opinions on the vent holes. With 3 mm holes I have made I do not feel any problem: when the pistons are pressed they move too fast to feel a possible air leak through the vent and have the advantage of no getting clogged. Overall i'm pleased to have done them.
    As I said, if it worked for you, then it worked for you. However, for others contemplating this, it would be wiser to start with a smaller hole and see if that works. While you can always make the hole larger, making a too-large hole smaller requires skills well outside the scope of an amateur metalsmith, and will result in an imperfect solution in any case. Just a word of caution.
    Gary Merrill
    Wessex EEb Bass tuba (DW 3XL or 2XL)
    Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
    Amati Oval Euph (DE 104, Euph J, J6 euph)
    1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
    Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
    1947 Olds "Standard" trombone (Olds #3)

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