Valve compression check for used horns?

Discussion in 'Horns' started by Oldgreentoad, Aug 30, 2005.

  1. Oldgreentoad

    Oldgreentoad New Friend

    Aug 30, 2005
    Portland, OR
    Hello guys and gals. I am 40 year old beginner who has finally decided to make time for myself and take up the horn. First order of business is going to be finding a good used horn. Could someone tell me the best way to check the valves for compression when inspecting a used horn. Thanks for the information.

  2. W Scott

    W Scott Piano User

    Dec 8, 2003
    Carson City, NV.
    Best way? Send them off to a good tech and have them mic the valves.

    Other ways:

    1. Check for a 'pop' after you pump the valves and pull a slide out. Still, one of my horns had this pop and the valves were badly shot.

    2. Problems with intonation and slotting of the notes. An experienced player can catch this pretty quick---especially the slotting of the notes which will be really bad. You'll line up for a middle C and hit D or Bb instead.

    3. Pull the slides and do a visual inspection to see how the valve ports line up with the slides. Use a small penlight to see how things line up.

    4. Another way to tell is play the horn side by side with another horn that you know is aligned properly and is a similar model. I bought a 1947 Conn 22B that I play tested against my Constellation that had been PVA'ed at the Brass Bow. The 22B played every bit as good and didn't need any sort of alignment then.

    I hope this helps.............
  3. TheLawTalkingGuy

    TheLawTalkingGuy New Friend

    Feb 25, 2005
    Halifax, Nova Scotia
    I would agree with W Scott that the "pop" can be really misleading, since it's hard to measure. I got a good pop on an older horn I tried out some time ago, and all three valves leaked like crazy!

    My repair guy showed me how to get a better (but still inexact) idea of compression:

    Depress any (one) valve
    Remove the corresponding tuning slide
    Cover one side of the tuning slide port completely - the meaty part of a fingertip works well
    Blow air through the horn forcefully
    If air is rushing out the valve port, cover the other port(!)
    The amount of resistance you feel when the (proper!) valve port is blocked is roughly proportional to the compression, with any "exhaust"suggesting a leak.

    Ideally, you shouldn't be able to blow through the horn at all, since the seal would be airtight. Of course, there could be many other explanations for leaks - pinholes, thinning of (overbuffed!) metal, invisible damage, leaking water keys/corks, etc.
    Repeat with the other two valves.
  4. Oldgreentoad

    Oldgreentoad New Friend

    Aug 30, 2005
    Portland, OR
    Thanks for the great information guys! Remind me what life was like before the internet.

  5. Robert Rowe

    Robert Rowe Mezzo Piano User

    Dec 24, 2004
    Yo, toad-dude !

    Welcome to TrumpetMaster.

    I will agree with the post submitted by TheLawTalkingGuy ... (whoever you are, I hope to Heaven you are not a dreaded lawyer).
    There is useful information in it. However; a cursory inspection by a NAPBIRT technician is the best way to go, if your background with horns isn't that deep.

    Robert Rowe
  6. TheLawTalkingGuy

    TheLawTalkingGuy New Friend

    Feb 25, 2005
    Halifax, Nova Scotia
    Excellent advice, Robert (as usual). I have a pro technician look at anything I plan to sink any money into, with the possible exception of eBay "deals" ;-) I am mostly a lurker here and on TH (better to be silent and be thought a fool, etc.) but I thought this compression tip was a neat trick.

    BTW, I am a "dreaded lawyer", but I offer the following in my favour:
    1. I'm a trumpet player!
    2. I actually work for a living - I'm neither an ambulance chaser like Lionel Hutz (thus the nickname) or a super rich corporate lawyer. I'm in between, toiling away at government wages(!) as counsel for the local Children's Aid Society.
    3. I'm a trumpet player!
    4. Before law school, I did ten years in the Navy (including almost a year in DESERT STORM/"Gulf War I - the prequel") and I continue to serve as a Naval Reservist.
    5. I'm a trumpet player!

    So..... (some) lawyers are people, too!
  7. brian moon

    brian moon Forte User

    Before testing compression dry the valves and casings off. All tests are more accurate then. Then you will know if the the seller has applied thick stuff to the valves to seal them up. You should play the horn with dry valves, casings and slides. Just open notes is ok, I wouldn't want someone playing Flight of the Bumblebee on my horn with no oil either. Then oil and grease. Even the tightest horn in the world will play better when lubed but if the valves or slides are toast you will really know the difference.

    Try to move the valve stem sideways from the finger button while holding the horn firmly . If there is a lot of play or a "tick" that can be an indicator of worn valves. That is difficult to explain cuz I have always just demonstrated in the past but I hope you get the idea.

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