Converting a Bb trumpet into a C horn

Discussion in 'Trumpet Discussion' started by Blind Bruce, Jul 7, 2009.

  1. Blind Bruce

    Blind Bruce Pianissimo User

    Apr 17, 2009
    Winnipeg Canada
    I am not too educated on the philosophy of keys but I am just wondering what changes need to be made to a horn to make it operate in the key of C from Bb?
  2. Dale Proctor

    Dale Proctor Utimate User

    Jul 20, 2006
    Heart of Dixie
    Shorten all the slides and put a C leadpipe and bell on it...:roll:
  3. rowuk

    rowuk Moderator Staff Member

    Jun 18, 2006
    Th biggest difference is the length of the instrument, slides and the leadpipe. It is possible to cut down everything, but it will be a terrible player without a real C leadpipe. Even with one, the intonation may not be that good.

    I would only attempt this with a real cheap horn. Transposition is not that hard and has many advantages.
  4. Dr. Zink

    Dr. Zink Pianissimo User

    Feb 8, 2007
    North Coast US
    Not necessarily. Thirty years ago putting Bb leadpipes on C trumpets was all the rage. I did it my self to surprisingly good effect.

    As for bells - I've seen olds conversions that were surprisingly good players.

    Start with shortening the main slide, then a bit off the bell tail if you have to. Do use a junker horn though.

    A fun project act any rate.

  5. samdaman

    samdaman Pianissimo User

    Jun 15, 2006
    Baltimore, MD
    Converting a Bb into a C....

    1)Take your Bb to Dillon's
    2)Trade it in on a C Trumpet
    3)Walk out of Dillon's with the C

    Conversion complete!!!!
    Phil Kersh likes this.
  6. Bob Grier

    Bob Grier Forte User

    May 4, 2007
    Greensboro, NC
    it could be fun with a junker but not with a nice horn. All the slides would need to be shortened along with the bell to very precise lengths. you can't shorten the leadpipe proper without screwing it up
  7. Phil Kersh

    Phil Kersh Pianissimo User

    Feb 28, 2008
    Provo, Utah
    The process of re-adjusting all the slides and leadpipe and bell to make an acceptable C trumpet may very well be more work than it's worth. Unless you are looking for a challenging project and don't mind the time, money, and possible end result that's not what you were looking for. I'd just like to say that there are so many possibilities out there with regards to used C trumpets. I have no doubts that with a little patience and luck, you'll be able to find a fine C specimen.
  8. ComeBackKid

    ComeBackKid Fortissimo User

    May 11, 2009
    Yorba Linda, CA
    I realize that this is an ongoing debate - just as is the debate over lacquer vs bare brass, Bach vs Kanstul (or whatever brand you like), cornet vs trumpet, synthetic vs petroleum (valve oil), and many other controversial issues. In this case, part of it is personal preference, to which we are all entitled, some of it is 'hobbyism' - just want to try something, and some of it relates to legitimate musical issues.

    I, for one, do not have a particular desire to tackle a conversion myself. I cannot imagine how to measure and cut the slide pipes accurately enough for it to work well or look decent when I am done. But, there are shops who do this work and there are people who claim that a converted Bb trumpet makes a perfectly acceptable C trumpet (of course, 'acceptable' will vary with the person or group who hears the result).

    So, it seems to me, that aside from the personal preference and workmanship issue, the real question comes down to tone, timbre, intonation, and other 'playablility' and ' listen-ability' factors which can, to some extent, be measured.

    I propose an experiment and I will publish the results when I am done. I have a group of friends/associates who are highly qualified musicians - some are brass players. I have a trumpet that I am willing to make the subject of this experiment. I know a shop that will do a Bb-to-C conversion (they have the tools and skill to do it right). Here are the steps that I will go through to conduct the experiment.
    (1) I will have a couple of the brass players play the trumpet and a couple of the others listen to it to create a subjective evaluation of tone and intonation issues.
    (2) I will have a friend play his 'C' trumpet (I am not sure of his model yet) for the same group with the intent of trying to create a meaningful description of the perceived difference between the sound of the Bb and the C trumpets.
    (3) I will then send the Bb trumpet to the shop to have it converted to a C trumpet.
    (4) I will then have a 'blind' evaluation using the same group of listeners where they hear both the factory-built C trumpet and the converted 'C' trumpet to again compare the tone and intonation. This is to see if (a) the converted 'C' trumpet has intonation equal to the factory C, (b) to see if the converted trumpet has changed its tone as a result of the conversion, and (c) to see if the converted trumpet is as pleasing to hear as the factory-built one.

    I will then post the results here. Is there any other comparison that anyone thinks I should make? For example, on intonation, I plan to simply let experienced musicians see if they detect a sense that the intonation is off. Would it be worthwhile to compare it using an electronic tuner or a comparison to another instrument? (I have seen postings on this forum that suggest and electronic tuner is not useful for tuning a trumpet due to the many overtones and they way the ear interprets those overtones vs the way the electronic tuner does).

    Any questions or ideas?
  9. jimc

    jimc Mezzo Piano User

    May 21, 2009
    Spokane, WA USA
    I have a converted Bb->C trumpet, a Couesnon. It was done by a repair tech student. Seems to play OK to me, but what do I know? I only wanted a cheap C so that I wouldn't have to transpose if I wanted to play along with my wife (oboe). The Chinese C's weren't around yet or I might have gone that way, but I like the idea of an older, salvaged horn better. I might suggest that you record your before and after sessions, and make a point of having the same player(s) play the same things on it, before and after. That opens up the possibility of getting additional opinions on the sound and intonation.

    I think that brand differences might make the comparison with the 'real' C less meaningful. I find my Couesnon brighter than my usual horn. OTOH, my old Conn Bb also seems brighter than my usual horn, so what does that tell me?
  10. gzent

    gzent Fortissimo User

    Nov 5, 2003
    Rochester, MN
    Too generalizing, R.

    The Olds Ambassadors (I know 5 of the owners ) that my brass tech friend converted from Bb to C using measurements from a Yamaha C all played just fine with good intonation.

    When I replaced the leadpipe on my Olds Bb/C horn with a Pilczuk the intonation became quite good.

    The idea that all converted Bb/C horns are inferior has been repeated by people who have not played them. Its just simple physics. If you make the slides the correct lengths and use a leadpipe with a taper that works with the horn then its really not some mysterious process to build a decent playing C trumpet using existing parts from a Bb trumpet.

    I converted a Yamaha Bb into a C and it played just fine.
    [Ask trptchopdoc if you don't believe me.]

    I'm not sure why people get so upset when told that yes, it can be done and has been done with decent results.


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