Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

Initial pipe pitch instability

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Initial pipe pitch instability

    My church has a modest, 35 year old Wicks instrument which has been maintained in good condition. Over the past few months an intermittent problem has developed within the Swell 8’ Gemshorn rank. When it initially speaks the tenor G# has a tendency to sound sharp, a few cents below A and then fall back to the G# after about a second or so. Once it settles back to the G# it maintains stable pitch. This has happened transiently and very infrequently on other notes as well within the Gemshorn rank in the past, however this new problem is consistent. It doesn’t seem to occur in any other rank.

    I’ve never seen an organ pipe do this before, and I’m seeking to understand what’s happening and how to adjust it. Any thoughts?

    Ed

  • #2
    Ed,

    Welcome to the Forum!

    My first question–Has anyone been inside the chamber, or is it inaccessible?
    Second question–Have any of the pipes been moved at all? Even for demonstration purposes?
    My third question–Has the temperature and/or humidity changed wildly in the past year or so?
    My fourth question–Has anyone changed/adjusted the weight on the reservoir, or has the wind pressure changed at all?

    Depending on how the organ was initially set up and voiced, any one of the above has the possibility of causing the issue(s) you describe above. I would say something about dust/dirt building up inside the pipe, but because of the pipe's construction that's less of a possibility.

    I hope this helps you get started.

    ​​​​​​​Michael
    Way too many organs to list, but I do have 5 Allens:
    • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
    • Lowrey Heritage (DSO-1)
    • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

    Comment


    • #3
      This happened to a rank on my church's organ as well... it may have even been the 8' Gemshorn... I am not sure. Anyways, I took out the 5 or 6 naughty pipes and wiped the bottom of the pipe and found quite a bit of dust which was presumably blocking the air. I also found that the pipes weren't sitting on the chest very "comfortably" if you know what I mean. They seemed to be slightly out of place.

      I would try those 2 options... it worked for me!

      Philip
      “I play the notes as they are written (well, I try), but it is God who makes the music.” - Johann Sebastian Bach
      Organs I Play:
      - Home: VPO Compiled from Allen 2110 parts
      - Church: M.P. Moller 1951 (Relocated 2015) 3 manual, 56 stop, 38 ranks (Opus 8152)

      Comment


      • Philip Powell
        Philip Powell commented
        Editing a comment
        I will say that mine definitely wasn't near a whole half step (if that makes sense) in difference.

    • #4
      Welcome to the forum! This is a strange phenomena, but the fact that it corrects itself suggests it is the pipe’s transient. Pipe transients may change over time, either because of changes in the pipe, or changes in the wind supply, as Michael suggests. One possibility is tin pest, or some other kind of breakdown of the pipe material, another is that the pipe has fallen out of voicing or regulation. The pipe probably has to be examined and/or revoiced/regulated by a professional.

      Comment


      • Larason2
        Larason2 commented
        Editing a comment
        By the way, the fact that it is a gemshorn points to tin pest, since gemshorns and other string like ranks tend to be made with higher tin contents to help bring out the harmonics.

    • #5
      A physical inspection of the offending pipes and the chest is in order. While other issues may be present as noted above, it is possible that the pipes are simply not staying seated properly on the chest when this happens.

      When you go into the chamber, look to see if the offending pipe looks different from the others in the rank in the way it is held in place. For instance, if there was felt glued to the inside of the rack board hole to cushion and hold the pipe vertical, has it deteriorated or fallen out?

      Remove the pipe and examine the the toe of the pipe for any debris or irregularity. Do the same with the toe hole in the top board of the chest. Clean both with a soft rag. With the blower running, have someone press the appropriate key to sound the note multiple times to blow the wind directly from the chest into the air to clear any debris from the channel and expansion chamber. Then replace the pipe and sound the note multiple times, listening for any air leak at the foot of the pipe and looking for slight movement of the pipe.
      Larry is my name; Allen is an organ brand. Allen RMWTHEA.3 with RMI Electra-Piano; Allen 423-C+Gyro; Britson Opus OEM38; Saville Series IV Opus 209; Steinway AR Duo-Art, Mills Violano Virtuoso with MIDI; Hammond 9812H with roll player; Gulbransen Rialto; Roland E-200; Mason&Hamlin AR Ampico piano, Allen ADC-5300-D with MIDI.

      Comment


      • #6
        The only thing I will add to the above is to make sure you're VERY CAREFUL when handling a pipe–especially when working around the mouth area and the toe of the pipe. If you're not careful, you can end up damaging the pipe rather than fixing the problem.

        To others who have posted: How susceptible would this type pipe (with high tin content) be to tin whiskers? https://en.wikipedia.org/wiki/Whisker_(metallurgy)

        Michael
        Way too many organs to list, but I do have 5 Allens:
        • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
        • Lowrey Heritage (DSO-1)
        • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

        Comment


        • Larason2
          Larason2 commented
          Editing a comment
          The “dirt” on the surface of the pipe could very well be tin “whiskers.” However, the problem should be resolved by cleaning the pipe, if that is what is causing the effect.

      • #7
        Here's a shot in the dark. Since Wicks chests are direct electric could it have something to do with the magnets?

        Comment


        • myorgan
          myorgan commented
          Editing a comment
          I would think examining the internals would be secondary to things that can be observed and eliminated quickly–either positive or negative.

          Michael

      • #8
        To rule out a problem with the valve in the chest, swap the pipe temporarily with its neighbor, and see if the issue goes away when the pipe is in a different spot.
        Ed Kennedy
        Current Organ - Conn 645 Theater

        Comment


        • #9
          Thanks to everybody for the great suggestions. I’ll go up to the chamber and take a look to see what I can find out. Hopefully, I’ll be able to determine whether I need to call someone who might be able to revoice the pipe if necessary.

          Comment


          • myorgan
            myorgan commented
            Editing a comment
            Great idea Ed. Please keep us posted.

            Michael

        • #10
          So after I played the service this Sunday I spent some time in the pipe room checking things out. By swapping the unstable pipe with its neighbor I was able to determine that it is the pipe that has the problem and not the wind supply or seating on the chest. I tried tuning the pipe first sharp and then flat and then returning it proper pitch, but nothing seem to make a difference. This is a very stable instability! I’m forced to conclude that the pipe has to be re-voiced, which is way above my pay grade, so I’ll call in an expert. I think the observation that this is a transient is the correct one; the question is how to restore the original speaking voice.

          I was also surprised to learn about tin pest and tin whiskers from your comments. I had no idea that that could happen, but it’s possible that the entire rank is gradually deteriorating. I played a lot of Gemshorn pieces this weekend to listen for more subtle manifestations of the transients, and I found one or two other notes where it was much faster to stabilize, but listening carefully I could hear the subtle instability.

          I am retired now, and I have more time to follow up on things like this. I’d love to learn more about organ tuning. I imagine becoming an occasional apprentice with an expert tuner is the best way to do this, but is that something that would be appreciated, or are there any other educational resources that would be worth pursuing? This is clearly part art, part science, and I imagine it takes years to acquire the skills, but it might be enjoyable just learn the basics.

          Thanks, once again, for all of your ideas and observations.
          Ed

          Comment


          • #11
            I had heard of tin leprosy, and that it is the reason we use spotted metal. I hadn't thought of it in terms of California's law - do they require new pipe organs to be lead free? I never heard of metal whiskers before, that is a pretty weird phenomenon.

            edit to add - here is a third type of metal disease - bleifras - apparently the fumes from wood, especially oak and walnut, affect the lead

            https://www.cleveland.com/science/20...rcher_hel.html
            Home Organ: VPO Home-Brewed from a former Klann pipe organ console

            Comment

            Working...
            X