Harpsichord

Expand all | Collapse all

Challis Revisited part 2

  • 1.  Challis Revisited part 2

    Registered Piano Technician
    Posted 05-19-2016 21:33

    It has been some time since my last post on the Challis. I have been slowly progressing on the project between piano action rebuilding/reconditioning, etc. It is nearly ready to show and hopefully sold! My plan is to have an open house and invite all the local harpsichordists (and others interested) to stop by and give it a try. Who knows, if I ply them with enough wine and cheese I just might get a sale!

    Since my last post I went deeper into the action and took it all apart (rails, nuts, screws, the works) and cleaned, polished and put it all back together. It was a real learning experience on Challis’ thinking. With all the brass polished it looks nice too!

    For now, I decided not to convert the 16’ choir to an 8’ choir. I wanted to see how it would work out with the Delrin quilling. After many attempts with different kinds of leather I just did not find a good sound. I suppose that is why Challis eventually went with Corfam for his plectra material. My guess is that when new, Corfam had a better tone than leather.

    My major concern with keeping the 16’ choir is getting replacement strings if necessary. As mentioned in an earlier post, Tim Hamilton made strings for me but he did not duplicate the hitch exactly the way Challis made them. After corresponding with Tom Wolf on hitch making, I have some hope that if the hitch is made the same fashion as Challis it just might work. If not, it is back to square one and continue to search for a solution.

    I also corresponded with James Arledge on the wound string problem. I sent him the original fine wound string but in the end he said he could not produce a good string for me. He suggested that I try rescaling to a larger diameter but I am not interested in putting in that much expense and time. I would rather convert to an 8’ choir than try that course. If anyone has a suggestion on who might be able to make a fine wound string please let me know. Perhaps someone in Europe?

    One of the interesting discoveries on this instrument was the pedal stops. I believe I mentioned in a previous post about the “half hitch” for the pedal stops. (I do not know if there is a proper name for what I call half hitch.) After quilling the 8’ register, regulating and voicing I found this option for the stop quite pleasing. It allows for two volume levels for each register and a variety of levels when combining other registers. Ed Kottick mentioned to me that keeping the half hitch in regulation could be problematic. I can see that it might be a problem with Corfam or leather. Time will tell but I believe that Delrin, being a harder material, will not be problematic. We will see.

    Overall the instrument is a bit bright but I suspect most Challis instruments were on the bright side. I believe I can take it down a bit if necessary but for now I am leaving it to see what the local harpsichordists think. Certainly the brighter sound would work in some concert venues. With the half hitch a nice lower volume can be achieved.

    The touch is good and it does not feel heavy considering all those jacks. When all registers are on the touch feels a bit stiff (even with proper stagger regulation) but if I take the volume down the touch with all registers on will feel less stiff.

    All in all my subjective opinion is that this is a good playing and sounding instrument. It is different from traditional construction of course and there is more sustain than in traditional instruments. I can be accused of bias but I like it!

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------


  • 2.  RE: Challis Revisited part 2

    Posted 05-19-2016 21:51
    Hi, Don,

    Super!  

    I've not worked on many Challis instruments, but agree that their sound is "just a bit bright" .

    It occurs to me that there were some interesting articles on Challis (person and instruments) published in either the Harpsichord magazine and / or the AMIS journal some years ago.  Probably searchable on line . . . also, the kind of thing that Fred Sturm knows.

    Speaking of AMIS (and, thinking of wound micro bass strings):  AMIS is having a meeting this week at the National Music Museum in Vermillion, S.D..  You might ping Anne Acker (who will probably be there) to see if either she, or someone in that hearty band, have some suggestions.

    Kind regards.

    Horace

      Original Message




  • 3.  RE: Challis Revisited part 2

    Posted 05-20-2016 10:01
    I found a couple of web pages you might find interesting, or perhaps another dead end.


    mentions wound strings (for clavichords and harpsichords)....the 16' stop would
    be quite long, so you'd have to ask if they make them that length....

    Also check out this page from Hubbard Harpsichords:


    Maybe they can make strings for you, or maybe their strings
    would work on the Challis...or perhaps they would share
    with you who makes their wound strings, if they don't make
    their own.

    We have a Neupert here with spun strings. Supposedly
    they are available from Neupert, but so far none have
    broken. I may never know! (I hope)....

    Or maybe you checked these out already....

    Good luck !

    Richard Adkins
    Piano Technician
    Coe College Music Department





  • 4.  RE: Challis Revisited part 2

    Posted 05-20-2016 10:29
    Another Link:


    and


    I won't hurt to write to them and see who might be willing
    to make strings for your Challis.


    No doubt any maker will need dimensions or samples to spin you
    some wires.

    Richard Adkins
    Piano Technician
    Coe College
    Cedar Rapids, IA





  • 5.  RE: Challis Revisited part 2

    Posted 05-20-2016 10:43

    Tim Hamilton was listed as a wire source in my

    last post. I found his email here. You may

    not have to go to the UK or Europe.


    Tim Hamilton, Cambridge Massachusetts

    email  timpianos@outlook.com






  • 6.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-19-2016 23:25

    Not exactly on topic, but I searched Challis on MyPTG, and found the June, 1932 Tuners Journal, which has an article saying John Challis would be at the convention that year in Detroit, with a good bit of background about his life (nothing special). Same thing at the 1947 American Society of Piano Technicians Detroit convention. 

    Interesting connection between Challis and the tuning organizations, but more to the point, it seems that Paul Brown, in addition to the mammoth work of producing all those PDFs of old Journals, did an OCR process, so they are searchable. This is best done by checking the box next to "Tuner Technician Magazine Archives". Then you need to download the pdf and do a search in Adobe Reader (or whatever) if you don't want to leaf through hunting for the reference.

    On topic, I wrote to a harpsichord technician in the Netherlands, Martin Spaink, to ask him about a source for thin spun wires (Facebook friends). He has something of a specialty in Pleyels (Landowska design), so I bet he has a source. I'll let you know.

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda



  • 7.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 09:31

    Horace,

    Thanks for the information. I will try to contact Anne. In case you have not seen the Challis interview in The Harpsichord magazine from 1969:

    Harpsichord - Piano Technicians Guild Professional Communities

    Ptg remove preview
    Harpsichord - Piano Technicians Guild Professional Communities
    View the selected document's details
    View this on Ptg >

    Many thanks to Fred for posting this.

    Regards,

    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]



  • 8.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 10:15
    Malcolm Rose gives some sources (European) http://www.malcolm-rose.com/Strings/Spinning-wires/Covered-strings/covered-strings.html
    Regards,
    Fred Sturm
    University of New Mexico






  • 9.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 11:21
    Don said he had Tim Hamilton make a couple replacements, but had a problem with one breaking, both first and second attempt. (See first post in earlier thread).
     
    Don, did you ask Tim if he could duplicate the tails (hitchpin loops) precisely? What are their characteristics? Photo?   






  • 10.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 13:32

    Fred & Richard,

    I emailed Tim Hamilton on 5/9 about the possibility of trying again but have yet to receive a reply. Thanks for the leads and I will pursue them all. I did try Hubbard a while back and no luck there. Attached are photos; one shows an original string and the other shows one of the attempts by Tim. Both of Tim's strings broke at the same point. I am hoping that Tom Wolf has a good point about duplicating the original. With such fine wire I can see how having the winding so tight to the loop could cause a kink in the core wire and lead to breaking.

    Regards,

    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]



  • 11.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 19:26
    Don, 
    What I see in the photos doesn't make me think the loop is to blame. Tim's windings simply cover the loop, right? So they aren't going to cause any kink. What strikes me is that Tim's wrap is copper, while Challis' is not. Who knows what it is (a magnesium alloy? some form of brass?), but I'd guess it has a lower density than copper.

    The higher the weight of the wrap (total mass in the speaking length), the higher the tension needs to be to pull to pitch. Hence, assuming Challis' wrap is lower density, you are needing to raise the tension in Tim's strings higher than Challis needed. I doubt you can reproduce the original wrap material (prohibitively expensive), but maybe you can reproduce the mass. With steel core of .005" and wrap of .003", you are pushing the limits of thinness to the max, but what might be possible is to wrap a little less tightly, leave a tiny gap between windings. I have no idea how hard that is to do, and expect it is pretty hard, but it might be possible. Otherwise, you could stop the wrap within the speaking length, but again that seems problematic (swedging .005" wire isn't something I'd like to try).
    Fred Sturm
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda






  • 12.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-20-2016 20:02

    I remember learning this lesson the hard way, by trying to replace a console bass string, originally aluminum wrapped, with a copper wrapped string of the same dimension. If one will not exercise one's wits ahead of time, one gets to do the work over again.

    I don't suppose the Challis wrap might have been aluminum?

    ------------------------------
    Susan Kline
    Philomath, Oregon



  • 13.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-21-2016 19:23

    Fred,

    The picture of Tim's string makes it look like copper but he used brass. It is hard to tell the composition of the original wrap. I just assumed brass but as you mentioned, it could be some other alloy. Have a look at picture #9 from my earlier uploads. Note that the very top 16' strings have some other sort of wrap. Perhaps aluminum alloy? Challis was into aluminum!

    Harpsichord - Piano Technicians Guild Professional Communities

    Ptg remove preview
    Harpsichord - Piano Technicians Guild Professional Communities
    View the selected document's details
    View this on Ptg >

    You are correct, it would be expensive to analyze and reproduce the wrap. That is not in the future right now.

    I see your point about how the loop was made. another guess is that his helix of the core wire was too tight thus causing the string to break where it did both times. The helix on the originals looks fairly loose and note how the wrap ends on the original. Lots of guess work here and we may never find a definitive answer. In the end, when I made a hitch on the wrap of the second string that Tim sent it held. That may be the only way to go.

    Regards,

    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]



  • 14.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-21-2016 19:46
    I'm curious about your loop in the wrap of the broken string. Did you do a German or French loop? (German would be much easier in the circumstances, and less prone to break in general). Does the wrap extend all the way along the string, including what is put on the tuning pin?
    Fred Sturm
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein




  • 15.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-21-2016 20:10

    Well, if Challis was into aluminum anyway, I wonder what would happen if Tim made a few samples using aluminum, even though the originals were made of something different? If they held and sounded all right, would it be reasonable to do the whole 16' set that way?

    ------------------------------
    Susan Kline
    Philomath, Oregon



  • 16.  RE: Challis Revisited part 2

    Posted 05-21-2016 23:48

    Don,

    You might try (and maybe you have) sending Tim the speaking lengths and pitch frequencies together with the rest of the string parameters.  Although, I don't think he have values for the maximum recommended tensions for steel, they seem to be lower than what this particular setup is asking for.  (if you have these values, or know someone who does, they would be interesting to have)  There might be a way to change the string slightly to lower the tensions, like open winding, which was already mentioned, or something else.

    Tim tends to make the helix part of the loops not all that tightly, compared with many, so I doubt that to be the reason for the string breakage, but there is always the potential that the wires got nicked in some other way.

    Beth

    ------------------------------
    Elizabeth Harris
    Arlington MA
    518-817-9046



  • 17.  RE: Challis Revisited part 2

    Posted 05-22-2016 12:02
    The lighter colored wrap may be silver or
    even steel. You'd have to have it analyzed
    to know. They you'd have to find someone
    willing to wrap the new strings in that
    material. Sounds a bit complicated and
    maybe expensive, as you say.

    Are you only trying to replace the broken
    strings, or the whole set? Maybe you said
    before.

    Perhaps Paul Poletti would be able to do a custom
    set for you. He might be able to scale it so there's
    less chance of breakage. His wrapping process sounds
    very impressive, but maybe it is common practice.

    I don't think the bass strings are longer than
    what he's set up to do, since he also does
    Fortepianos. He doesn't say that he would
    do a Harpsichord. 

    There's no harm in asking. I'll bet it would cost
    a pretty penny, though.



    I have found the German loops for me hold very well
    and do not break.

    These mid-century instruments are interesting in all they
    tried to do to make them more versatile.

    My only visit to the Challis shop he had just finished the
    Lincoln Center harpsichord. It was the loudest harpsichord
    I think I've every heard. It had to be as the acoustics
    were so awful there. I'm not sure what happened to it.

    Good luck with the strings,

    Richard Adkins
    Piano Technician
    Coe College
    Cedar Rapids, IA






     





  • 18.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-23-2016 17:44

    Hi Fred,

    Tim made a French loop and wrapped it tight around the entire helix. As can be seen in the photo the original did not cover the helix entirely. It may be grasping at straws but I wonder if this is the difference as to why Tim's strings broke.

    Yes, the wrap extends all the way to the tuning pin end as can be seen in photo 9 of my library pics.

    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]



  • 19.  RE: Challis Revisited part 2

    Registered Piano Technician
    Posted 05-23-2016 17:46

    Beth and Susan,

    Tim got back to me yesterday and I replied today so fingers crossed!

    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]