Hohner B2AV-WS headless 5 String Modification

Discussion in 'Luthier's Corner' started by Lavrans, Jun 2, 2012.


  1. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    Hohner B2AV-WS headless 5 String Modification

    Dear friends: I have acquired this Hohner bass with the plan to reconfigure it into a short-scale headless 5-string. The distance from the 2nd to the 14th fret is exactly 15 inches, which gives a perfect 30 “ scale. The plan, and reason I’m doing this on relatively cheap but playable headless bass, is to saw off the neck just behind the 2nd fret. Then I will trim the head at the 0 fret, and shorten the neck by 3 3/4” (90 mm). The head can easily be glued and screwed back on, and with a string adaptor, I’m in business.
    The problem is what to do about the truss rod. I’m asking for any advice anybody might have about what is involved in shortening it. I haven’t done anything yet, but I’m assuming that I can just remove it by unscrewing it, pulling it out of the neck, then figure out some way to shorten the rod and reinstall it. But I don’t want to try to remove it and wind up damaging the neck. I don’t want to get involved with removing the fingerboard if possible.
    Any thoughts on how to do this?
  2. ourworldisgrey

    ourworldisgrey

    Joined:
    Jan 7, 2009
    Location:
    South Jersey
    Other than the headless part, wouldn't it be easier to tune to DGCF and then capo the second fret?
  3. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    I did try that; if the business with the truss rod can't be solved, then that would be the next best solution. I would need to use slightly heavier strings and adjust the action, but that would work. I'm ancient, and I have trouble with a full scale bass, or I'd just play it as is.

    Thanks!
  4. MPU

    MPU

    Joined:
    Sep 21, 2004
    Location:
    Valkeala Finland
    I'm not sure what kind of a truss rod is in Hohner neck. I'd make something like Status BendWell (not as deep, maybe a bit shallower than the fretboard) if I wanted to make a 34" scale headless neck to a 30" scale neck.

    http://www.flickr.com/photos/ever1993/5600887716/

    Marko
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  6. bassteban

    bassteban

    Joined:
    Aug 12, 2004
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    Northern California
    This sounds so wrong that I must encourage you. Also- please post pics. :)
  7. Lavrans

    Lavrans Supporting Member

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    Jun 16, 2011
    Location:
    Cambridge MA
    Thanks for the suggestion and the photo. This could also work.

    Larry
  8. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
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    Cambridge MA
    Hmm. I went to the Status website, and this is a modification they build into a 32" headless bass. However, some home-made version of this idea may be useful to me.
  9. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    AFter much research and an exchange of emails with the Hohner guys, I am convinced that the only way to do this mod by physically shortening the neck at the head is to take it to a good luthier, have the finger board removed, and then modify or replace the truss rod. I have no idea exactly how the TR is structured or imbedded in the neck. Judging by a number of posts on the topic, it seems to be fragile, prone to breakage and other screw-ups.
    So for now, I'm going to go with the capo on the 2nd fret solution. With the right gauge strings and the action adjusted, this seems to work fine. I found an online source for fret marker decals. Unless I get some new and more useful info about the dag-bladdet truss rod, that will be my mod. Thanks to all who contributed to the dialog.
  10. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    Update. I have successfully gotten the neck shortened to a short scale, with the original 2nd fret now the 0 fret. The truss rod was totally frozen, so we sawed it off and hope it will just add some stability. The fret-board was not really removable. The job was by DK Parsons Guitar Repair in Watertown MA- pictures and details to follow. We're now replacing the harness using an Aguilar OBP-3TK/PP Onboard Preamp 3 way, with treble, mid and bass controls, and changing to single volume, and a blend.
    The Steinberger bridge is a problem because the distance between the tuners and the saddles is so short that the end windings end up resting on the saddles. Hmmpphh. Looking at replacement bridges.
  11. Stealth

    Stealth Supporting Member

    Joined:
    Feb 5, 2008
    Location:
    Zagreb, Croatia
    Can we see pics of it in its current state?
  12. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    AS soon as I get them. Assuming I can figure out how to post them to this list. ;=)>
  13. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    Here are some pictures. The first is of the original configuration- 2 volume pots, and a stacked tone pot.
    The second is of the neck shortening. I will post two more pix in the next message.

    Attached Files:

  14. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    Two more pix; The 3rd picture in this set shows the wiring for the Aguilar OBP-3 harness being stuffed into the well. The 4th picture shows the final set-up, with the ABM bridge and tailpiece, and the 5 pots. The jack was moved to the back end. If I had a do-over, I would expand the well, line it with copper foil, and put in a separate battery box.

    Attached Files:

  15. churchpark

    churchpark Supporting Member

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    Jun 21, 2007
  16. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    OMG, indeed. I had another luthier re-do the wiring and it plays even better than before.

    Attached Files:

  17. Lavrans

    Lavrans Supporting Member

    Joined:
    Jun 16, 2011
    Location:
    Cambridge MA
    Now that I've got the whole project finished and working, I've decided to sell it. I bought the Brice short-cscale 5-string, and the Department of Redundancy Department says it must go. $800 or BO. See the For Sale section for details. also selling an Aguilar Tone Hammer 350 $400.

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