Blocking a PRS tremolo... need advice

Discussion in 'Electric Instruments' started by krugerj, Nov 1, 2018.

  1. krugerj

    krugerj New Member

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    Hey guys, I have been having some serious troubles with the trem system in my Custom 22, so I decided to just block the thing off. I blocked with a little piece of wood sanded down to fit in the cavity (as seen in the photo below).

    Now that I have the block in though, there is an angle to the bridge -- is this at all damaging to the knife edges on the screws?

    I have tried messing with the bridge fulcrum screws to lower the bridge, but that caused the action to be too low and would require another full set up to get working properly, so I raised it up a bit again.

    Any help would be appreciated!

    Thanks.


    Photos:
    Currently how it is blocked off
    [​IMG]
    [​IMG]

    Before "screwing around" with the fulcrum screws:
    Without the block (floating):
    [​IMG]

    Blocked (BEFORE):
    [​IMG]
     
  2. Russ73

    Russ73 New Member

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    OP I have 2 PRS with trems and neither of them are completely parallel with the body, theyre both intonated well and set up well and play great, on my S2 standard 22 the trem is almost touching the body like yours, if it bothers you loosen the springs til its parallel but I think youre fine...
     
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  3. AP515

    AP515 Mostly Normal

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    It won't hurt the tram to be like that, but it probably raised your action.

    To fix it just get a thicker block. The block fights the tension of the strings. The springs are there to balance the tension from the strings and make the trem sit level. If the block hold the trem at the right location the springs can be relaxed and the strings will press against the block instead of the springs. A little bit thicker block will bring the trem back into vertical alignment.
     
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  4. garrett

    garrett knows just enough to be dangerous

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    You need to take a mm or two off the thickness of the block. Nothing a few minutes with some sandpaper won't fix.

    If you adjusted the bridge height with tension on the screws, the knife edges are f-ed.
     
  5. Big Mike

    Big Mike This space for rent

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    Need to put a block on the OTHER side of the trem block under the springs,.Then tighten against it.
    Measure to make sure bridge is parallel to the top so as not to screw up the edges.
    Blocking on the side you are just means you can't pull up.

    Return tot he original action as best you can, bridge parallel.
    Cut a block to fit between the other side and the cavity wall. tighten against it slightly.

    Will actually still work for down action.
     
  6. krugerj

    krugerj New Member

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    Right, so addressing the points in the above messages:

    1.
    My action went down rather than going up as the bridge went from floating to locked down by pulling up -- the block had to be sanded down because it was too thick to begin with. The claw is screwed down as far as it can go, a thicker block does not fit in the cavity. The thickness as it is right now is the thickest I can go (the spaces you see are because the actual block is not uniformly rectangle)
    2.
    What do you mean "the knife edges are f-ed'?
    3.
    The way the tremolo bridge works is reverse. Having the block where it is now blocks pushing the bar down (i.e. flattening the strings); I can pull up as it is now to release the block.

    Having the wood block on the other side of the trem block would rather limit pulling (sharpening) movement.
     
  7. Big Mike

    Big Mike This space for rent

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    So you want to block it but still pull up?
    So you're not really 'blocking' the trem, you're putting a travel limiter in it.

    I'd just go buy a tremol-no.
     
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  8. Big Mike

    Big Mike This space for rent

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    He means on the knife edges, if you monkey'd with those while under tension, or basically adjusted them in any way out of spec, the screws and trem plate are ruined. (or can be)
    Exactly why I had to put a new bridge on mine after a tech screwed with them.
     
  9. krugerj

    krugerj New Member

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    No... I have blocked it off completely. It does not bend up in any capacity, only a millimeter to allow the block to fall out.
     
  10. Big Mike

    Big Mike This space for rent

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    Right. so you're better off blocking on the other side and tightening the trem against it, so if you push down it with your palm the bridge won't go closer to the body.

    Then leave the arm out.

    The way you have it has the bridge string angle all wrong, and is wearing the knife edges incorrectly.
    Bad.

    Pull it out,
    set bridge back to parallel to the body.
    cut small wedge and place between the body and trem block under the spring side.
     
  11. Big Mike

    Big Mike This space for rent

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    See this pick?
    You actually don't NEED the one behind the trem where you have it.

    [​IMG]
     
  12. garrett

    garrett knows just enough to be dangerous

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    Yes, exactly. If there is any tension on those screws when you turn them, you are grinding down the knife edges. Since it's an older guitar, worn knife edges could be part of your existing problems anyway.

    Since you're just going to lock it down anyway, it's not that big a deal right now. It will just cause stability issues if you ever want it to function properly as a trem again.
     
  13. merciful-evans

    merciful-evans Portsmouth uk

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    I cut the wood block to fit precisely (+/- 0.005") into the back cavity. Then I cut a 2nd block to fit into the other (springs) side. The springs are now entirely removed and the bridge is solid & stable. The bridge sits entirely square as it did originally. I replaced the spring screws so the plate sits flush to the wood.

    That is what I did with the SE Custom 24.
    Odd though it may seem, I tried to restore the trem system a few weeks ago (encouraged by the CE 24 trem. The first trem I have ever used that works without issues) and could not set it it right at all. So the blocks went back in the same day.
     
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  14. Big Mike

    Big Mike This space for rent

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    Excellent point.
     
  15. shallbe

    shallbe New Member

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    You can adjust the screws under tension, you just have to know how to do it, and do it slowly. On the knife edge, the screw turns easily. And there is a decent amount of tolerance there. Past that, it is hard to turn. You can move the whole bridge up or down against the body slowly by starting on one side of the screws and turn in the direction you want, until you feel tension on each. 1 to 6. Repeat. Before you know it, you are where you want to be.

    I have no idea how many times I have done this to my and other friends guitars. I like my PRS trems to float more than factory spec. I learned this from a great English tech on TGP that was amazing (guitar and amps---the dude could do it ALL), but someone pissed him off and he never returned. Keep in mind, I have been setting up guitars my whole adult life and I proceed with caution no matter what I'm doing with an instrument.

    Why did I have to learn it? Because I had a defective concave bridge plate from the factory and the PRS trem would not stay in tune. It turned out to be a production issue with a run of trems, where the straight line screws were not on the knife edge. PRS acknowledged the issue and offered to replace it if I sent in the guitar----but it was my only gigging PRS at the time (2003 Orange CU 22 Artist). John had a PRS guitar with the same issue (we both submitted photos) and he taught me how to make sure the screws were seated in the knife edge, under tension, regardless of the plate shape.

    When done correctly for that guitar, they were not level as typical, but the trem stayed in tune great and the knife edges were not ruined, even though they had been abused a bit.
     
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  16. bodia

    bodia Authorities said.....best leave it.....unsolved

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    Dude, Jedi!
     
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  17. krugerj

    krugerj New Member

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    Okay I tried adding a block behind the trem block as well; I replaced the one in front as well, since I do double stops, and that was the point of blocking it in the first place (second to tuning stability). The claw is completely tightened all the way to the screw heads.

    I think I might have completely f-ed the bass fulcrum screw; I didn't mess with it, but when fitting the block, the bridge got knocked out of alignment (as you can see in the photo) and I could not do anything to move the bass side. This is the current state of affairs:

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  18. Collywobbles

    Collywobbles New Member

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    I can't help thinking you're trying to resolve a tuning problem in a really strange way. If you really want it blocked for double stops then fine. If you're just trying to stop the guitar going out of tune then replacing the trem (if damaged) or setting it up properly seems a much better way to go to me. If it's not set up properly then the video here tells you how to do it. I've had to reset / reinstall a few PRS trems because they've been messed with before I bought the guitar - mostly people seem to want to screw the pivot screws right down and set it up like an old Fender. However, the trem is not designed like the old Fender trem and the the knife edges need to sit in the notches machined in the pivot screws. Based on worn trems I've seen the trems holes tend to go oval when they wear so that and damage to the notches on the screw posts is what I'be be looking for if I wanted to see if it was wear that was causing the problems. However I had a 1986 Custom with a very worn trem that still held tune great when set up properly. Lastly, I noticed was the wound strings in your pictures look fairly large - if you're using anything much above 46 guage that migh be part of the issue. Good luck.

    A worn trem block from a 1986 Custom - wear visible on the knife edges.
    [​IMG]

    Same trem block - you can see some holes have worn oval, others less so. It still worked fine when set up properly.
    [​IMG]

    Jonh Mann maufactured the trems fitted on the early guitars (up to around 1992). This is how he suggests you set up a PRS term. The first part of the video is about re-sizing the holes on an import guitar so not relevant here. My own observations are the neck angle controls the height the bridge needs setting at. I've had some older guitars with fairly shallow neck angles and setting the trem using the hex wrench size used in the video put the trem too high so I had to re-do it using a smaller wrench as a spacer. Basically you want the action to be sensible with the saddles set fairly low in their adjustment range - set them too high and it increases the mechanical advantage the strings have, which in turn will incrase string tension.

     
    #18 Collywobbles, Nov 2, 2018
    Last edited: Jul 11, 2019
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  19. Collywobbles

    Collywobbles New Member

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    John Ingram worked with Paul in the early days and set up most of the early guitars leaving the factory. These two videos show how he sets up a PRS. There are lots of setup videos on YouTube - John Mann (above) and John Ingram are the two I'd trust. John Ingram also covers setting the trem block.



     
    #19 Collywobbles, Nov 2, 2018
    Last edited: Nov 2, 2018
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  20. Collywobbles

    Collywobbles New Member

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    In case you've not seen what the trem pivot screws look like... These are fairly new design screws from John Mann - the older ones look a bit different (and the very early ones a bit different again, with a very narrow groove) but it should hopefully be obvious they have a machined groove / notch in them. The trem knife edge fits in to these. I think 'knife edge' is a bit confusing as really it's just a contersunk drilled / machined hole in the trem base plate. Looking at the screws and the pictures of the trem block knife edges above should help explain why your block is not parallel to the guitar body - either the screws are not set equally (hence causing the apparent tilt) or the trem knife edges have jumped out of the grooves. My guess would be the screws are not set level.

    [​IMG]
     
    #20 Collywobbles, Nov 2, 2018
    Last edited: Nov 2, 2018
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