Why does the Lo-Pro on my 7620 operate smoother than my 752?

Discussion in 'Pickups, Electronics & General Tech' started by takotakumi, Dec 1, 2017.

  1. takotakumi

    takotakumi SS.org Regular

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    Maybe someone can guide me or explain this:
    So I have a 7620 that came stock with the FUtone noiseless springs and brass block +a tremol-no. I loved how easy it was to rock the trem up and down compared to the lopro on my 752, which felt much stiffer. Hoping to solve this, I ordered the same set of springs and installed them yesterday.

    The lopro still feels stiffer than the lopro on my 7620, particularly pulling up the bar. Anyone know why is there such a drastic difference? I also tried without the tremolno arm so the tremolno is negligible here. That would only leave the brass block in difference.

    Could the age of the bridge somehow be the reason? This 7620 is from 1999 while the 752 is from 2016.


    TLDR: why is the lopro on my 752 feel stiffer to move than the lopro on my 7620?
     
  2. tedtan

    tedtan SS.org Regular

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    Is everything else the same between the two (string brand, gauge, tuning, scale length, etc.)?

    How are the knife edges on 752's Lo Pro?

    Is the block on the 7620's Lo Pro longer than the one on the 752?

    Also, older springs are often smoother, so you might try swapping the springs around to see if it makes a difference.
     
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  3. takotakumi

    takotakumi SS.org Regular

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    7620:
    * 10-46+56 Tuned to Standard All Elixirs

    752:
    *11-49+60 Tuned to A standad, Elixirs + Daddario

    Both 25.5" Scale
    I'm unsure of the block length.
    The knife edges should be almost new.

    I heard from someone on FB right now that springs have to be worn/broken in so maybe that's it :eek:
     
  4. Drew

    Drew Forum MVP

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    Find a tension calculator and compare the total tension of both sets of strings at those tunings. If the 752 has strings at a higher tension than the 7620, then that would make it stiffer.
     
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  5. Petar Bogdanov

    Petar Bogdanov SS.org Regular

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    Knife edges are only machined, not polished, so you're probably observing the effects of the studs and knife edges burnishing each other into a smooth surface over a period of 20 years.

    I've polished knife edges after a fuckup and the trem definitely felt smoother afterwards. I wouldn't do anything if it keeps tune.
     
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  6. charlessalvacion

    charlessalvacion SS.org Regular

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    Your scale length are the same, spring gauges are different. Try using the same gauge.
     
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  7. penguin_316

    penguin_316 SS.org Regular

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    Check your screw depths there, they look drastically different. Assuming all things else are equal such as string gauge, string action, and spring type.

    I’d try loosening the screws in the guitar body if you want the trem to float easier, then do your setup all over to get the action set/tunes up.

    You said it was particularly hard to bend up? What do you mean by that? To get the pitch to raise? Well if that’s the case your fighting the string gauge. Make sure they are actually the same and if the nuts are different as well it will make a difference.

    Final note...make sure your tuners are wound with the fewest turns possible to also prevent additional friction when using the term arm (yes, it matters even if they are locking tuners).
     
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  8. takotakumi

    takotakumi SS.org Regular

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    Thanks to everyone for the info :)
    I would not want to change the gauges at all, since one guitar is strictly the "standard"
    and the other is my "A Standard" guitar, and thus the increase in gauge. Using the same
    gauge would result in a looser tension for me.

    Yeah, hard to bend up I meant pulling the bar or increasing the pitch.
     
  9. penguin_316

    penguin_316 SS.org Regular

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    This is one of those things I could fix for you in person really easily, but I’ll be damned if I can tell you how via chat haha. Basically, make small adjustments with the term screws mounted to the guitar.

    Make small adjustments and retune/set action. Rinse and repeat as many times till you get it right. Somewhat trial and error but not really as you should be dialing it in closer and closer to your goal each time.
     

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