Altering the pitch range of a tremolo arm

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soul1
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Altering the pitch range of a tremolo arm

Post by soul1 » Wed Feb 06, 2019 9:46 am

So I have a JM with a staytrem tremolo arm, and I like how its stability and how it feels. But I wish that the range of the pitch vibrato would be more like my other JM that has the stock trem arm. What I mean is that the staytrem seems to shift the pitch a bit too much without much pressure from the arm. I'm looking to get more subtle bends from the arm, and my stock one does it better. My question is can the staytrem be altered somehow? I hope this makes sense!

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Horsefeather
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Re: Altering the pitch range of a tremolo arm

Post by Horsefeather » Fri Feb 08, 2019 3:58 pm

Aren't the two arms the same dimensions? I suspect there's some other factor at work here.

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Re: Altering the pitch range of a tremolo arm

Post by timtam » Fri Feb 08, 2019 6:13 pm

soul1 wrote:
Wed Feb 06, 2019 9:46 am
What I mean is that the staytrem seems to shift the pitch a bit too much without much pressure from the arm. I'm looking to get more subtle bends from the arm, and my stock one does it better.
Sounds like you may just need an adjusted spring stiffness. If I interpret you correctly, you would like to the arm to be moved a little less for a given pitch change ? So you want a stiffer spring action / feel ?

If you don't use the lock (so trem doesn't need to be at the neutral, lockin/lockout position) you can just tighten the spring screw. Or you could find a stiffer spring, or put spacer washers between the spring and plate to bias it more towards a shorter, more compressed spring.

I haven't needed to do any of these, so maybe others who have can advise on their success.

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Re: Altering the pitch range of a tremolo arm

Post by soul1 » Sun Feb 10, 2019 5:10 pm

timtam wrote:
Fri Feb 08, 2019 6:13 pm
soul1 wrote:
Wed Feb 06, 2019 9:46 am
What I mean is that the staytrem seems to shift the pitch a bit too much without much pressure from the arm. I'm looking to get more subtle bends from the arm, and my stock one does it better.
Sounds like you may just need an adjusted spring stiffness. If I interpret you correctly, you would like to the arm to be moved a little less for a given pitch change ? So you want a stiffer spring action / feel ?

If you don't use the lock (so trem doesn't need to be at the neutral, lockin/lockout position) you can just tighten the spring screw. Or you could find a stiffer spring, or put spacer washers between the spring and plate to bias it more towards a shorter, more compressed spring.
Other way around, I want the arm moved a little more for the intended subtle pitch change. The pitch shift in the current setup is too extreme, meaning very slight downward pressure on the arm creates a large amount of pitch shifting. Are you referring to tightening the spring screw in the tremolo assembly itself?

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Re: Altering the pitch range of a tremolo arm

Post by timtam » Sun Feb 10, 2019 5:58 pm

soul1 wrote:
Sun Feb 10, 2019 5:10 pm
Other way around, I want the arm moved a little more for the intended subtle pitch change. The pitch shift in the current setup is too extreme, meaning very slight downward pressure on the arm creates a large amount of pitch shifting. Are you referring to tightening the spring screw in the tremolo assembly itself?
Oh OK. So you can try loosening the trem spring screw from the top so that the spring is less compressed / stiff, which means the arm will tilt the trem plate more easily. Again you would lose the neutral / lock in-out position, but if you don't use the lock that doesn't really matter. But if you go too far the screw can wind itself out and you'd have to take the trem off to put it back in.

Going up a string gauge may help a little, as the increased string tension would 'help' the arm against the spring.

As noted at this link, some trems may have springs that are too stiff (vintage) and some too loose (MIJ).
https://offset.guitars/the-goodies/sett ... lo-system/
So you could also try sourcing a less stiff spring. Allparts sell a spring but it's going to be hard to tell if it will solve your particular problem or not.
https://www.allparts.com/products/bp-04 ... jazzmaster

Fender sells the AVRI spring (0019307000) but if it's like vintage it may be too stiff for you.
https://shop.fender.com/en-US/parts/bri ... 07000.html

Maybe someone else has tried a new spring or solved the same problem in another way ?

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Re: Altering the pitch range of a tremolo arm

Post by Horsefeather » Sun Feb 10, 2019 6:21 pm

It sounds like you guys are talking about two different things here. The OP is talking about geometry and timtam is talking about stiffness, which isn't necessarily related.

The only thing this change in ratio of arm-movement-to-string-movement could have been caused by is a change in geometry. A stiffer spring isn't going to alter that, it's just going to require more effort.

You need to figure out where the change in geometry occurred as your first step.

Does your new arm sit in the same position as the old one, height wise? The preload on the spring could be putting it in a different spot in its travel arc. I don't know if there's enough variation in the ratio of the Jazzmaster vibrato geometry through its range of motion to actually make this a possibility but it's worth a look.

To clarify what I mean there, the vertical face of the vibrato piece that moves is pivoting around a fixed point in an arc. If that vertical face is truly perpendicular to the strings feeding into it, then all of it's movement at the start of a downbend is tangent to the arc and directly inline with the strings. It immediately starts decreasing in "efficiency" though, as the arc includes more and more "down" motion. It's all pretty tiny amounts, though, so I don't know if this is just theoretical muck.

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Re: Altering the pitch range of a tremolo arm

Post by timtam » Sun Feb 10, 2019 6:56 pm

Horsefeather wrote:
Sun Feb 10, 2019 6:21 pm
It sounds like you guys are talking about two different things here. The OP is talking about geometry and timtam is talking about stiffness, which isn't necessarily related.
soul1 wrote:
Sun Feb 10, 2019 5:10 pm
I want the arm moved a little more for the intended subtle pitch change.
Thats sounds like less stiffness (change in force/change in distance) to me .. but maybe the OP can clarify. A given pitch change requires a fixed change in string tension (force). And the OP says he wants the arm to move more .... same_change_in_force / more_distance ... => less stiffness.

We know that he has a Staytrem arm on one JM and not on another - it's not an arm swap that has happened here; so no change in geometry. But we don't know what spring he has in the JM in question. With that limited information, the only obvious way I can see that geometry could be playing into this would be if the Staytrem arm is a different length than the other, stock one (is it ?*) .. thus giving it a different mechanical advantage over the trem.

* "The arm is the same length and same curved shape as the original American vintage arm."
http://staytrem.com/Staytrem-tremolo-fo ... 10mm-black

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Re: Altering the pitch range of a tremolo arm

Post by Horsefeather » Sun Feb 10, 2019 7:13 pm

Yeah, you're probably right that it's just a tension thing and he's simply not used to the softer touch of the Staytrem assembly, which has not as much to do with the parts as with the setup.

So timtam, your previous post is the proper advice, except in reverse. OP, just preload your spring more!

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Re: Altering the pitch range of a tremolo arm

Post by timtam » Sun Feb 10, 2019 7:26 pm

Horsefeather wrote:
Sun Feb 10, 2019 7:13 pm
So timtam, your previous post is the proper advice, except in reverse. OP, just preload your spring more!
That was my first suggestion .. to stiffen it ... before the OP clarified that he wants the arm to move more to achieve a given pitch change. Hence my revised suggestion to make it less stiff. ;)

But so as not to confuse us all further, perhaps the best suggestion now is to try both ... loosening and then tightening the spring screw ?

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Re: Altering the pitch range of a tremolo arm

Post by Futuron » Sun Feb 10, 2019 10:02 pm

Are we thinking of implementing the opposite of power steering (eg turning 5 degrees requires steering wheel to turn 10 etc)? Unless you have some kind of gear down-shift devilry, moving the arm 5 degrees will give you the same amount of pitch shift regardless of the spring tension or resistance, since the bar directly moves the plate which stretches/slackens the strings.

However, if you just want the arm to be less sensitive over all, (ie need to put more force into it to get the movement and therefore changes in pinch up OR down), tightening/loosening that spring is going to move the angle of the plate. Wouldn't it increase resistance one way but decrease it the other and also result in less possible movement one way and more the other? But if the spring was replaced with a wider/thicker spring (with the same vertical size) wouldn't that give more resistance in both directions?
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Re: Altering the pitch range of a tremolo arm

Post by Horsefeather » Mon Feb 11, 2019 11:53 am

Futuron, welcome to the debacle. You've well illustrated the continuing ambiguity of the problem.

At first blush, it would seem that the issue must be a geometric one, as pitch shift absolutely is determined only by the amount of movement of the arm, regardless how much effort it takes.

Upon further consideration, though, it seems likely that the OP has just misstated the reality of the situation and is conflating resistance to motion with actual distance traveled. As timtam pointed out, there's really no reason the two systems should have different geometry so the most logical conclusion seems to be that the staytrem is just set up looser, which tends to enable deeper bends than intended.

I think what you said about differences in effort up or down is true when the spring is being preloaded versus replaced with a stiffer one.

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Re: Altering the pitch range of a tremolo arm

Post by Ceylon » Tue Feb 12, 2019 3:31 am

Well this might not be relevant what so ever but isn't the whole thing that makes the Staytrem arms desirable that they're a tighter fit in the collet and stay in place better? And if so, wouldn't a tighter fit mean a more direct transfer of energy/response when the arm is pushed in either direction, so that a Staytrem arm might feel as if the effect of of pushing on the arm is more dramatic, causing more of the push to translate into vibrato action, than on a regular JM arm/collet where it's sort of loose in there?

That was awkwardly formulated so pardon me, I'm no native English speaker and I'm entering my post-lunch brain fog.
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