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Tremolo Info Project

by Henrik Hjortnaes

Identify the bridge on your Jackson Charvel guitar

The following is a look inside my personal tremolo notebook, where I collect info and specs on the many floating double locking tremolos, found on most Jackson and Charvel guitars. The many versions of these tremolos have always generated a lot of confusion and questions, so I thought this would be a good topic to include on the site.

JT-6 tremolo fine tuners

The cleverly designed fine tuners on the first "Jackson" labeled tremolo, the JT-6. This tremolo was used on both Japanese imports and USA made Custom Shop guitars around the period 1987 - 1989

Vibrato or Tremolo?

Before we get started, I would like to apologize for using the word tremolo in this article, when describing a floating locking bridge on an electric guitar. I would like to call it vibrato, like we used to in the old days, but nowadays everybody knows a floating locking bridge as a tremolo. In my opinion; when using the "whammy bar" on your floating locking bridge, the effect you get is not tremolo. It's vibrato - variation in pitch. Tremolo is a regular and repetitive variation in amplitude (volume). Now, do you hear any volume changes when using your whammy bar? Thought so! ;-)

Check back for tips and advice

Floyd Rose tremolo

It is an ongoing project, but I've come a long way since the start, so there are many models included in the following. I am trying to apply helpful comments regarding swapping and changing parts too, because many of these units are old by now and needs care or replacement. Keep checking back for more tips.

The Schaller made tremolos mentioned in the following are also found on other brands of guitars (Gibson, for instance).

The JT-XXX designations used in this article is Jacksons own way of naming the different tremolos used on their guitars, and I will adhere to that naming scheme. Many of them are made by Schaller in Germany. JT = Jackson Tremolo.

Kahler

Jackson / Charvel did use Kahler tremolos too, especially on the early Japanese imports and many Custom Shop guitars. Unfortunately, I don't know much about Kahlers, nor have I had the time to investigate them, but hopefully they will be added later. Maybe with the aid of a Kahler expert out there?

  

Schaller / OFR intonation problems

Intonation problems could arise, if you are swapping between Schaller and OFR trems on a Jackson or Charvel guitar. It varies, depending on your particular tuning and the guitar in question. Personally, I have never had any problems, but JCF member Zerberus has several times brought the following to my attention:

Jackson and Charvel guitars, factory fitted with Schallers, have the posts positioned 1/16" closer to the nut compared to OFR fitted guitars. This is to accommodate for a small difference in the design between the two tremolo bridges.

So, after replacing a Schaller with an OFR, you typically move the saddles slightly back on the OFR (away from the nut), to properly intonate the guitar again. Normally, there's enough range to do this, but things often change when you use drop tunings.

Depending on the amount of down tuning, you will have to move some of the saddles even further back and you may run out of range. The saddle simply hits the sloping piece of the baseplate and stops. No more room. This is a trial and error thing. I can't give you any guarantees that a trem swap will work 100%.

Floyd Rose saddle range

Out of range. The saddle can't go further back. It has hit the sloped piece on the baseplate. If the string is still sharp by now, you are out of luck.

  • schaller ofr tremolo intonation

Low E saddle very close to max range here. Luckily, the back-edge of the saddles are shaped accordingly, to gain a little extra space. See saddle close up

  
JT-6

JT-6 Jackson Tremolo

Used primarily on the Japanese Charvel Imports and some of the San Dimas and early Ontario period USA Custom Shop Jacksons (around the period 1987-1989).

JT-6

Replacing with a Floyd Rose Original (or similar)

Most guitars with a JT-6 can be retrofitted with a Floyd Rose Original or similar bridge without major problems. This swap of tremolos sometimes needs some minor wood chiseling done inside the trem cavity, typically in the area around the arm base to have it fully clear the cavity when being used. Apart from that, it’s a direct swap.

JT-6

Tremolo block size

Pay attention to the tremolo block size/length when refitting. They typically come in three sizes; 32, 37 and 42 mm. Most if not all Jackson and Charvel guitars, originally fitted with the JT-6, needs a 42 mm block. Most guitars with recessed trem-routes use 32 mm blocks.

JT-6

Studs, inserts and nut

The Floyd will work fine with the existing JT-6 locking nut and studs and stud inserts. If you must change the studs, be prepared to dowel the holes after removing the studs, and drill new holes for the new inserts. Why? The JT-6 stud inserts are larger in diameter compared to newer Floyd types. This is why it is not worth the hassle, in my opinion. I wouldn't change the locking nut either, unless it's ruined.

JT-6

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JT-6

JT-6, re-using the studs

Here's a Jackson Custom Shop Soloist guitar from 1987 which was born with a JT-6 tremolo. It has now been fitted with a black Floyd Rose Original bridge, but still has the JT-6 studs & inserts.

It works fine, but due to the narrow angle of which the JT-6 stud knife-grooves are cut, you can only dive the Floyd 99% before the baseplate hits the top of the JT-6 studs. In real life this is no serious problem. You can still do dive bombs and make the strings flap all over the place.

1987 Jackson Custom Shop Soloist. JT-6 bridge out, black OFR in. It still has the JT-6 studs, inserts and locking nut.

JT-6 studs re-used

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JT-6

Problems

One of the weak points of the JT-6 are its locking bolts. They are prone to stripping the head, when you use the Allen key to tighten or loosen them. It happens when we tighten the bolt too much or use the wrong size Allen key, over and over again.

New locking bolts for the JT-6 can be hard to find, but try these links: McMaster-Carr, USA (part number: 91390A440) and Nordic Fasteners, Denmark.

The English term for these is "set screw", while the Danish term is "pinol skrue". I think they are metric. Click the thumbnails on the right, to see the set screw alongside the original JT-6 locking bolt.

JT-6

Click picture to see the original JT-6 Manual

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JT-6 new locking bolts

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CH-120

CH-120

Single locking tremolo used on some of the Charvette Series guitars 1989-1991.

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JT-500

JT-500

Very much like the JT-590 (see further down) in visual appearance and measures.

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JT-500

JT-500, parts mutt with thin locking bolts

This is probably a JT-500 where someone swapped the original fat locking bolts for the thinner type, found on the Floyd Rose Original type of tremolo.

Look at the gaps in the base plate, where the now thin locking bolts are going through; the bolts are too thin and are now able to slide considerably from side to side. This may work, but it looks bad. Further down on this page there’s more info on this issue. I included this for reference only, I don’t recommend it.

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JT-500

JT-500-like tremolo, unlabeled

No further info.

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JT-570

JT-570 single locking (Schaller)

Floyd Rose licensed single locking tremolo. Used on some of the Japanese made Charvels from around 1990-1992.

It’s called single locking because it doesn’t lock the strings at the bridge; you pull the strings through the bridge and lock them at the lock nut.

It is Made in Germany by Schaller and is the Schaller version of a very early original single locking Floyd Rose bridge, which is shown to the right, in chrome, for comparison.

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JT-570

JT-570, modified to double locking

JCF member RobRR has taken a JT-570 Single Locking Schaller trem and turned it into a double locking type, by mounting saddles and locking bolts from a parted out JT-500 (which is double locking).

I am awaiting the final verdict from Rob (regarding intonation), but everything seems fine so far. Cool mod if you have the parts laying around. As Rob states, this is now practically a JT-590.

by JCF member RobRR
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JT-580

JT-580 (possibly Schaller)

Floyd Rose licensed double locking tremolo with machined steel baseplate and threaded arm.

It is rumoured that the newer (2006 onward) have parts made of better quality metal. The one pictured is from 2006.

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JT-580

Replacing with a Floyd Rose Original (or similar)

The picture here shows a swap, where JCF member HoWheels have had success in putting in a Floyd Rose Original tremolo in a JT-580 route. It looks very tight, but he says it's working. Other users have done this swap with success.

JT-580

Drop tunings

Personally, I can't guarantee it will fit your particular guitar with your particular tuning. Drop tunings typically needs the low E saddle to be moved back, reducing the available space in the route even more. See picture. Read more on intonation here.

Studs and stud inserts are typically a direct swap here too if you need that. Sometimes the new stud inserts are a wee bit too large to fit the holes in the guitar. Don't use excessive force like using a hammer to pound them in! You are running a high risk of cracking the wood around the posts. Drill to the correct size holes instead and press them in, in a controlled manner.

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JT-580 swapped with an OFR

JT-580

JT-580 Takeuchi

To the best of my knowledge, all Takeuchi produced bridges used on Jackson and Charvel guitars are made in Japan. Japan has a highly skilled metal industry and the Takeuchi units benefit from that. The metal is hardened correctly and the precision is comparable to Schaller units. Many, if not all Charvette 270's came with this trem.

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JT-580LP

JT-580LP Low Profile (possibly Schaller)

Same specifications as the JT-580 tremolo, but with low profile fine tuners.

It has small locking bolts directly on the saddles; no long locking bolts sticking out the back. Much like the Floyd Rose Pro (see further down).

Notice the two variations here; the black one in the picture has square rear corners on the backplate. The chrome has angled corners.

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Two variants of the JT-580LP

JT-580LP

Replacing with a Floyd Rose Original (or similar)

Several users have done this swap with success. The JT-580LP route seems a little larger than the JT-580 route, so there's more room for the long locking bolts of the OFR. Here's a picture posted by JCF member rjohnstone, showing a swap he did on a Jackson PC3 (in standard 440Hz tuning). Plenty of room there. Read more on intonation here.

Studs and stud inserts are typically a direct swap here too if you need that. Sometimes the new stud inserts are a wee bit too large to fit the holes in the guitar. Don't use excessive force like using a hammer to pound them in! You are running a high risk of cracking the wood around the posts. Drill to the correct size holes instead and press them in, in a controlled manner.

Floyd Rose in Jackson PC3
JT-590

JT-590 (Schaller Floyd Rose)

Floyd Rose licensed double locking tremolo precision crafted in Germany. All parts are interchangeable with Original Floyd Rose bridges (except for the locking bolts).

Even though the JT-590 is close to the real deal (Floyd Rose Original) and made at the same factory in Germany, there are some differences which pretty much also applies to all of the Jackson tremolos mentioned above.

In my book, the level of craftmanship and quality of material used on the Floyd Rose Original is superior. Many will say that the fact that the JT-590 trem is made by Schaller in Germany, at the same factory as the Floyd, the JT-590 must be as good as the Original Floyd Rose. I do not agree. I do like the JT-590 - but the OFR is just better overall. Why?

The baseplate of the JT-590 pictured is made of zinc, which is soft and easier/cheaper to produce, the knife edges are inserts of supposedly hardened steel and it has no steel threaded inserts for the saddle bolts (later models came with threaded inserts). Because of that, it's easier to strip the threads of the intonation holes in the baseplate - having threads in zinc is simply just a bad idea. Furthermore, the knife edges do not last as long as the the original Floyd. Far from. I know this for a fact, as I have used both types for well over 20 years. The original Floyd baseplate is made of high quality hardened steel, with the knife edges being part of the baseplate itself. It can really take some abuse and the knife edges just last longer. Furthermore, I think the original Floyd sounds better too. No kidding. Especially when using the old studs that screw directly into the wooden body.

Clicking on the thumbnails shown on the right, you will see pictures of both a "Charvel" JT-590 and a "Gibson" Schaller tremolo, which both are exactly the same. More guitar companies uses the same supplier, only the logo is different.

A technical diagram of the JT-590 and the Floyd Rose Original can be viewed here too.

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JT-590

Replacing with a Floyd Rose Original (or similar)

Say you have a guitar with a recessed JT-590 and you wish to put in a Floyd Rose Original? Take a close look at the size of your recess in the body before buying that Floyd. The original route for a JT-590 is not large enough to accomodate an OFR with its long locking bolts sticking out at the back. It will work, but you will have a very limited pull-up range as a result.

Picture: Notice the locking bolts of the Floyd Rose exceeding the route; they will hit the surface of the guitar if the bridge is pulled upwards - even a small pull.

Be sure to read about intonation issues here too.

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Recessed JT-590 route with an OFR.
Not recommended!

JT-590

JT-590 baseplate, Schaller "Floyd Rose II"

Yep, when you have worn down the baseplate knife edges or much more likely, stripped an intonation thread or two in the baseplate, you can replace the baseplate of the JT-590 bridge with a Schaller made "Floyd Rose II".

It is using the same bad zinc material as the JT-590, but it has hardened steel inserts for the saddle bolts. No more stripping! I did this swap and it's cool. Click on the thumbnails for a closer look at the baseplate front and back. Notice the silver-colored hardened steel inserts, which will make those threads last longer.

Later models of the JT-590 might have these inserts already from the factory, but the last thumbnail shows one that doesn't. I pulled it from a 1993 Jackson Rhoads Pro. I even pulled the fine tuners (don't ask why).

This base plate could perhaps replace baseplates on other tremolos too, like the JT-500, but I haven't tried this myself. By swapping stuff around, you might end up with a bridge that won't intonate correctly. Now you know.

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Parts

Schaller locking bolts, two types

The JT-500 + JT-590 uses the fat short one in the picture and the JT-580 + Floyd Rose Original uses the long thin one. Interchanging them is not a good idea or plain impossible, due to different sized gaps in the base plates respectively; the bolts are supposed to go through these gaps.

If you take a closer look at the two base plates, you'll notice the wide gaps on the JT-500 / JT-590 compared to the narrow gaps on the JT-580 / Floyd. The fat bolt won't fit the Floyd and the thin bolt will wobble around in the wide gapped JT-500 / JT-590 and the fine tuner arrangement will probably not work as expected. Not recommended.

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FR III

Floyd Rose III

This one you will not find factory installed on any Jackson or Charvel. It was mainly used on lower end Kramers many years ago.

I included it for reference only, in case you need the information. It's an old Floyd Rose III single locking tremolo, much like the original Floyd Rose single locking and the JT-570 seen above. Notice that it has the OFR style baseplate, where the knife edges are an integral part of the baseplate. Also, it has round "tubes" sticking out the back, compared to the above FR single locking, which has square shaped "tubes".

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Original Floyd Rose

Original Floyd Rose (OFR)

The one! Earlier ones say "Floyd Rose" on the base plate, later ones say "Floyd Rose Original". They are the same. Made in Germany stamp visible on the bottom of the base plate.

The last picture shows a licensed version made by Ping.

The string spacing on the OFR is .420 inches.

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Made under license
by Ping, Korea

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Parts

Schaller collar, fitted on the Original Floyd Rose

The Schaller collar or arm barrel can be fitted to the original Floyd bridge as well as some of the other Jackson trems if you like.

At first, the Schaller collar seems too big to fit the hole, but all you have to do is assemble the thing on the baseplate and screw it in with an Allen key. The collar will slide in perfectly (well, in most cases).

First picture shows an original Floyd with the Schaller collar fitted. Yes, the newly fitted collar is black.

Second picture shows a close-up of the Schaller collar.

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Floyd Rose Pro

Floyd Rose Pro (Low Profile)

This a low profile version of the Original Floyd Rose and has a narrower string spacing of .400 inches compared to .420 inches on the OFR.

I got a message from Jay, a friendly visitor, saying that he acquired a 1993 Jackson USA Soloist with a Floyd Rose Pro installed. The guitar originally came with a JT-590.

Jay writes: -The guy I got it from put a FR Pro in. It works completely fine but as you can see in the pics, it sits offset in the routing towards the bottom of the guitar, closer to the knobs.

-The strings run perfectly parallel down the fretboard and playability is great. Just looks a bit weird. Thought it may be helpful info for anyone looking to use one of these for a swap and your site is basically the standard for Jackson info.. Here's a few pics.

Thank you, Jay.

Floyd Rose Pro swap

1993 USA Jackson Soloist, Lightning Sky graphics, original JT-590 bridge swapped for a Floyd Rose Pro.

Floyd Rose Pro

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Notice the 45 degree cut edge
The original JT-6 locking bolt and the new one, side-by-side.
JT-6 with new, non-original locking bolts mounted. If you look closely inside the fine tuner, you can see the new bolts, which has no head. See other pictures for close-ups.
Chrome Floyd on JT-6 studs
Notice the tight space between the stud head and the surface of the Floyd. Dive range is limited by a hair but it's no real problem.
Charvette Model 150 from 1989, made in Japan, factory fitted with a CH-120 single locking tremolo.
A chrome version of the CH-120 single locking tremolo.
JT-580LP out. OFR in. Picture by rjohnstone
My Soloist 3D Grid, originally with a JT-6. Now, it has a black Floyd, but the studs and inserts are the original JT-6 ones. Works like a charm.
Ping made OFR
Blue guitar: the original JT-590 has been swapped with a chrome OFR. Notice the bad fit. Inserted pic: this is how a JT-590 looks like in the correct route (from a Charvel).
JT-580 taken out, OFR put in. Picture by HoWheels
JT-590 taken out, Floyd Rose Pro put in. Picture by Jay

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