The Grun Numbering System

[Grad77]

I have read about the adjusted serial numbers during the late 80s and through the 90s. I am trying out two F50R/JF55s from Guitar Center. One dates out as a 1999-2000 JF55. The other is more interesting. I thought it was a GC mistake. The guitar was listed as a JF65 but clearly from the picture it had a Rosewood Flat back, making it a JF55. The guitar arrived yesterday and upon research I found it was made in March of 87 and was clearly labeled JF65. The DateChart confirmed it. What was up with the serial numbers during the transition period? (example JF65R). I thought JF55=Rosewood and JF65=Maple. We're there spec or cosmetic differences that were reflected in the redundant serial numbers during the transition? The 87 JF65R is a nicely built and great sounding guitar. Need to have my new Luther give it a once over. Thanks Treem and Daddiest . If it passes inspection I think it's a keeper. The 1999-2000 JF55 has some problems with wood and binding shrinkage all the way across the back of the shoulders and on the hips of the guitar. Slight shrinkage and splitting of the back seam as well. Moderate crazing on the Spruce top. Bridge is starting to lift just a hair. First 3 frets are showing dents from play ware. Not sure about the neck, the bridge may have been shaved to compensate. Gonna have it checked too. But the binding shrinkage is bad enough to make it a deal breaker for me. The Abalonie Rosette is a tempting feature. The sound is an 8 out of 10. But, that might improve with a good set up. Very interested to hear any comments on Jumbos around '87 during the start up of the Gruin Period? TTFN Guilda

 

[adorshki]

What was up with the serial numbers during the transition period? (example JF65R). I thought JF55=Rosewood and JF65=Maple.

Generally speaking that's how it works. Since '87 was the very start of the "Gruhn era", I suspect you have a very early JF-55, labeled before they had decided to use 2 model numbers to differentiate the body woods. There was a similar distinction with the F50's from which the JF55/65 were derived, "F50" and "F50r". It probably should be called exactly what it is labeled as though, for "historical accuracy".
If I'm wrong, I'm sure Hans Moust will be glad to give the real explanation. :wink:

The 1999-2000 JF55 has some problems with wood and binding shrinkage all the way across the back of the shoulders and on the hips of the guitar. Slight shrinkage and splitting of the back seam as well. Moderate crazing on the Spruce top. Bridge is starting to lift just a hair.

All those details taken together suggest theh guitar experienced some kind overheating problem to me, and maybe "thermal shock" in the case of the finish. Maybe pulled out of a hot car and opened in an air-conditioned room with no time to cool down . I'd be inclined to avoid.
Since you can't know how hot the guitar got or for how long or how often, there could be some real problems with glue integrity lurking in there, besides the cosmetic stuff.
I think there's plenty enough JF55's around that you don't have to take a chance on one like that. :wink:

 

[hansmoust]

Since '87 was the very start of the "Gruhn era", I suspect you have a very early JF-55, labeled before they had decided to use 2 model numbers to differentiate the body woods. There was a similar distinction with the F50's from which the JF55/65 were derived, "F50" and "F50r". It probably should be called exactly what it is labeled as though, for "historical accuracy".

Hello adorshki and grad77,

Adorshki is pretty close! Not exactly what happened, but there are some early JF-65s with rosewood back & sides.

Sincerely,

Hans Moust
http://www.guitarsgalore.nl

 

[adorshki]

Adorshki is pretty close! Not exactly what happened, but there are some early JF-65s with rosewood back & sides.

Sincerely,

Hans Moust
http://www.guitarsgalore.nl

Thanks as always, sir!
Now that you mention it I believe you have pointed that out before!