I inadvertently posted the following on the JTV-89 board:
First of all, I am neither knowledgable about guitar construction, nor guitar set-up. I bought my US JTV- 69 in 2011 without any understanding of how to analyze the integrity of it's construction. It appeared to be very well made, and it still does. There wasn't a rough edge to be seen.
Upon first receiving it, I didn't even plug it into anything. I just wanted to see how it felt in my hands; how it played. As I played it, I noticed the E string would occasionally slip off the edge. I didn't think it was a problem with the design, but more a deficiency in my technique. I'm not a great guitarist. I silently vowed to clean up my playing style.
Then I plugged the guitar into my HD500 and was appalled at the heinous, digital-garble sound that was being produced along with the intended tone. It was only noticeable when I played near the middle of the neck. I posted my problems somewhere on this board (probably archived now). No one else seemed to be having the same problem, but suggestions regarding further set-up prompted me to take it to my local Guitar Center (it had already been set-up by Sweetwater where purchased). The guy at GC, who has years of experience, set it up, but failed to actually plug it in to an HD500 (they had a Pod XT family unit). Anyway, it sounded good in the store as I played it through the XT unit (string still occasionally slipping), but when I got home and plugged it in to the HD500, the heinous sound remained.
I related my problems to a recording engineer friend of mine. He asked me if I could detect any string buzz at all. I didn't think there was, but after listening very closely, I could hear it. He said that, while buzz is not an issue on normal electrics, some DSPs don't process string buzz very well. He said if I eliminate the buzz, the problem would probably go away. So I took it to a different (veteran) guitar specialist, lent him my HD-500, and asked him to do what he had to do to eliminate the string buzz, and to then test the guitar on the HD500 unit. When I got it back, it sounded great. The action, however, was way higher than I was comfortable with. And the string slipping was worse than ever. Completely frustrated, and depleted of funds (having spent $4000 by this time), I set the guitar aside and proceeded with my current recording project using other guitars.
Over the past two years or more, I have only occasionally picked up the guitar. Every time I play it, I get this sick feeling in my stomach. I hadn't been on the Variax boards and wasn't aware of the fact that the slipping was a common problem and that there was a 'fix'. However, a few days ago, I picked up the guitar and actually noticed the difference between the two distances: that of the top E string and the neck, as opposed to that of the bottom E string and the neck. The bottom E has almost HALF the clearance. I also noticed that the strings do not center over the pickup magnets: they ride low. I thought that maybe it was a problem with the neck being slightly off kilter, and that if it angled upwards more, the new nut position would cause the strings to reposition more and more, the closer they got to the highest fret, finally centering the strings where the neck ends. This, I believe, is the reasoning behind the nut 'fix'. The problem with this 'fix' is that, at the nut, the strings are perfectly positioned on the neck. So, the problem can't be with the nut.
Then I took some measurements of the bridge, and noticed that it is not where it should be. Following the lines of the neck, the bridge is positioned about 1/16" lower than it should be. The pick-ups are in-line, but the bridge is not. Additionally, the bridge angles slightly; it isn't parallel to the frets (not as big of an issue, as the intonation can be adjusted to correct this).
So, in my opinion, the problem with the design JTV-69 is that the holes for the bridge were drilled in the wrong place.
Any suggestions on how to proceed?