GRAPHTECH GHOST/HEXPANDER SYSTEM
STRATOCASTER INSTALLATION
PAGE 2

 

 

THE HATCHETWORK

The most important thing you should realize before buying Graphtech's Ghost/Hexpander system for Do-It-Yourself installation is that the difficult part is the hatchetwork you have to do to your Strat. Although their system is wonderfully modular and comes with terminal block plugs that make the connections a breeze, that aspect is trivial compared to the work you have to do to fit it inside your Strat. That applies to any internally installed 13-pin system, including Roland's GK-2A pickup.

There are three main areas of Strat body hatchetwork to consider, plus an optional one:

THE SCRATCHPLATE First, the scratchplate/pickguard needs clearance for the saddle pickup wires to pass under to enter the central control cavity. This wasn't too difficult, but there are a few "gotchas" that you should be aware of. Maybe it's just my scratchplate, but cutting the grooves was more difficult than I'd expected because the plastic material was so slippery. I used a rotary flexshaft tool (Foredom/Dremel), first trying to cut a generous groove for each string with a small ball-ended bit. The bit wouldn't stay put and skittered a few times dangerously near the side of the bridge pickup (yes, to be safe, you should remove the pickup). I then switched to using an emery cut-off wheel which let me cut coarse grooves without the skipping problem-- However, you do have to make sure that you don't begin cutting into the bridge pickup! With the grooves established, it was much easier to enlarge and clean them out with a ball-ended bit. But the problem of skipping still existed to a lesser extent and I'm just glad that my Seymour Duncan pickup had a fabric wrap instead of bare lacquered wires (and that I used a low speed Foredom). This job wasn't too difficult, but was just more difficult than I expected.

One thing which still concerns me is the routing path of the saddle pickup wires. The pivoting edge of the bridge is usually higher than the face of your guitar, which creates a bit of a drop off. With "American Style" two-pivot point bridges, you can adjust the entire bridge to float quite high above the face. The gap creates an unsupported area of the pickup wires which is subject to the most flexing whenever the tremolo bridge is used. I'm mainly concerned that the flexing and wear could eventually lead to unreliable performance, or possibly a pinched pickup wire. Not that there's anything you can do about it except make sure that the wires can "breath" and aren't pinned down so that they can only flex at exactly the same point every time. This is especially important if you plan to set the intonation since you don't want to try to stretch the wires-- they're not rubber bands. I suppose Graphtech thought of this problem, which is why they use a special Teflon coated wire.

THE CHANNEL The second modification was the most difficult, which was something I didn't expect. It's a Strat thing: The channel between the control cavity and the jackplate cavity needs to be enlarged to accommodate the ribbon cable. This cable will eventually connect through the jackplate cavity to the hole you create for the 13-pin jack. The first challenge though, is getting it to the jackplate cavity.

Easier said than done. Fender's manufacturing process has it easy since they only have to create a small diameter channel to run two wires through. You'll note that the hole is drilled at an angle, from the jackplate cavity down towards the control cavity: Easy to do. However, making a much bigger channel to accommodate the ribbon cable and bar-like pin connecter is a lot harder, especially if you don't want to accidently screw up the finish on your guitar. A long, fat drill bit would probably work, but mine wasn't nearly long enough and I wasn't going to buy one just for this. The problem is that you have to get both the angle for the bit to clear the guitar body's surface, and the length to drill all the way through. The big concern is not to cut or grind at the opening of the jackplate cavity by having too shallow an angle, where it might not be concealed by the jackplate. If your drill bit is too short, your drill may get too close to the body and the chuck will grind away at the opening of the cavity. I spent quite a while at this with thinner bits, changing the side to side angle while maintaining the vertical angle to grind away material. It removed a lot of material from the openings, but left with a bottleneck pinching within the channel. Fortunately, I happened to have a right-angle attachment for my Dremel. This seemed a more effective way to remove wood than gnawing it it with a thin drill bit. However, the right angle attachment is relatively bulky and there's really not adequate room inside either cavity to just stick it in there and use it, so it needed to be approached from a side angle within the control cavity, gradually straightening it out as it removed enough material. Even that didn't make the job a breeze-- there's always the danger of a rotary tool seizing in the wood and getting away from you before you can do anything about it. So of course, it happened. I had a fairly bad accident in which the bit seized and skittered across the lacquer surface between the two cavities. It's difficult to control that sort of backlash, even in the best of conditions. Fortunately, the most violent damage was done to the cavity's edge under the scratchplate. The visible surface was marred by a couple of light teeth lines which aren't too bad looking. For this procedure, it's probably smart to protect the surface with something really tough that a steel cutter won't be able to chew through in a split second-- like maybe leather, foam tape or copper sheeting? I don't think masking tape would really offer much protection. This is probably the single most compelling reason to have the job done by a Luthier, especially if you care about nicks and scratches on your guitar.

Graphtech Hexpander Stratocaster InstallationTHE 13-PIN JACK CAVITY Surprisingly, this was probably the easiest of the three required hacks, or at least not much harder than modifying the scratchplate. Even though the quantity of hackwork is greater, the work is straightforward with easy access, and there's little danger of screwing things up if you're careful. I situated my jack in the "usual spot" for this kind of modification; right below the 1/4" jack, on the curved side edge. You make a big hole from the outside into the jackplate cavity. The hole needs to be big enough to fit the ribbon cable and connector through. The outer edge cavity needs to be deep and wide enough to fit the 13-pin jack into-- a squared shape works well enough. Shaping this cavity can be done by a rotary tool, but because of the speed, you should exercise caution so the cutting bit doesn't get away from you.

Before you begin drilling, you need to do something about the jackplate-- like remove the jack from the plate. The plate is a flat black aluminum panel, intended for mounting flat on the guitar's front or back surface; that's obviously not going to work here. Fortunately, aluminum is relatively easy to bend. If you try to bend it with your hands though, the piece will probably kink in the center where the hole is cut. Instead, you can pound in the curvature by hammering the plate over a curved surface along the full length of the plate (or from the back on something like an armourer's dishing stump). This produces a more evenly distributed curvature, and you keep doing it until you've got the shape close enough. You'd probably want to protect the surface with leather or use a rubber mallet, but you can always touch up aluminum with a gun bluing solution (made for aluminum). Once you got the plate to conform to the curvature, you can get a pretty good idea of where the hole needs to be cut, how big the cavity needs to be, and where not to cut beyond. The cavity itself can look pretty funky and crude since the panel conceals it. Once again, the rotary bit got away from me and created a nick in the finish right at the plate's edge. Damn.

There's one other trivial modification that needs to be done. If you replace the regular 1/4" output jack with the stereo/switched jack that they supply, you'll probably need to route out a portion of the jackplate cavity just so it can fit. The extra stuff on the switch needs a little more room, down at the bottom area of the cavity at the bridge end. This isn't anywhere near as tough as routing the channel since the undercut doesn't have to go very far. I didn't route mine quite enough and when I first tried to plug in, the jack's ring or tip contactor didn't have any elbow room to get out of the way of the plug.

THE BATTERY BOX This is an optional routing job which is mainly difficult by virtue of the amount of wood to be removed. I've been doing all this with a Dremel/Foredom, freehand without router bits, so having the right tools probably would make the job easier and give cleaner results.

Installing a battery lets you use your guitar without using the 13-pin plug, which provides power for both the acoustic preamp and the Hexpander circuit. Plugging into the 1/4" jack brings the battery online. If you don't have a battery installed (and without the GR-33's phantom power), the piezo acoustic pickups won't have any output and your magnetic pickups will be drastically attenuated-- they plug into the circuitboards and there's no bypass unless you install a switch to do the job (a push-pull pot would probably do the job).

Graphtech's manuals show battery placement within the control cavity, which might work depending on the height of the pots you've installed (switched and dual pots are significantly taller than single pots). The main problem is access: In order to change a battery, you have to remove the scratchplate, which means that you have to loosen or remove strings.

There's a more convenient no-routing option for battery placement in Strats, which goes way back to the old days: You turn the 1/4" jackplate inside out. The formerly "innie" jack cover becomes an "outie", leaving enough room beneath it to place a 9-volt battery. This might be a bit more challenging with a ribbon connector in there; I don't know because I opted for a separate battery box. The main drawback of this arrangement is that it's a tight fit and after years of battery replacement, the two screwholes might become a bit worn, but that would be easy to fix.

I got my battery box from Stewmac.com, thinking that if I was going to be hacking up my guitar, I might as well go for broke. There's probably an argument against removing too much wood from a guitar due to the way that affects the tone; however, I'm of the opinion that electrical stuff associated with your guitar affects the tone in a more significant way and makes the difference between your guitar having that basic amplified tone or not. Anyway, for some reason the Gotoh battery box doesn't come with a to-scale template (they preferred to leave the bottom half of the instruction sheet blank for aesthetic reasons, prolly), so you'll have to make one using their dimensions. Tracing the bottom outline of the box won't work because there are areas cut out, and the last 1/8" before the cover plate is wider. The accuracy of your template is critical since there's not much of a lip at the cover to conceal a too-large routing hole, and the box won't fit if it's too small.

Before cutting anything, you have to decide where you're going to put the box. I decided to put it behind the bridge because that's an area which usually doesn't contact your body when the guitar is strapped on, there's a lot of wood there and because it's in close proximity to the 1/4" jackplate cavity. The last point is significant because you have to create a channel for the battery wires to go through on their way to the circuitboard. You don't want to have to create a long channel since it's nearly impossible to drill sideways through the guitar: The distance should be no more than you could create with your drill angled from outside the cavity (just like Fender does with the jackplate cavity). I eyeballed all of this looking at the front of the guitar noting where the jackplate cavity was, and then the back, to position the template-- relying to a great extent on luck and the Jedi-Zen thing. The template was traced onto the wood with a marker and corrected to match the measurments.

The most critical part of the routing job is what you do with the top entry section. After you get your hole started, you route out to the edges, exactly where the template lines are. If you're going to have a horrible finish-marring mishap, this is probably when it will happen. Naturally, I had one, but once again lucked out-- it was at the end, where the cover tabs are longest. Once you get a bit deeper, the accuracy doesn't really matter, as long as the cavity is routed at least as wide and as long as the entry. There's no penalty for routing the lower area larger than the entry area. Turning a 55 mm x 25.5 mm x 33 mm block of wood into sawdust is a long and tedious job, and it's a good idea to periodically measure the depth. Although there's a considerable safety margin, it would be horrible to accidently route all the way through to the frontside. There is another thing to watch out for though- a rotary tool's bits aren't very long, so the routing depth may bring the chuck up against the wood. You can see it in the picture above, where it's exaggerated because of the lighting-- it's a matte scuffed area which fortunately doesn't cut through to the wood.

Assuming the box is located well, drilling through to the jackplate cavity should be easy enough-- the channel only has to fit two wires. From there, the wires are brought into the controls cavity, and there should be no problem fitting them through that channel. I made one modification to the circuitry because my scavenged Hexpander pot had a simple on/off switch stuck on its butt-- the battery's ground wire (black) was run through this on its way to the circuit board (actually, to the ground on another pot). This is so that I can turn off the power without having to unplug the 1/4" jack (assuming that I remember to do so).

 

 

PAGE 1|PAGE 3|PAGE 4

GUITAR INDEX