
06/08/03- These are some preliminary notes and observations
about converting Roland's externally mounting GK-2A divided pickup controller
to an internal, inside-the-guitar mounting. I eventually decided not to do this
conversion and installed a Graphtech Ghost piezo/Hexpander system instead. The
job is very similar though; Both involve some major modifications to your guitar.
Before undertaking something like it, it's a good idea to know what's involved
and what your options are. That's why I explored this stuff.
WHY CONVERT AN EXTERNAL UNIT? Roland sells the pickup in kit form,
which would be the preferred route since it's easier-- the parts are supplied
with connectors and the kits (usually) contain all the switches you need. However,
it's not really any cheaper in kit form and it's more likely that the aspiring
synthesizer guitarist will acquire an external GK-2a pickup first, and
then realize that he would prefer to have it mounted internally.
I'd thought about buying the upgrade kit and trying to sell the external unit,
but for me, it would be difficult to accept the hassle of selling and the lost
money-- it wouldn't be that much, but it's the principle of the thing.
Converting and installing an external one isn't that much more work-- there's
some extra disassembly, soldering and parts scrounging, but the hardest part--
the drastic guitar hacking-- is required in both cases, and for any Do-It-Yerself
Roland-ready project. With the external GK-2A, you don't get the internal installation
schematics or diagrams, but that's not a big deal since you can take good notes
before you begin gutting.
D-I-Y VS. ROLAND-READY VS. TOP-O-DA-LINE Hacking up your guitar isn't
for everyone, and fortunately there are alternatives. Roland-Ready Stratocasters
are reputed to be decent choices. These are currently only available as "Made
In Mexico" Stratocasters. Ego-wise, that's a tough one for some folks to swallow, and it's understandable considering the way our guitars become extensions of our personalities. Even though I may be a cheapskate, I sure don't want my beloved synth axe to declare it! That's just human nature-- we value status and bond with our guitars. We often
view one as a "favorite". I'd rather have a Les Paul that said "Gibson"
instead of "Epiphone", even if I couldn't tell the sonic difference. But there
are actual quality differences, mainly in the choice of wood and some components.
Many folks buy the Roland-Ready Strats and upgrade them with higher quality
furnishings. If mucking with soldering and guitar drilling isn't your thing,
and if you don't mind unleashing a bunch of extra parts, then that's a reasonable
route to take.
It's still a tough choice. A discounted Roland-Ready Strat isn't that
expensive and you get a lot more for your money than buying an internal GK-2a
kit at full retail price. Of course, by the time the uber-Strat upgrades are
in your Roland-Ready Strat, you've spent a lot of money... maybe nearly enough
to have bought a better tracking Brian Moore or Godin in the first place? The
least efficient scenario would be to have started with an external GK-2a, bought
a Roland-Ready Strat, upgraded it, and then finally bought a Godin. That's probably
happened a few times.
Of course, you could always just mount the pickup and external wart as Roland intended...
WHY BOTHER? That's a good question. The external "wart" does its job
and doesn't permanently disfigure the guitar's wood. One could say that it's
ugly, but that's a matter of taste. The extra bulk makes the guitar's fit into
Fender's fitted hard shell case a little troubling at first glance. However,
it's not a serious problem because, under the fake fur, the interior of that
case is lined with a compressible styrofoam-ish lining.
The main practical
reason that I see for doing it is to avoid the wear on the cord which connects
the pickup to the wart's circuitry. It happens to run where your forearm rests.
While I don't know of anyone complaining about this causing problems, opening
the circuit case shows that there isn't much in the way of strain relief on
the cord. It's held in place strictly by the pressure of the two plastic halves
being screwed together. It could be a source of trouble. If you don't do the internal conversion, turning the wart over a few times before installing it on the body will make the cord coil into a cursive "S" shape, which takes up some of the slack and gets more of it out of the way of your forearm.
Another practical reason for the conversion is to wire your guitar's regular
pickups directly to the wart's electronics. A soldered connection is always
going to be more reliable than a jack/plug connection.
Mainly though, I think it has to do with the mindset of someone who likes
the gadget side of guitars: We like guitars with lots of sound-wanking capability,
and it's cooler when it's built in.
SIZING UP THE JOB A pesky detail-- we've gotta know how it's
done to decide whether we're gonna be able to do it. Can we get the parts? Transferring
circuit guts from one place to another isn't rocket science. Basically, you
just replace circuitboard mounted switches, controls and jacks with mountable
tethered ones. For the most part, it just requires decent soldering & desoldering
skills. Generally speaking, before you desolder anything, it's a reaaaaaally
good idea to make notes and diagrams of where stuff was connected. Label
wires with sticky tags if necessary. Mark the board with a fine-tipped Pigma
Micron pen if it'll help you.
This page was started after
viewing a Japanese
website which shows how it's done. Well, sort of... Did I mention that it's
a Japanese website? Unless you can read Japanese, you'll probably rely on www.babelfish.com
for the translation and maybe even figure out that "debye dead" means "divided"
as in, "divided pickup". It's a difficult read, even if you try to think poetically
and interpret in context (what could "leprosy" have to do with guitars?). But
the site is a great source for giving you clues and has great photos and tables
showing the circuit board pinouts.
Deciding on replacement switches may require a little bit of poking around
to find out what they're doing. The "S1/Up" and "S2/Down" selector switches
are momentary contact switches. The main question is whether the switches are
normally open or normally closed-- from the Japanese text, they appear to be
normally open, which would be what you'd expect for a latching-type circuit.
However, to be sure, test the switch with an ohmmeter. You can probably test
this without removing the switches (I forgot to). If they're normally open,
you don't even need to remove them from the circuit board, just jumper the switch
with an ohmmeter and press the switch to see what it does on the meter. My guess
is that the two switches can be combined into a single 3-position, normally
centered switch. I haven't done an extensive search on where one would find
such a switch cheaply.
The 3-position mode selector switch looks a little bit more tricky,
but from reading the translated text, I got the impression that the author found
the switch "simple unexpectedly". Unfortunately, it's difficult to see what's
going on with the two-sided circuit board since the switch covers the traces.
However, I poked around with an ohmmeter and craned to see where the traces
went. It appears that the 10-pole switch actually uses only 3 connections. Half
of the switch appears to be unused, 2 of the contacts (internally connected
to an adjacent contact) are snipped and don't connect to anything. For the mixed
center position, no connections are made at all. In the guitar and synthesizer
positions, the two traces switch to the center contact, which is grounded. If
so, this could be done with a very basic and common 3-position switch. Beats
me why they used such a specialty switch unless it was the only style which
accommodated the fancy switch paddle cover.
I took a picture of the topside of the circuitboard because the Japanese
website didn't show that view. Mainly, I was interested in knowing what the
DIN-13 connector looked like so I could determine how difficult it would
be to mount inside the guitar. There's a marginal benefit in buying a new DIN-13
female jack from Digi-Key since you'd probably
have to remove the jack from the circuit board anyway. The circuit board's connector
has a flat, square face with a space to drill tiny holes for mounting to a body
plate. In fact, there are at least a couple of slots along the connector's body
which could accommodate very small nuts for the screws.
To provide "straight guitar" functionality (in case the 13-conductor cable
broke), the jack for the guitar's regular pickups could be set up so that in
an unplugged state, the guitar's regular pickup signal would be routed to the
electronics. Plugged, the signal would bypass the electronics and go directly
to the regular pickups. 1/4" jacks are available which allow several different
switching options (normally open and normally closed). I think this would also
allow the use of two cables, if one wanted to keep the signal paths separate.
The potentiometer's value needs to be determined; from the Japanese
text (and from a second disassembly), it appears to be a 50K B linear taper.
Finding a suitable replacement should be pretty easy.
Other than that, it's mainly a matter of desoldering the original components
and mounting them with stranded wire to the replacement components. The Strat's
control area has plenty of room for the circuitboard. However, the most irreversible
and drastic part of the process requires that you route your guitar's body for
mounting the 13-pin jack housing. Altering the plastic scratchplate with extra
holes is no big deal-- those can be easily replaced, but a guitar's body is
a significant and more expensive part of your guitar. You could choose to mount
the jack on the scratchplate but would lose some valuable real estate-- and
it would look kinda dorky. That's one of the reasons we're considering moving
the wart inside in the first place!