LES PAUL PERSONAL
(PROFESSIONAL AND RECORDING)
Hey Jeff, look at what I did to your guitar!
I knew I wouldn't be able to leave this guitar alone. As a concession to the "vintageness"
of this guitar, I decided to make only reversible (heh!) modifications, primarily
to the circuitry. At the outset, I considered some of the original circuitry to
be disposable (the Tone switch and Microphone circuit), some to be desirable,
but not essential (the Decade and phase switch), and some that I'd give up very
reluctantly (the bass and treble controls).
Controls Cover Plate: The first and most straight-forward task was
to fabricate a replacement controls cover plate for the backside. Some of the
modifications I was thinking of involved hacking into that plate and I didn't
want to do that to the original plate. The plate is a very simple shape, in
a single ply .1" thick black ABS plastic. It's not too difficult to make if
you can find a similar piece of plastic to hack up. I didn't, and ended up using
a piece of .1" thick Plexiglass. The clear thing is kinda neat, but served
a more utilitarian function while I planned the modifications: It let me see
how stuff was to be positioned inside (although I still mounted the switch at
an odd angle). A good thing about Plexiglass is that you can paint it from the
inside and it looks glossy from the outside, but without any danger of the paint
being scraped off. I shielded it with aluminum tape, which also happens to keep
the paint from be scraped off from the inside.
Transformer: I wanted to install an internal impedance matching transformer
since it would eliminate the need to use the special impedance matching cable.
Originally, I thought I'd probably never use the low impedance feature so it
really didn't need to be switchable, as it is with the Les Paul Recording model.
However, it's an easy modification to add via a flush-mounted slide switch on
the back controls cover plate (being a set-and-forget control). The 10:1 transformer
was harvested from an XLR impedance matching gizmo which looks amazingly like
the Gibson one. They're not very expensive, but it's a shame to discard the
housing (which probably accounts for most of the cost) for the tiny transformer
inside. I constructed a more compact shield enclosure out of copper foil and
soldered it to the switch.
Potentiometers: The potentiometers were the biggest problem, mainly
because they involve both operational and aesthetic considerations. The pots
must have a knurled split shaft to fit the original knobs, and there are at
least two variations on shaft knurling (one fits, the other doesn't). It gets
worse: Les Pauls sometimes require the less common long shafted pots because
the pots are mounted through the wood layer, which is much thicker than the
plastic of a pickguard. To get an idea of what my option were, I removed the
microphone pot. I was pleasantly surprised to find that it was mounted with
a brass nut with an extended threaded sleeve which went into the body. This
compensates for the more common short shaft pot, and expands the variety of
values from which you can choose. This can be important if you want to install
circuitry which uses pots with values other than the usual 25K, 250K or 500K.
Another surprise was that the pot had been shimmed against the wood with a couple
of "Rhythm/Treble" pickup selector rings. Hey, souvenirs! It's unfortunate that
they didn't use the more unusual "Front/Rear" rings, but I guess they were probably
in shorter supply.
Unfortunately, the main controls cavity is fitted with a metal plate which
increases the distance to the body face and requires long shafted pots. With
the Les Paul Personal, you can't just remove the metal plate because the Phase
and Tone Select switches are riveted to a specially formed section, so that
they'll mount at just the right height. The plate provides some shielding, so
it's a good thing, but it does make the selection of replacement pots more difficult.
The original pots, with values like 1K and 2.5K, were pretty much unusable for
what I had in mind.
The Plan: I only had a vague notion of what I really wanted. Minimally,
I wanted the guitar to put out a kickass signal that couldn't be called "wimpy",
and that could overdrive stuff. Conceptually, this would transform her into
a Julie Strain-like Amazon guitar, capable of stomping any chest-thumping guitar
equipped with mere Super High Output Humbuckers. (After all, she has the largest
pair of pickups I've ever seen in a guitar.) I played around with my Seymour
Duncan Pickup Booster again and once again decided that I wanted more than just
a walloping volume boost. It's true that a really hot signal can overdrive an
input, but how an input responds can vary greatly: Feed a super hot signal into
some boxes and you get a raspy clipped sound. Feed it to a Twin Reverb and you
get an insanely loud and clean sound. As with my Stratocaster, I decided that
I wanted built-in overdrive for better control over this aspect. I considered
getting Voodoo Lab's Sparkle Drive, but since I couldn't find one locally and
really didn't know how I was going to accommodate the controls, I decided to
use something that I was familiar with: A Boss SD-1 Super Overdrive.
SD-1 Overdrive Circuit:
This time I took a picture to show where you jumper the circuit to force it
to stay on. Of course, this is necessary if you want to make it mechanically
switchable ("True Bypass"). This guitar has more than enough room so I didn't
have to cut the circuitboard in half and fold it, like I did with my Strat.
The battery box was installed in the back cover plate, and the Volume and Tone
pots were removed and replaced with appropriate value resistors. I kinda wanted
to keep the tone pot, but I didn't have any spare pot positions at the time
and figured that I could make use of the guitar's other tone-shaping circuitry
in a more global way. The Drive control leads were wired to a 1M pot located
where the Microphone control had been. The input and output were wired to Position
3 of the gutted Tone Selector switch (basically, a 3-position Strat pickup selector
switch. I was tempted to replace it with a 4-pole 5-position "Superswitch",
but I would have had to drill out the original switch's mounting rivets and
route a little wood).
I did a portion of Robert
Keeley's infamous mods to the SD-1 circuit: C2, C3 & C8 were replaced with
.1µF polyester film caps to improve the bass response. Bass is still a
little light, but there's more than there was before. I also added the 47pF
cap across the diodes (to smooth out the distortion) and increased the gain
by replacing R6 with a 2.4K resistor.
Pickup Booster: That left two more positions on the switch. Since the
controls cavity had a little more room, I put the Seymour Duncan Pickup Booster
in there and attached it at Position 2. This worked well since switching between
the two active circuits is quiet. I even managed to squeeze in the Pickup Booster's
volume control so that the switching between it and the OD could be balanced.
The circuit's original 25K antilog taper (oddball), short solid-shaft pot was
mounted where the microphone XLR jack had been, and I made a jackplate to avoid
altering the original one. It's a weird place for a control, but is actually
pretty convenient. Besides, a set-screw knob could be used there without severely
mucking up the guitar's original aesthetics.
Tone Controls: This is strange stuff, which has taken a lot of follow-up
trial & error experimentation, accompanied by much head-scratching. Earlier
in this series of articles, I mentioned that the Decade control provides a very
subtle tone-shaping effect in high-impedance mode (that I had a hard time hearing).
However, in low-impedance mode, the Decade Control has a very noticible and
cool-sounding effect, shifting the resonant frequency center in steps to a point
where it sounds very "Stratty". The Decade circuit appears to be an
integral part of the low-impedance circuitry, and probably relies on the inductance
of the pickups as part of its filter network.
So it all depends on where the Decade Control is located in the circuit; it's
very sensitive to the interaction it has with other components. If it's placed
before the input of the OD and PB circuits while in low-impedance mode, it functions
as it was designed to. However, in high-impedance mode at that location (right
after the transformer), it functions as a treble-cut circuit, but the
capacitor values are too high-- even the smallest capacitor value causes a severe
treble cut. If the Decade control is located at the output of the OD
and PB circuits, it acts as a treble-cut circuit in both low and high-impedance
modes, but with a much more usable treble cut range. Oh yeah... if you place
the Decade circuit before the transformer in high-impedance mode, you
don't get the severe treble cut, but you don't get a very noticible effect from
the circuit. To remind you, that's how the stock circuit works and my reason
for bothering to mess with this stuff...
An true electronics gearhead could probably figure this stuff out easily and
come up with the optimal component values. I'm not, so I used what was already
there and experimented...(In fact, I don't identify some of my "fixit"
capacitors because I don't know their values-- they came from a bag of yanked
parts and the identification markings are worn or too difficult to read now.)
The Decade Switch's capacitor values were selected by really smart guys for
low-impedance use. One way to make it usable in both high and low impedance
modes (if you don't mind the behavioral change in high-impedance mode) is through
switching. A 3-pole double-throw transformer slide switch places the Decade
circuit before or after the active circuits, depending on whether low or high
impedance modes is selected. (I had to put a bypass capacitor at the input of
the PB circuit in high-impedance mode to stop an oscillation problem.)
I figured that I would need to replace the Treble-cut pot anyway since I didn't
think that the original 1K pot would really work in this circuit. Instead of
a capacitor, I tried an inductor I'd saved from an old dead Schaller wah-wah
pedal. Wow: A bass-cut circuit. In high-impedance mode, together with the Decade
switch, this formed a band pass filter, where the Q would sharpen as the bass
was cut. This gave a slight wah-wah-like tonal coloration. Playing around with
this using distortion, I could "sculpt" feedback; playing through an external
wah-wah, I could tailor the signal so it was just right for the full sweep range
of the wah-- not too shrill, and not too bassy. (It also does unusual things
through a Octaver.) This eliminated the need for the original circuit's bass
control and left an extra control pot-- This became a separate presettable treble
cut control for the OD circuit (which I think sounds better when it's less fizzy);
its capacitance adds to whatever is selected on the Decade control.
The Third Tone/Mode Position: Although I'd originally configured this
position of the Tone Select Switch for passive/dead battery mode, it occurred
to me that there really wasn't a need for the passive modes. A battery change
is quick and easy, and the passive modes don't really bring much new to the
sound except reduced volume. In fact, that can be a major liability if the tone/mode
selector switch is thrown quickly and carelessly while playing.
I toyed with several options, including installing a switchable "cascade"
(PB connected to OD)/passive mode in the third position, but this really wasn't
do-able with an additional 3PDT switch (you need 4 poles). The simplest option
would have been to wire the selector redundantly: 0D-PB-0D. Instead, I did a
variation on this: At the output of the first OD position, I installed an inline
capacitor. Very simple, but with a big effect.
Installed like this, instead of shunting high frequencies to ground (like
a treble-cut circuit), the high frequencies are passed and the low frequencies
are blocked. This makes the sound different from the other OD position and can
produce a super-fizzy OD sound. Yeeeech, right? Well, yeah... very '60s-ish.
However, the interaction with the fully in-circuit bass-cut inductor and the
Decade Switch capacitors creates a much sharper resonance. Twirling the bass-cut
knob produces a very distinct "wah", and the Decade Switch selects different
frequency spectrum centers. Practically speaking, wah-wah circuits really are
easier to operate on the floor inside a pedal, but it's interesting to have
the tonality of a half-cocked wah available at the guitar at the flip of a switch.
(And to think that I made fun of Gibson's bizarre circuitry...)
Battery Control: The replacement pots for the new bass and treble cut
circuits were a little tricky. I wanted to install a battery-off switch since
it's easier than unplugging the guitar, and having this function in a pot would
make life much simpler for me. For some reason, pots with rotary switches seem
to have fallen out of favor, while the push-pull switch pots seem to be all
the rage. The problem is, push-pull pots are tall and take up a lot of vertical
space. That was relevant since I was fitting two circuit boards in the cavity,
one on top of another. Besides, for this application, having the switch function
at the end of a pot's travel seems like a good idea since you're less likely
to accidently switch power off while playing (which is not a happy thing).
They also look less dorky (which is extremely important). In addition,
the pots needed to have knurled shafts which were long enough to poke up through
the guitar's face. I wasn't going to be too picky about the value or taper,
since I had only a vague idea which values I could get by with. Fortunately,
my tool shed came to the rescue, with its supply of scavenged parts. I found
two 10K pots with SPDT switches, very small with long knurled shafts. Although
most of the effect occurs at the end of the pots' travel (audio taper), this
works okay since this makes the pots less likely to be switched off. (Anyway,
I wasn't in a position to be real picky.) The battery's ground lead goes to
the OD's treble-cut pot switch and then to the stereo/switch jack (for redundancy).
This kills power to active circuits. The other switch on the bass-cut pot takes
the bass-cut inductor out of circuit-- this is mainly noticible when using the
3rd Tone Select (high resonance OD) position and restores most of the bass.
After sewing the patient up, it was time for an extended test drive that would
determine whether I'd be forever tortured by Tinkerer's Remorse...
Nawwww... I think it sounds great, gives lots of flexibility, and despite all
the knobs, is actually easy to use. The Tone Selector switch is more accurately
a mode switch with presettable active modes to switch between (similar to switching
pickups). The active modes each give a range from clean to dirty through their
pots' settings, so it's possible to "park" and operate within a single mode,
blending in and out of overdrive and using the global tone modifier controls,
Pickup Selector, and Phase Switch for tonal variety.
The Pickup Booster gives a sparkly clean and hi-fi sound, with full-range bass
and treble-- it's indistinguishable from the unmodified passive sound, except
louder (it starts at +6dB gain). Operationally, the master volume shouldn't
be glued at 11 since the Decade and Bass Cut circuits reduce the output level,
which may need to be made up. Running the volume full-up isn't a great idea
anyway, since the Pickup Booster's high output will overdrive most inputs (It
was envisioned as a "clean" mode). Running the 25K master volume half-cracked
doesn't seem to affect the frequency response at all.
The Overdrive circuit has a different tonality, even when clean (less hi-fi)--
that variety is a good thing for the purpose of mode-switching (otherwise, what
would be the point?). However, I usually prefer the maxed OD sound with less
treble fizz. Presetting the OD treble-cut pot, PB Subvolume, and OD Gain controls
makes mode switching pretty painless. The high-resonance OD mode can provide
a radically different sound but can also be set to sound just slightly different
from the normal OD mode. Its output is usually lower because more bass is shaved
off, but adjusted for resonance, it can produce some really peaky (and annoying)
Although I originally considered the low-impedance mode to be secondary, it
does have some unique and interesting sounds which are now more usable due to
the active circuitry. The output boost from these circuits can adequately drive
a high-impedance amp, although it doesn't have the steroidal kick of its effect
in high-impedance mode. Even with the Drive cranked up, the OD output doesn't
ever get really dirty. (I suppose if I replaced the Tone Selector with
a 4-pole 5-position switch and added a PB-OD cascade mode, that would take care
The guitar's got tone...that
was never the issue. I made these modifications mainly to fix the low output of
the stock Les Paul Personal, knowing that I wasn't likely to use it in low-impedance
mode for direct input into a mixer. Yep, the guitar can rock... the active circuitry
certainly takes care of that. This has made the guitar more versatile, tailored
to my tastes and far more convenient for me: A special cord isn't required, and
the guitar can be plugged straight into most commonly-found stomp box and amp
inputs and produce a range of hi-fi clean-to-ballsy midrangy sounds at any volume
level-- with very little fuss. While this kind of stuff can be done at an amp
or stompbox, it's convenient to have this kind of fine control at your fingertips.
Also, because I'm lazy, I can leave it plugged in and just turn it off with a
switch, and the inevitable battery change takes less time than it takes for a
tube amp to warm up. The tone controls now have a very noticible effect on the
sound and produce a range of tonal variety that isn't found on most guitars. (In
fact, playing my OD-modified Strat now makes me wish I had more control over its
tonal texture-- but there's only so much of that you can do with three knobs and
a selector switch.) At first glance, the guitar may seem overly complicated--
There's a lot of depth to the controls, which is compliant with the original Gizmotronic
concept of this series of guitars. However, the basic operation is simplified
by the mix of presets and global controls. Finally, these reversible modifications
were made without significantly altering the guitar's original unique and distinctive
I have to admit that I feel a little bit guilty for having bastardized the
guitar's ingenious circuitry and clobbered its potential future collector's
value. It's kind of a paradox-- these low-impedance Les Pauls aren't very popular
because of their low-powered, low-impedance circuitry. This has resulted
in these guitars being grossly undervalued despite their sound, their playability,
the quality of their crafting, their rarity, their uniqueness, and their place
in Gibson's history. "Frankenpauling" the guitar in this way is kind of brutish,
certainly doesn't bolster its value to others, and will undeniably hurt it if
these guitars someday do become popular and I want to sell it to finance the
construction of my pyramid. What can I say? I didn't buy this guitar to sell
it: I liked it before my modifications, but I like it even more now-- plus I
had a blast working on it and learned a lot. Once you stop seeing your guitar
as an investment, you can approach it as something to be played and be
Okay, it's not pretty, but works well and reliably-- Hey, it's genuine
homemade prototype quality! I made sure that stuff was gonna stay put, soldering
the inductors' copper housings to the switch and pot. With the cover plate on,
the circuitboards are mashed into position and hemmed in by the battery box
and switch/transformer, so they really don't have anywhere to go. The cavity
later got lined with copper foil, and I added a few more wires. The circuits
are acceptably quiet, even in my electrically noisy work area. All it needs
now is a whammy bar (jez kidding). -11/08/03
A TINY ADDENDUM
Naturally, I had to explore running the PB and OD circuits in series and parallel... (My curiosity can't leave stuff like this alone.) This meant doing The Terrible Deed so I could wire a 4-pole 5-position selector switch. Diagramming this on paper was a little nightmarish, so I ended up using Adobe Illustrator so I could color code the signal routing for each of the positions.
In theory the idea seemed promising, however in practice, it didn't turn out to be such a great idea. Connecting the two circuits in parallel didn't produce a terribly different sound: The circuit's tonalities are very similar, so the effect wasn't like a layering of distinct tones. It mainly gave the OD a little more bass. Ho-hum.
In series, the effect was pretty drastic. The overdrive range was extended way beyond fuzz and I had to insert a resistor between the circuits to lower the maximum output of the PB circuit. This might have been a usable mode if it had resided better within the switch. Unfortunately, switching between it and an adjacent mode produced a horrendous pop and gain jump, so it really wasn't practical.
The 4-pole switch wasn't a total waste though. The additional positions and wiring options let me add tone control wiring options to additional PB and OD modes, so that it was possible to switch between modes that had different preset tone control mixes-- for example, PB set with simple treble cut and OD set with Decade switch and bass cut, and vice versa. It's every bit as bizarre as Gibson's original Tone Select switch, but has a lot more range in the tones you can switch between.
ALMOST EIGHT YEARS LATER, A SLIGHT RETURN
03/27/11- Here we are, almost 8 years later... I'd just installed Guitarfetish's
Treble/Mid/Bass Boost/Cut circuit in a Stratocaster,
and I thought it would be a natural to install in my Frankenpauled LPP.
The LPP's "thing" is versatile tone; the Decade switch (when
it's working as designed) alters the resonance of the higher frequency
band, so it can sound open or peaky at the extremes (listen to the sound
sample). The active 3-band EQ takes it even further in the direction
of tonal versatility.
I've had plenty of time to evaluate my original circuit design, and
to be honest, it was quite confusing, even to me, especially if I hadn't
played the guitar in a while. In particular, the 4-pole, 5-postion Tone
Selector switch setup was pretty bizarre, with 3 overdrive positions alternating
with 2 pickup booster positions. Each of these positions had different
tone control combinations tied to them (to make them different), so I
had a hard time remembering which PB position had the treble cut control
(for example), and which tied into the Decade switch. Fortunately, I had
this page to help me figure out what the hell I'd done 8 years ago! (and
that should explain why I'm doing this addendum...)
My goal was to replace the pickup booster with the EQ circuit, since
it provides a clean boost while giving the guitar true active EQ controls.
The guitar has knobs labeled "Bass" and "Treble", so it seemed a natural
and logical thing to do: The original controls had been passive treble
and bass cut, with a quirky/funky resonance feature (like a wah-wah sound)
from a combination of the inductor and capacitor in parallel.
I thought that the OD and EQ circuits in series would be cool since
the tone control for most OD circuits is just a simple treble cut, and
most Tubescreamer-like ODs cut the bass. I'd tested the EQ circuit outside
the guitar and thought that the OD->EQ combo worked pretty well. It
boosted the signal enough so that the guitar would be usable in the low
impedance mode through a regular high impedance guitar amp. Although that
mode doesn't give near the output of the high impedance mode, it was more
than adequate-- considerably louder than any other guitar with passive
circuitry. The advantage of the low impedance mode is that the Decade
switch works like it's supposed to and changes the resonance of the guitar's
voice. In high impedance mode, the Decade switch is basically a stepped
treble cut circuit. Of course, there's the thing of cascading two boost
circuits in series, which I'll talk about later... let me just say that
the OD->EQ in high impedance mode can output a tremendously loud
Figuring out my old circuitry was a daunting task, despite having documented
it here. For one thing, I'd made some changes after installing the 4-pole
switch that hadn't been document above. However, once I opened the guitar
up and started tracing and sketching the circuit, it started to make sense
(sort of). Fortunately, I didn't have to change very much-- mainly, just
the wiring of the switch (see above).
The biggest challenge was in dealing with the pots. The location of
the bass and treble pots was obvious, but I wasn't sure about the mid
cut/boost pot. I ended up putting it where the PB pot had been (at the
upper bout mike input) since it was the easiest solution and would be
conveniently located near the OD drive pot (the two seem to have a functional
association for lead sounds, IMO). I didn't want to excessively desecrate
the guitar by relocating the Decade switch, and I didn't have a knob labeled
"Mid" anyway. I just needed to thread a 3-conductor wire up
to the bout to replace the 2-conductor wire from the original microphone
jack/PB boost pot.
The GFS EQ circuit came with three 100K center detent pots with a split
shat, which aren't very common. Unfortunately, the shaft length is also
a very important parameter since if they're too short, they won't fit.
The LPP's pots are mounted on a metal shield with a stamping that mounts
them even further from the face of the guitar. There wasn't enough pot
shaft end poking through the face to mount the knobs! Although I hated
to do it (since I wasn't likely to ever come across another LPP mounting
plate), I hammered the stampings flatter so that the pots mounted closer
to the face, which gave just enough shaft length to mount the knobs. You
can always mount long shaft pots by using spacer nuts, but you can't very
easily extend the length of a pot's shaft.
Test Drive: I consider it a big improvement, since there are
fewer unintuitive "special modes" in the layout of the Tone Selector switch.
It's also nice to have true tone control in the three EQ bands. Conceptually,
that switch is now a "set & forget" switch-- one that you wouldn't want
to change while playing (due to the volume differences and the loud "pop"
between some positions).
The Bypass position works like a regular passive guitar when in high
impedance mode, and operates without a battery. However, it's not usable
in low impedance mode since the signal output is so low.
The OD and EQ positions are standalones to help fill out the 5 positions.
The OD gets tone control via the Decade switch. In high impedance mode,
it's like a stepped treble cut control, and in low impedance mode, it
acts as a resonance filter. Naturally, there isn't much OD-like gain in
the low impedance mode. The EQ mode is very similar (minus the distortion),
and the Decade switch gives additional tone shaping capabilities. The
Decade switch in both low and high impedance modes give an audibly different
type of filtering than the 3-band EQ (meaning, you can tweak the 4 knobs
and hear each knob's distinct effect).
The series modes are a little less well behaved, especially in high
impedance mode, with everything turned up. The OD->EQ mode is pretty cool
since the OD sound is easy to modify with the EQ circuit and most of the
adjustment ranges yield useful sounds. As you approach the extremes, you
get controllable feedback, and then squealing. On the other hand, the
EQ->OD mode is less useful since the EQ's gain can drive the input of
the OD circuit into some pretty nasty-sounding clipping if everything's
turned up. In low impedance mode, it's better behaved, but very hissy
and noisy. Overall, I think the best mode is low impedance in the OD->EQ
position since it gives an EQ-able overdrive sound, with the cool resonance
filter of the Decade switch.
I still need to mess around with this some more; both circuitboards
have ways to turn down their gain, and the 4-pole switch's two secondary
poles let you add resistors and capacitors between the circuits when engaging
the cascading series modes. Although not indicated in the diagram, I've
added a 60K resistor on the switch between the EQ out and the OD input;
this tamed the "everything turned up" ugliness considerably, but it still
needs some more work. More trial & error research is in order.
TWELVE YEARS LATER, ANOTHER SLIGHT RETURN
06/14/15- Further proof that you don't ever finish a project until your
lights go out. Also, evidence that tastes do change over time. I prefer
less over-the-top gain these days... but when I do that, I use a guitar
with a whammy bar.
The latest mods are a scaling back and further simplification of the
last revision: I removed the SD-1 overdrive circuit, leaving the 5-position
selector switch with just two options: EQ circuit in or out, with two
of the five positions bypassing the EQ circuit and cutting the battery
power. (It was easier to keep the 5-position switch than attempt to replace
it with the original 3-position switch.) Basically, I play this guitar
when I'm in a mellow mood, mindlessly noodling in my pursuit of the elusive
Jazz thing. The truth is, I rarely used the overdrive. For a bluesy sound,
the midrange gain from the EQ circuit produces growl comparable to that
of a passive ceramic (hot) humbucker. In passive high-impedance mode,
the output is relatively anemic, but very clean. In active low-impedance
mode with all EQ knobs at 50%, the output is about the same as passive
high-impedance mode. In passive low-impedance mode, output drops considerably.
Besides simplifying the switching modes, the change solved several problems
with the EQ+OD circuit: Switching between modes had caused an audible
pop, and it was too easy to unintentionally nudge the switch to a radically
different sound when adjusting the pots. With the revised switch wiring,
the in-circuit and bypass positions are redundant and spread far apart,
so no more unintentional nudging. It also provides a quick and easy way
to cut battery power without having to unplug the guitar. That's sheer
laziness-- I like the redundant power-cut option because I don't like
unplugging guitars when I put them in a stand.
This also eliminated the need for the overdrive pot which let me move
the midrange boost pot from the edge where the mike jack had been to the
face on the upper bout near the pickup selector switch. It's easier to
manipulate there and midrange boost is very handy for changing the tonality
from an airy mid-scooped sound to a biting blues/rock sound. A side benefit
was that it let me reinstall the gooseneck microphone jack to its rightful
place, restoring the original and unique cosmetics of this oddball guitar--
However, I left it unwired since wireless headset mikes have made that
groovy innovation obsolete. (hmmmmm.... It's actually a very good size
and place for a built-in tuner display!)
I believe that I've stayed true to my original goal for this guitar:
Turning it into a practical, usable guitar, without making irreversible
and noticeable changes to its cosmetics. Even the original interior components
are mostly intact-- the Decade switch with its cute and colorful capacitors
are untouched, and the original pots were removed with their caps and
resistors left soldered in place. Most of the changes were made to the
mode switch wiring, and unfortunately, a small amount of interior wood
was removed to fit the 4-pole switch. Using the interior photos and schematic,
it could be restored to near original functionality fairly easily, but
I doubt that will ever happen by my hands. I don't regret having removed
the gooseneck microphone feature, or having gutted the bizarre original
mode-switching feature. I've never found a compelling use for its native
low-impedance feature, but I felt the need to preserve it to occasionally
hear what the Decade switch is supposed to do. I'm just glad that the
Decade circuit works as a treble-cut circuit in high-impedance mode; it's
useful for rolling off some of the treble bite for Jazz sounds. It does
have a different effect than the EQ circuit's treble control knob, and
the capacitor values have a more usable range in active mode than they
do in passive mode (which at 10, give a deep, deep underwater sound).
Twelve years later and it's still an unreasonably heavy guitar... but
when you're playing mellow stuff, it's okay to do it sitting down.
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