
PG1free give away
Shielding is the process of covering the electric guitar's pickups with a "shield"
that keeps out interference from transformers, neon lights, TV and other amplifiers.
Single coils. Take your pickguard off to allow you to get the pickups out, or
remove them from the guitar. When you lift off the plastic pickup cover you will
see the coil. It is 5 or 6000 winds of fine wire, this coil picks up interference
like an antenna. (If your pickups have a metal cover, such as a Telecaster rhythm
pickup, it is already shielded. "Don't fix it if it ain't broke.")
Studying the pickup you will find two very small wires of the winding going over
to the lead connections. You have to be very careful around these wires, don't
break them or you will "kill" your pickup.
The most guarded shielding secret is, if you put shielding right on the coil you
cause interference with the sound. Its easy to prevent this. Just wrap the coil
with some thick tape, I use cloth tape as it is the perfect thickness.
To shield the pickup you need to wrap it with copper tape. Various rip-off companies
have offered shielding tape, selling you about 10 inches for $2.00 or more. Copper
tape about 1/4 inch wide is easy to get. Just go to any hobby or craft shop that
sells materials for STAINED GLASS. They use copper tape and you can get 20 feet
for a couple of bucks. Wrap the copper tape around the pickup coil, you may have
to go around twice to cover it all. Be careful of the two fine leads. Cut an extra
piece of copper tape. Put it across the copper tape wrapped around the pickup
coil, and over to the ground connection of the pickup's two leads. The ground
is usually the black wire, it is the wire from the pickup connected to ground
on the back of a control pot and NOT connected to the switch.
Solder the extra piece of tape to the tape wrapped around the coil and solder
it to the ground lead of the pickup. You're done! You have done all the shielding
that is necessary. (see the end for additional shielding tricks).
Humbucking pickups. These are easier, they are already wrapped with cloth tape.
All you need to do is wrap copper tape around the outside of the coils and connect
it to the metal frame of the pickup. I just solder a short piece of wire or copper
tape to the copper tape wrapped around the coils and solder the other end to the
pickup frame.
You may have replaced the stock pickups on your Les Paul with hotter Duncan, Dimarzio,
Jackson etc. pickups and it all of a sudden got noisy. It's because the cover
on the old pickups is a SHIELD. You have removed the shielding! (If you remove
the covers on the stock pickup as everyone does, you again have removed the shielding.)
Shield the pickups. Often Les Pauls don't have the strings grounded as they are
on other guitars. To fix it, drill a small hole inside the control compartment,
just above the volume control for the neck pickup. Look carefully to get the angle
right. Drill the hole to hit the stud that holds the tailpiece on the guitar.
The stud is about 1/2 inch in diameter and over one inch long. Hold the guitar
up to look and do it right. After you hit metal with your drill, run a one or
two inch small wood screw into the hole until it hits metal. Now wrap a piece
of plain wire around the wood screw and solder the other end of the wire to ground
on the back of the pot. You have installed a string ground and reduced the noise
tremendously. If you find a hole with a wire coming out of it in the guitar you
already have a string ground. Don't do anything!
ADDITIONAL SHIELDING¯I know it seems too easy, so here are some additional things
you can do to gain about 10% more noise reduction. SHIELD THE CONTROL COMPARTMENT.
Remove the controls, just unbolt them form the guitar, or remove the pickguard.
Do a real neat job of covering all the inside of the control compartment with
aluminum foil. Glue it to the sides with rubber cement and get it in there very
flat, with few wrinkles, and in one piece! If it's a Strat type with a pickguard,
come up over the edge of the wood so the shielding will make connection with the
shielding already on the pickguard. On a guitar with the controls mounted to the
guitar body, bolting them back in place makes the ground connection automatically.
SINGLE COIL PICKUPS You can replace the individual wires with a shielded cable
(RADIO SHACK #278-752). Determine which wires are the hot. These are the ones
that connects to the switch or switches. And which are the ground wires. These
are the ones that a bunched together and soldered to the back of a pot. Solder
the braided shield of your new cable to the ground connections on both sides (at
the pickup and in the control area). Solder the inside wire of the cable to the
hot connections at both ends. Replace the wires one at a time to avoid confusion.
Do a neat job and avoid any short circuits in any of this work. Now you're done!.
The guitar is quieter, cleaner and greatly improved. Best of all, you've done
it yourself.
HOP UP TRICK#1 To boost the brilliance and output of your humbucking pickup, Gibson,
Japanese made, even Seymour Duncan and Jackson pickups, there is a trick that
makes them more efficient. The 6 adjustment screws in the coil that are adjustable
extend below the pickup frame, creating an inefficient magnetic field, the "impedance"
of the coils isn't identical. Lower the screws into the coil about 1/8 inch below
the top. Take your wire cutters and cut off the part of the screws that extends
below the pickup frame. Readjust the screws so they are flush with the top of
the coil. You're done! The pickup will be brighter and stronger. You have made
it more efficient by eliminating the "eddy currents" in the magnetic field. Some
pickups don't have extended screws (some DiMarzio's) they are more efficient already.
#2 All guitars come with a 250k or, at best, a 500k volume pot. The pot puts a
"load" on the pickup's output. If you have a Strat single coil type guitar and
have added a Humbucking pickup you are losing a lot if you didn't change the volume
pot to a 500K or 1 meg pot (single coil Strats and Gibsons use a 250k pot.) The
higher the pot value the more brilliance and output you get from the pickups.
Even if you have a 500k pot you can get more from "hot pickups" by changing to
a 1 meg volume pot. It doesn't matter what kind of pot you get as the next trick
makes them all equal. Very few repairmen know anything about this and 99% of the
time won't ever think of changing the pots.
#3 To retain the highs on your volume control, and smooth out the taper. We will
add a dual network made up of a 220k resistor and a 250 pf (pico farad) capacitor.
Just tell the guy at RADIO SHACK or wherever you are what you need. You don't
need high voltage ratings. (If you can't find the parts we have a PARTS KIT for
only 99p) There are three tabs on the volume control, one tab is bent over and
soldered to the back of the pot or grounded elsewhere on the guitar. We need the
other two. Install your resistor and capacitor side by side on the other two tabs
of the volume control. (If you have a guitar with 2 volume controls, you need
a resistor and capacitor for each.) You're done! The resistor smooths out the
pots taper by "feedback," the capacitor lets the highs "escape" the pot's resistance
when you turn down. You can experiment with different resistors, 100k to 500k,
and capacitors, 47 pf to 2000 pf. Have fun, its cheap and its easy. I have given
you control of your guitar's sound.
TERMS I'VE USED
POT. The volume or tone controls. It's short for potentiometer. 250, 500, 220k.
K is electronic language for 1000 ohms. Electronic people say 500k instead of
500,000 ohms. It's how this junk is labeled in the store so you need to use their
language.
PF Pico farad. A way of measuring the value of a capacitor, more electronic language.
CAPACITOR. In general, on your guitar and amplifier a capacitor is able to affect
the tone of the signal.
RESISTOR. A resistor just affects the volume of a signal, and has no effect on
tone. Pots are measured like resistors, in ohms. And with the K symbol. You will
find the values on the back of the pot. A larger pot value means less of the signal
is "loaded" or short circuited out. Too large a pot can sound harsh (Fender ran
across this problem when they changed the volume pot on Telecasters to 1 meg.
The guitars sounded too aggressive, the "sweetness" of the Tele's lower output
pickups was reduced. Nothing says this is wrong. It was just wrong for some people.)
There is another "load resistor" at the input of your amplifier. You will learn
more about this in future TORRES ENGINEERING PROJECTS.
BONUS PROJECT - INSTALLING A MIDRANGE CONTROL Your guitar still has old fashioned
tone controls, if you are like most rock players you NEVER USE THEM. You in fact,
constantly check to see that they are on 10 all the time. The old style tone control
is just a capacitor wired to a pot shorting out some of the pickup's highs. This
was fine in 1948 when rhythm was muted and bassy. Today you need a modern tone
control to get the most out of your guitar. A new midrange control will allow
you to control the middle part of the guitar signal, leaving the bass and treble
alone. Turning down the midrange of a humbucker will get you a single coil sound.
More "crunch" and will reduce the distortion without cutting out the highs. This
is perfect for different tones, for rhythm, and for Stratocaster like sounds.
Turning down the midrange on a single coil Strat type guitar will get an acoustic
sound, transparent and glassy. Perfect for rhythm. You can fade from acoustic
to electric and retain the highs all the way. The midrange control is a "distortion
control." Most of the distortion we hear is in the midrange. You can use the control
to vary theÿ distortion right from your guitar! When turned to 10 the control
becomes inactive just like any other control Installation of a midrange at one
of the very, very few shops that possess the technology will cost $30.00
INSTALLATION GENERAL INFORMATION STRATOCASTER, OR STRATOCASTER CLONE. This is
any guitar set up like a Strat. With one volume and two tone controls. The two
tone controls work on the middle and neck pickups. It was a poor idea in 1954,
today it is ridiculous. We will convert this set up to: one volume, one tone and
one midrange control (see illustrations.) Generally we will keep one of the tone
controls, the one with the capacitor mounted on it as the tone control. Cut the
little piece of plain wire going from one tone pot to the other. The wires going
to the switch will be removed and only one will be used. (This leaves 1/2 of the
switch doing nothing, in future PERFECT GUITAR projects we will use this 1/2 switch
to get all three pickups at the same time with no bogus little switches or extra
confusing volume controls.) I like to put the midrange in the middle. It isn't
necessary, its just easier to use there. Move the pot with the capacitor to the
end position. Connect its wire to the middle tab on the volume pot. Now you have
a master tone that works on all the pickups. You should have a pot left with nothing
on it. There are three tabs on the pot. Looking at the pot from the bottom with
the tabs pointing up we will start with the tab on the far left. Install a 1.5
H (henry) inductor on the left hand tab. Solder the other end of the induct-or
to ground on the back of the same pot. Next you need a 220k resistor and a .039
mfd capacitor. Put them side by side and wrap the leads together making a little
network of the resistor and capacitor (see illustrations.) Install your resistor
and capacitor network on the middle tab of the midrange pot. Connect the other
end to the right hand tab of the volume pot. Be sure everything is shrink-wrapped
or taped to avoid any short circuits. The back of all the pots has to be connected
together for a proper ground. Now you have a master midrange control that works
on all pickups at the same time. You're done.
GIBSON TYPE This is a guitar with two tone controls again, one for each pickup.
We will convert this to a master tone and a master midrange. The tone controls
will each have a capacitor going from the tone control over to the volume control.
Some Japanese guitars have a capacitor mounted on the tone control (left hand
tab to ground) and a wire going over to the volume control. It's the same thing,
the capacitor is just in a different place in the circuit. Disconnect the wires
or capacitors from the volume pots. Save one tone" pot circuit intact. Strip off
the capacitor and wires from the other tone control pot. If you have a recent
Gibson Les Paul (since the early 70's) you will find a terminal strip in the center
of the control compartment. This is the easiest guitar to perform this conversion
on. The terminal strip has two terminals. One is grounded, connected directly
to the metal plate inside the guitar. The other is the hot connection. there is
a wire going to the enclosed jack from there (Its a black wire inside the braided
shield of the ground.) Connect your capacitor from the intact tone control to
the hot connection on the terminal strip. Now you have a master tone. You will
connect the midrange to the same place. Rewire the stripped pot as a midrange
control. Install a 1.5 H inductor on the left hand tab of the pot. This tab may
be bent over and soldered to the pot. You will have to unsolder it and lift it
away from the pot. Solder the other end of the inductor to ground on the back
of the pot. Make a little network of a .039 mfd capacitor and a 220k resistor
as in the Strat instructions. Connect one end of the network to the pot's middle
tab. Some Gibson's have the right hand tab cut off. We don't care, we don't need
it anyway. Gather the other end of your capacitor-resistor network together with
the open end of the capacitor or wire from your intact tone control. Solder them
all together in mid air, don't connect them to anything but each other (if the
tone control wire is a grounded wire, with a wire inside of a cable, leave the
plain ground wire unconnected. Now we need to connect it all to the output of
your guitar. If you have one of the Les Pauls with a terminal strip just connect
the open end of the midrange network to the same hot connection of the terminal
strip and you're done. For everyone else it's still easy. Loosen your jack and
pull it out. Find the hot connection on the jack. This is the tab connected to
the long "wiper" of the jack. There will, most likely, be a shielded cable going
to the jack. The wire in the center of the cable is connected to the hot connection.
Ok, now you have it. Solder a piece of wire to this hot connection. Solder the
other end of the wire to the bunched open ends of your tone and midrange control
network and wire/capacitor (see illustration.) Tape it up and you're done.
CHARVEL TYPE ONE VOLUME ONE TONE On a guitar with only one volume and tone you
can convert the tone to a more useful MIDRANGE control. Strip the capacitor and
the wire going over to one of the tabs of the volume control off the tone pot.
Leave the wire connecting the back of the two pots together, this is the ground.
Install a 1.5 H inductor on the left hand tab of the tone pot, connect the other
end to ground. Install the same network of a .039 mfd capacitor and 220k resistor
on the middle tab of your tone pot. Connect the other end of the network to the
right hand tab of the volume pot. You're done. You now have a midrange instead
of the useless tone control.
PARTS one .039 mfd capacitor, one 220k resistor, one 1.5 H (henry) inductor. Some
of these parts, especially the inductor are hard to find. We have a midrange kit
containing all the parts necessary including the hard to find inductor for only
£5.00. Just ask for GUITAR MIDRANGE KIT, alternatively get hold of the Super Midrange
Kit for £15- preassembled on to a pot, giving you the gradual cut in midrange
plus a midrange boost, all from a passive control (no batteries).
©copywrite 1988 Dan Torres