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Claims  |
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I claim:
1. In a pick-up for an electrical musical instrument of the type including
a body, a neck having a head, a bridge assembly connected to said body,
and a plurality of strings positioned between said head and said bridge
assembly, the improvement comprising:
first, second and third primary pick-up assemblies positioned in spaced
relationship between said neck and said bridge assembly with said second
pick-up assembly positioned between said first and third pick-up
assemblies;
fourth and fifth secondary pick-up assemblies positioned in spaced
relationship between said neck and said bridge assembly with said fourth
pick-up assembly positioned between said first and second pick-up
assemblies and said fifth pick-up assembly positioned between said second
and third pick-up assemblies;
each of said pick-up assemblies including at least one pole piece and a
coil wound therearound, the coil of said fourth pick-up assembly being
wound in a direction opposite to the coils of said first and third pick-up
assemblies and the coil of said fifth pick-up assembly being wound in a
direction opposite to the coil of said second pick-up assembly;
summing means for summing the signals from multiple ones of said pick-up
assemblies for conducting said signals to amplification means;
first switch means including an arm and three terminals, one end of said
arm being connected to an input of said summing means, said arm being
positionable in contact with any of said terminals, said first, second and
third terminals of said first switch means being connected to said coils
of said first, second and third pick-up assemblies, respectively;
second switch means including an arm and three terminals, said arm being
connected to an input of said summing means and being positionable in
contact with any of said terminals of said second switch means, said first
and second terminals of said second switch means being connected to said
coils of said fourth and fifth pick-up assemblies, respectively, said
first terminal of said second switch means being connected to said third
terminal thereof; and
means for mechanically interconnecting said arms of said first and second
switch means whereby said arms simultaneously contact said first, second
and third terminals, respectively, of said first and second switch means.
2. In a pick-up for an electrical musical instrument according to claim 1,
the improvement wherein the arms of both of said first and second switch
means have five positions and are positionable in contact with said first
terminals only, said first and second terminals, said second terminals
only, said second and third terminals, or said third terminals only of
said switch means.
3. In a pick-up for an electrical musical instrument according to claim 2,
the improvement wherein the coil of said second pick-up assembly is wound
in a direction opposite to the coils of said first and third pick-up
assemblies and the magnetic polarity of the pole piece of said second
pick-up assembly is opposite to that of said first and third pick-up
assemblies.
4. In a pick-up for an electrical musical instrument according to claim 3,
the improvement further comprising:
amplification means connected to the output of said summing means; and
third switch means including an arm and first and second terminals, said
arm of said third switch means providing the output of said pick-up and
being positionable in contact with either of said terminals thereof, said
first terminal of said third switch means being connected to the output of
said amplification means, said second terminal of said said third switch
means being connected to said arm of said first switch means whereby when
said arm of said third switch means is in contact with said second
terminal thereof, said summing means and said amplification means are
bypassed and the output of said pick-up is from said first switch means
only.
5. In a pick-up for an electrical musical instrument according to claim 1,
the improvement wherein the coil of said second pick-up assembly is wound
in a direction opposite to the coils of said first and third pick-up
assemblies and the magnetic polarity of the pole piece of said second
pick-up assembly is opposite to that of said first and third pick-up
assemblies.
6. In a pick-up for an electrical musical instrument according to claim 1,
the improvement further comprising:
a first tone control circuit connected to said arm of said first switch
means, said first tone control circuit having a first variable element;
and
a second tone control circuit connected to said arm of said second switch
means, said second tone control circuit having a second variable element;
said first and second variable elements being mechanically interconnected
for simultaneous adjustment.
7. In a pick-up for an electrical musical instrument according to claim 1,
the improvement wherein said pole pieces of said first, second and third
pick-up assemblies are magnetized and wherein said pole pieces of said
fourth and fifth pick-up assemblies are unmagnetized.
8. In a pick-up for an electrical musical instrument of the type including
a body, a neck having a head, a bridge assembly connected to said body,
and a plurality of strings positioned between said head and said bridge
assembly, the improvement comprising:
first and second primary pick-up assemblies positioned in spaced
relationship between said neck and said bridge assembly;
third and fourth secondary pick-up assemblies positioned in spaced
relationship between said neck and said bridge assembly with said third
and fourth pick-up assemblies positioned adjacent said first and second
pick-up assemblies, respectively;
each of said pick-up assemblies including at least one pole piece and a
coil wound therearound, the pole pieces of said first and second pick-up
assemblies being magnetized and the magnetic polarity of the pole piece of
said second pick-up assembly being opposite to that of said first pick-up
assembly, the coil of the second pick-up assembly being wound in a
direction opposite to the coil of said first pick-up assembly, the coil of
the third pick-up assembly being wound in a direction opposite to the coil
of said first pick-up assembly and the coil of said fourth pick-up
assembly being wound in a direction opposite to the coil of said second
pick-up assembly;
summing means for summing the signals from multiple ones of said pick-up
assemblies for conducting said signals to amplification means;
first switch means including an arm and two terminals, one end of said arm
being connected to an input of said summing means, said arm being
positionable in contact with either one or both of said terminals, said
first and second terminals of said first switch means being connected to
said coils of said first and second pick-up assemblies, respectively;
second switch means including an arm and two terminals, said arm being
connected to an input of said summing means and being positionable in
contact with either one or both of said terminals of said second switch
means, said first and second terminals of said second switch means being
connected to said coils of said third and fourth pick-up assemblies,
respectively;
means for mechanically interconnecting said arms of said first and second
switch means whereby said arms simultaneously contact said first and
second terminals, respectively, of said first and second switch means;
amplification means connected to the output of said summing means; and
third switch means including an arm and first and second terminals, said
arm of said third switch means providing the output of said pick-up and
being positionable in contact with either of said terminals thereof, said
first terminal of said third switch means being connected to the output of
said amplification means, said second terminal of said third switch means
being connected to said arm of said first switch means whereby when said
arm of said third switch means is in contact with said second terminal
thereof, said summing means and said amplification means are bypassed and
the output of said pick-up is from said first switch means only.
9. In a pick-up for an electrical musical instrument according to claim 8,
the improvement further comprising:
a first tone control circuit connected to said arm of said first switch
means, said first tone control circuit having a first variable element;
and
a second tone control circuit connected to said arm of said second switch
means, said second tone control circuit having a second variable element;
said first and second variable elements being mechanically interconnected
for simultaneous adjustment.
10. In a pick-up for an electrical musical instrument according to claim 8,
the improvement wherein said pole pieces of said first, second and third
pick-up assemblies are magnetized and wherein said pole pieces of said
fourth and fifth pick-up assemblies are unmagnetized.
11. In a pick-up for an electrical musical instrument of the type including
a body, a neck having a head, a bridge assembly connected to said body and
a plurality of strings positioned between said head and said bridge
assembly, the improvement comprising:
first and second primary pick-up assemblies positioned in spaced
relationship between said neck and said bridge assembly;
a secondary pick-up assembly positioned in spaced relationship between said
neck and said bridge assembly, between said first and second pick-up
assemblies;
each of said pick-up assemblies including at least one pole piece and a
coil wound therearound;
summing means for summing the signals from multiple ones of said pick-up
assemblies for conducting signals to amplification means;
first three-position switch means connected between said first and second
pick-up assemblies and said summing means, said first switch means
connecting said coil of said first pick-up assembly to said summing means
in a first position thereof, both of said coils of said first and second
pick-up assemblies to said summing means in a second position thereof and
said coil of said second pick-up assembly to said summing means in a third
position thereof, said first switch means connecting said coils of said
first and second pick-up assemblies in a humbucking arrangement in said
second position thereof;
second three-position switch means connected between said secondary pick-up
assembly and said summing means, said second switch means connecting said
coil of said secondary pick-up assembly to said summing means in the first
and third positions thereof and not connecting said coil of said secondary
pick-up assembly to said summing means in said second position thereof,
said second switch means reversing the polarity of said coil of said
secondary pick-up assembly when switching from said first to said third
position so as to provide a humbucking arrangement with both said first
and second primary pick-up asemblies; and
means for mechanically interconnecting said first and second switch means
for simultaneous movement to said first, second and third positions
thereof.
12. In a pick-up for an electrical musical instrument according to claim
11, the improvement wherein said coil of said second pick-up assembly is
wound in a direction opposite to said coil of said first pick-up assembly
and the magnetic polarity of the pole piece of said second pick-up
assembly is opposite to that of said first pick-up assembly.
13. In a pick-up for an electrical musical instrument according to claim
11, the improvement wherein said pole pieces of said first and second
pick-up assemblies are magnetized and wherein said pole pieces of said
secondary pick-up assembly are unmagnetized.
14. In a pick-up for an electrical musical instrument of the type including
a body, a neck having a head, a bridge assembly connected to said body and
a plurality of strings positioned between said head and said bridge
assembly, the improvement comprising:
a plurality of primary pick-up assemblies positioned in spaced relationship
between said neck and said bridge assembly;
at least one secondary pick-up assembly positioned in spaced relationship
between said neck and said bridge assembly, the number of secondary
pick-up assemblies being less than the number of primary pick-up
assemblies;
each of said pick-up assemblies including at least one pole piece and a
coil wound therearound;
summing means for summing the signals from multiple ones of said pick-up
assemblies for conducting said signals to amplification means; and
switch means for connecting said pick-up assemblies to said summing means
in a manner such that one secondary pick-up assembly is used alternately
for humbucking with two primary pick-up assemblies or two primary pick-up
assemblies are used for humbucking each other.
15. In a pick-up for an electrical musical instrument according to claim
14, the improvement wherein said pole pieces of said primary pick-up
assemblies are magnetized and wherein said pole pieces of said secondary
pick-up assemblies are unmagnetized. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pick-up for an electrical musical
instrument of the stringed type and, more particularly, to a pick-up for
an electrical musical instrument of the stringed type having greater
versatility with fewer pick-up assemblies than has been achieved
heretofore.
2. Description of the Prior Art
The present invention relates broadly to electrical musical instruments of
the stringed type. It is particularly applicable to an electrical guitar
or similar musical instrument having a plurality of stretched strings
extending across a body and a neck, between the head of the instrument and
a bridge assembly connected to the body, in which the strings are caused
to vibrate by plucking or picking same.
In order to derive an output from such an electrical guitar or other
similar electrical musical instrument, the instrument is conventionally
provided with an electromagnetic pick-up comprising a number of magnetic
elements (pole pieces) having wound therearound a conductive coil.
Typically, one such magnetic element is disposed directly beneath each
string of the instrument. The strings are constructed of a magnetizable
substance, such as steel, and, therefore, become part of the conductive
path for the magnetic lines of flux of the pole pieces. Accordingly, when
any of the strings are caused to vibrate, this causes a disturbance in the
magnetic field of the associated pole piece. This has the effect of
generating a voltage in the conductive coil, which voltage may be suitably
amplified and transmitted to a loudspeaker system.
With such an electromagnetic pick-up construction, a number of problems
exist. Electric guitars and other similar electrical musical instruments
are used in areas having strong magnetic fields from lighting fixtures,
motors, transformers, and the like, and these magnetic fields are sensed
by the pick-up as an extraneous noise source. In the United States, such
source typically has a frequency of 60 Hz, the usual power line frequency.
These magnetic fields induce voltages in the coil which are also amplified
and transmitted to the loudspeaker system, manifesting themselves in an
objectionable hum.
In order to overcome this problem, it is known to provide a pick-up for an
electrical musical instrument including a pair of identical pick-up
assemblies, each having a plurality of magnetic pole pieces and a coil,
the pick-up assemblies being positionable in parallel, spaced, closely
adjacent relationship. All of the pole pieces of one of the pick-up
assemblies have their north poles adjacent to the strings and their south
poles relatively remote from the strings whereas all of the pole pieces of
the other pick-up assembly have their south poles adjacent to the strings
and their north poles relatively remote from the strings. The coils of the
two pick-up assemblies are wound in opposite directions and the two coils
are connected either in series or in parallel. Because the direction of
current flow in each coil is governed by the magnetic polarity, the
direction of current flow in one coil is opposite to that of the other
coil for each string. However, since the directions of the windings of the
two coils are opposite, the signal induced in each coil as a result of
string vibrations is additive and the output signal is the sum of the
signals induced in each coil.
On the other hand, signals picked up by the coils from power line sources
produce currents in the coils which are independent of the magnetic
polarity and, accordingly, such power line sources produce voltages that
are in phase. However, since the coils are wound in opposite directions,
these in phase signals cancel and the output signal is the difference
between the power line signals induced in each coil. This means that any
noise from power line sources, which is otherwise manifested as an
objectionable hum, is effectively reduced or cancelled. It is for this
reason that such an arrangement is typically characterized as a humbucking
arrangement.
From the above it can be seen that whenever it is desired to have a
humbucking arrangement, it is necessary to have pairs of pick-up
assemblies. Thus, it is common for electrical musical instruments to have
two, four or six pick-ups. It would be desirable to be able to minimize
the number of pairs of pick-up assemblies while still having a humbucking
arrangement.
It is also common to sum the inputs from the different pairs of pick-up
assemblies into a preamplifier before conducting the signal from the
pick-up assemblies to the amplification system. Occasionally, the
preamplifier becomes inoperative either because of problems associated
therewith or because the batteries which run same within the instrument go
dead. In such case, only the main coils are conducted to the amplification
system and the humbucking pairs are not used. In such case, it would be
desirable to maximize the signal and to still, if possible, have a
humbucking arrangement. Other problems are further addressed herein.
SUMMARY OF THE INVENTION
According to the present invention, these problems are solved in a manner
unknown heretofore. According to the present invention, an electrical
musical instrument of the stringed type is provided with two or three
primary pick-up assemblies and, in either case, a lesser number of
additional secondary pick-up assemblies are all that is necessary to
provide a humbucking arrangement. Preferably, the secondary pick-up
assemblies are not used for signal generation. Furthermore, the pick-up
operates either with or without an instrument mounted preamplifier. With
the preamplifier in use, the signals from the primary and secondary
pick-up assemblies are summed at the preamplifier before being conducted
to the amplification system. The preamplifier may be bypassed and the
signals from the primary pick-up assemblies conducted directly to the
amplification system. When using this latter approach, the preamplifier
summing resistors are bypassed so that the signal conducted to the
amplification system is maximized, yet the possibility still exists for
humbucking.
The present pick-up also includes a dual tone control arrangement so that
the primary and secondary coils can be balanced simultaneously. Also, the
arrangement of the primary coils is such that the operation of the
secondary humbucking coils is not affected thereby.
OBJECTS, FEATURES AND ADVANTAGES
It is therefore the object of the present invention to solve the problems
encountered heretofore in providing a humbucking pick-up for an electrical
musical instrument of the stringed type. It is a feature of the present
invention to solve these problems by providing a pick-up for an electrical
musical instrument of the stringed type including a plurality of primary,
signal-producing coils and a lesser number of secondary, humbucking coils.
An advantage to be derived is a humbucking pick-up with a fewer number of
coils. A further advantage is a pick-up which can be operated with or
without a preamplifier. Another advantage is a pick-up which when used
without a preamplifier maximizes the signal applied to the amplification
system and permits humbucking, if desired. Still another advantage is a
pick-up assembly having a dual tone control.
It is another feature of the invention to solve these problems by providing
a pick-up for an electrical musical instrument of the stringed type which
can be operated with or without a preamplifier. An advantage to be derived
is a pick-up which, when used without a preamplifier, maximizes the signal
applied to the amplification system and permits humbucking, if desired.
Still other objects, features, and attendant advantages of the present
invention will become apparent to those skilled in the art from a reading
of the following detailed description of the preferred embodiment
constructed in accordance therewith, taken in conjunction with the
accompanying drawings wherein like numerals designate like or
corresponding parts in the several figures and wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial top plan view of an electrical musical instrument of
the stringed type incorporating a first embodiment of pick-up constructed
in accordance with the teachings of the present invention;
FIG. 2 is an enlarged sectional view taken along the line 2--2 in FIG. 1;
FIG. 3 is an electrical diagram of the pick-up of the instrument of FIG. 1;
FIG. 4 is an electrical diagram of a third embodiment of pick-up
constructed in accordance with the teachings of the present invention; and
FIGS. 5-7 are electrical diagrams showing the three switch positions of the
pick-up of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and, more particularly, to FIG. 1 thereof,
the present invention is illustrated as being incorporated in an
electrical guitar, generally designated 10, including a body 11, a fretted
neck 12, and a head 13 being connected to one end of neck 12, the other
end of neck 12 being connected to body 11. Tensioned between head 13 of
guitar 10 and a bridge assembly 14 are a plurality of strings 15 which
generally lie in a single plane parallel to the face of body 11. Strings
15 are constructed of a magnetizable substance, such as steel, and are
graduated in diameter in a conventional manner.
Positioned on the face of body 11 is a pick guard 16 which is typically
made from a plastic or other scratch-resistant material. Also mounted on
the face of body 11 is a switch 17, a switch 18, a volume control 19 and a
tone control 20.
In order to derive an output from guitar 10, it is provided with an
electromagnetic pick-up, generally designated 25, which forms the subject
matter of the present invention. Vibrations of strings 15, as a result of
plucking or picking the same, produce electrical signals in pick-up 25,
which signals may be suitably amplified and transmitted to a loudspeaker
system.
Referring now to FIGS. 1-3, and in accordance with a first embodiment of
the present invention, pick-up 25 includes first, second and third primary
pick-up assemblies 30, 40 and 50, respectively, which are positioned in
spaced relationship between neck 12 and bridge assembly 14 with pick-up
assembly 40 being positioned between pick-up assemblies 30 and 50. Pick-up
assemblies 30, 40 and 50 are identical and include a plurality of
identical magnetic elements (pole pieces) 31, 41 and 51, respectively,
which may be magnetized in any one of several ways known to those skilled
in the art. The number of pole pieces in each pick-up assembly is
preferrably identical and preferably the same as the number of strings 15.
However, such is not required and each pick-up assembly 30-50 can have any
number of pole pieces from one or more. According to the preferred
embodiment of the present invention, the individual pole pieces are not
magnetized, but are made from a magnetizable substance and a magnetic
field is produced by positioning a bar magnet 32, 42 and 52 in contact
with the bases of pole pieces 31, 41 and 51, respectively.
Pick-up assemblies 30, 40 and 50 are constructed and mounted in body 11 in
a conventional manner. For example, pick-up assembly 30 includes upper and
lower support plates 33 and 34, through which pole pieces 31 extend, and a
bottom support plate 35 which extends between lower support plate 34 and
magnet 32. A magnetic keeper 36 extends along the bottom surface of magnet
32. The entire assembly is positioned within a channel 21 in body 11. A
spring 37 extends between keeper 36 and the bottom of channel 21 to urge
pick-up assembly 30 upwardly. A cap 38 surrounds and contains the pick-up
assembly structure. Cap 38 and the upper ends of pole pieces 31 extend
through pick guard 16 into close proximity with strings 15. A plurality of
screws 24 extend through cap 38 and hold pick-up assembly 30 within
channel 21 in body 11. In this manner, the height of pick-up assembly 30
may be adjusted relative to strings 15.
Pick-up assemblies 40 and 50 are positioned within channels 22 and 23,
respectively, in body 11 and have parts corresponding to those discussed
in connection with pick-up assembly 30. The corresponding parts have the
same last number, with the first number being 3, 4 or 5 for pick-up
assemblies 30, 40 and 50, respectively. The only difference is that all of
pole pieces 31 and 51 of pick-up assemblies 30 and 50 have their south
poles adjacent to strings 15 and their north poles relatively remote from
strings 15 whereas all of pole pieces 41 of pickup assembly 40 have their
north poles adjacent to strings 15 and their south poles relatively remote
from strings 15. This arrangement may be reversed, the significant fact
being that pole pieces 41 are oriented oppositely to pole pieces 31 and
51.
Coils 39, 49 and 59 are formed from a large number of turns of fine
conductive wire and are wound around pole pieces 31, 41 and 51,
respectively. The wire in coils 39, 49 and 59 is insulated, such as with
varnish or lacquer, and the entire assemblies comprising the pole pieces,
the supporting plates and the coils are preferrably dipped in a suitable
varnish or lacquer. Coil 39 extends between support plates 33 and 34 and
the arrangement is similar in pick-up assemblies 40 and 50. As known in
the art, movement of strings 15, as in the strumming or playing of guitar
10, results in voltages being induced in coils 39, 49 and 59. As will be
described more fully in connection with FIG. 3, these voltages are
transferred to the input circuit of a preamplifier 80 before being
conducted to a suitable loudspeaker system.
So that the signals from coils 39, 49 and 59 are additive, coil 49 is wound
in an opposite direction to coils 39 and 59. Because the direction of
current flow in each coil is governed by the magnetic polarity, the
direction of current flow in coil 49 will be opposite to that in coils 39
and 59. However, since the direction of winding of coil 49 is opposite to
coils 39 and 59, the voltages induced in all coils as a result of string
vibrations are additive.
Pick-up 25 includes a first switch 81 which includes an arm 82 and three
terminals 83, 84 and 85 which are connected to first ends of coils 39, 49
and 59, respectively, the other ends of these coils being connected to
circuit ground. According to this embodiment of the invention, arm 82 is
part of five-position switch 17 and can be connected either to terminal
83, terminals 83 and 84, terminal 84, terminals 84 and 85, or terminal 85.
Arm 82 is also connected to a resistor 86 which is part of a summing
circuit 87 connected to the input of preamplifier 80.
Pick-up 25 also includes secondary pick-up assemblies 60 and 70 positioned
in spaced relationship between neck 12 and bridge assembly 14 with pick-up
assembly 60 positioned between pick-up assemblies 30 and 40 and pick-up
assembly 70 positioned between pick-up assemblies 40 and 50. Pick-up
assemblies 60 and 70 are referred to as secondary because they are
preferably not used for signal production and are only used for
humbucking. Pick-up assemblies 60 and 70 are similar to pick-up assemblies
30, 40 and 50 in that they include pole pieces 61 and 71, respectively,
support plates 63-65 and 73-75, respectively, and coils 69 and 79,
respectively. Pick-up assemblies 60 and 70 differ from pick-up assemblies
30, 40 and 50 in that pole pieces 61 and 71 of pick-up assemblies 60 and
70 are not magnetized and pick-up assemblies 60 and 70 preferably do not
include magnets, caps or springs. Pick-up assemblies 60 and 70 are mounted
within channels 26 and 27, respectively, in body 11 of guitar 10 and are
preferably positioned below pick guard 16 so that they are not generally
visible. The reason for this is described more fully in my co-pending
application Ser. No. 598,219, filed concurrently herewith, and entitled
Humbucking Pick-up Assembly Including an Unmagnetized, Disassociated Coil.
Pick-up assemblies 60 and 70 are used exclusively for humbucking.
Coil 69 of pick-up assembly 60 is wound in a direction opposite to coils 39
and 59 of pick-up assemblies 30 and 50, respectively, and coil 79 of
pick-up assembly 70 is wound in a direction opposite to coil 49 of pick-up
assembly 40. Because coils 69 and 79 are unmagnetized, they are not
responsive to string vibrations. On the other hand, coils 69 and 79 do
pick up noise signals which are not dependent upon a magnetic polarity.
Because of the opposite direction of winding, coil 69 is capable of
operating in a humbucking arrangement with coils 39 and 59 and coil 79 is
capable of operating in a humbucking arrangement with coil 49.
Pick-up 25 includes a second switch 91 which includes an arm 92 and three
terminals 93, 94, and 95. Arm 92 is part of switch 17 and can be connected
either to terminal 93, terminals 93 and 94, terminal 94, terminals 94 and
95 or terminal 95. Terminals 93 and 94 are connected to first ends of
coils 69 and 79, respectively, the other ends of which are connected to
circuit ground. Terminal 95 is connected to terminal 93. Arm 92 is also
connected to a resistor 88 which is part of summing circuit 87 for
preamplifier 80. Arms 82 and 92 are mechanically interconnected for
simultaneous movement under control of switch 17 of guitar 10.
In operation, it is seen that when using preamplifier 80, summing circuit
87 sums the signals from coils 39, 49, 59, 69 and/or 79 at the input of
preamplifier 80, depending upon the position of switch 17. When in its
first position, the signals from coils 39 and 69 are conducted to
preamplifier 80 and, for reasons described more fully hereinbefore, coils
39 and 69 function in a humbucking arrangement. It should also be noted
that since coil 69 is not magnetized, it does not affect the signal
producing qualities of coil 39. When moved to the second position, switch
17 conducts the signals from coils 39, 49, 69 and 79 to preamplifier 80,
with coils 79 and 49 operating in a humbucking arrangement. In the third
position, the signals from coils 49 and 79 are conducted to preamplifier
80. In the fourth position, because of the connection between terminals 93
and 95, the signals from coils 49, 59, 69 and 79 are conducted to the
input of preamplifier 80. In the fifth position, the signals from coils 59
and 69 are conducted to preamplifer 80. Thus, it is seen that coil 69
functions as a humbucker for both of coils 39 and 59 and only two
secondary coils are required rather than three.
It is highly desirable that pick-up 25 function if preamplifier 80 becomes
inoperative either because of problems associated therewith or because the
batteries that run same within guitar 10 go dead. Accordingly, the output
of preamplifier 80 is connected to a first terminal 96 of switch 18,
switch 18 having another terminal 97 which is connected directly to arm 82
of switch 81. Switch 18 has an arm 98 which is connectable either to
terminal 96 or terminal 97. When connected to terminal 96, operation is as
just described. When connected to terminal 97, the signals from coils 39,
49 or 59 are conducted directly to the amplification system, thereby
bypassing summing resistor 86 and maximizing the signal strength conducted
to the amplifier. As before, switch 17 can be placed in any one of five
positions so that the outputs of single coils or dual coils may be
conducted to the amplifier. However, it should be particularly noted that
with switch 17 in either the second or the fourth position, the signals
from coils 39 and 49 or coils 49 and 59 are summed before being conducted
to the amplifier. Since pick-up assembly 40 has its pole pieces and coils
wound opposite to pick-up assemblies 30 and 50, coil 49 operates as a
humbucker with either of coils 39 or 59. Thus, even without preamplifier
80 and secondary coils 69 and 79, humbucking can be achieved with pick-up
25.
It should also be noted that since the polarities of the pole pieces on
opposite sides of each secondary pick-up are different, the effects of the
primary coils on the secondary coils cancel and better humbucking is
achieved than if all of the pole pieces of the primary coils had the same
polarity. Since the magnetic fields of the primary coils cancel at the
secondary coils, they are freer to pick up extraneous noise sounds.
The primary coils and the secondary coils are each provided with separate
tone control circuits 100 and 104, respectively. While such tone control
circuits might not be so simple, for explanation purposes, tone control
circuit 100 is shown as including a variable resistor 101 and a capacitor
102 connected in series between arm 82 of switch 81 and circuit ground and
tone control circuit 104 is shown as including a variable resistor 105 and
a capacitor 106 connected in series between circuit ground and arm 92 of
switch 91. According to the preferred embodiment of the invention, the
variable resistors are mechanically interconnected and become the tone
control circuit 20 of instrument 10 so that the primary coils and
secondary coils may be balanced simultaneously.
According to a second embodiment of the invention, pick-up 25 includes
primary pick-up assemblies 30 and 40 and secondary pick-up assemblies 60
and 70 and switch 17 is a three-position switch where arms 82 and 92 can
be connected either to terminals 83 and 93, respectively, terminals 83 and
84 and terminals 93 and 94, respectively, or terminals 84 and 94,
respectively. This arrangement would be used where a musician wants only
two primary coils rather than three. While this embodiment does not have
the advantage of providing humbucking pairs with a lesser number of coils,
the remaining advantages of the present invention still apply.
That is, in operation, when using preamplifier 80, operation is similar to
conventional humbucking pick-up assemblies in that each primary coil has
its own secondary humbucking coil. However, when preamplifier 80 becomes
inoperative, arm 98 of switch 18 may be positioned in contact with
terminal 97 and switch 17 may be placed in its middle position where the
signals from coils 39 and 49 are summed before being conducted to the
amplifier. Since pick-up assembly 40 has its pole pieces and coils wound
opposite to pick-up assembly 30, coils 39 and 49 operate as a humbucking
pair. Thus, even without preamplifier 80 and coils 69 and 79, humbucking
can be achieved with pick-up 25.
Referring now to FIGS. 4-7, according to a third embodiment of the
invention, pick-up 25 includes primary pick-up assemblies 30 and 40 and
secondary pick-up assembly 60 and switch 17 is replaced by a switch 110.
Switch 110 is also a three-position switch but has a more complex
arrangement so that coil 69 of secondary pick-up assembly 60 can be used
as a humbucker for either coil 39 of primary pick-up assembly 30 or coil
49 of primary pick-up assembly 40.
Referring now to FIG. 4, switch 110 includes first and second switch
sections 120 and 130, respectively, which include sixe terminals 121-126
and 131-136, respectively. Switch section 120 includes a pair of switch
arms 127 and 128, first ends of which are connected to terminals 122 and
125, respectively. Coil 69 is connected between terminals 121 and 124.
Terminal 122 is connected to ground and terminal 125 is connected to
summing circuit 87. Terminal 121 is connected to terminal 126 by a jumper
129A and terminal 123 is connected to terminal 124 by a jumper 129B.
Switch section 130 includes a pair of switch arms 137 and 138, first ends
of which are connected to terminals 132 and 135, respectively. Coil 39 is
connected between terminal 134 and ground whereas coil 49 is connected
between terminal 136 and ground. Terminal 132 is connected to summing
circuit 87. A jumper wire 139A is connected between terminals 131 and 134,
a jumper wire 139B is connected between terminals 132 and 135 and a jumper
wire 139C is connected between terminals 133 and 136.
The three positions of switch sections 120 and 130 are shown in FIGS. 5, 6
and 7. With reference to FIG. 5, it is seen that in a first position of
switch 110, arms 127, 128, 137 and 138 are in contact with terminals 121,
124, 131 and 134, respectively. In this position, coils 39 and 69 are
connected to summing circuit 87. As described previously, coil 69 is wound
in an opposite direction to coil 39 so that the arrangement achieves
humbucking in the same manner as previously described.
In the position of switch 110 shown in FIG. 6, arms 127, 128, 137 and 138
are in contact with terminals 123, 126, 133 and 136, respectively. In this
position, coils 49 and 69 are connected to summing circuit 87. However,
since coil 49 is wound in an opposite direction to coil 39, it should be
noted that the terminals of coil 69 are reversed before connecting it to
summing circuit 87 so that coil 69 can function in a humbucking
arrangement with coil 49. It is this technique for reversing the leads of
coil 69 which enables it to function as a humbucker for both coils 39 and
49.
FIG. 7 shows the middle position of switch 110 where arms 127, 128, 137 and
138 are in contact with terminals 121, 126, 131 and 136, respectively. It
is immediately noted that coils 39 and 49 are connected in parallel and
that coil 69 is bypassed. It will be recalled that coils 39 and 49 are
wound in opposite directions and that the pole pieces associated therewith
are oppositely poled. For reasons explained previously, the signals from
coils 39 and 49 are additive and they comprise a humbucking arrangement.
This eliminates the necessity for using coil 69 for humbucking and it is
not so used. It is also this position of switch 110 which would be used
when arm 98 of switch 18 is in contact with terminal 97.
It can therefore be seen that this embodiment has the advantage of
providing humbucking pairs with a lesser number of coils while all of the
remaining advantages of the present invention still apply. The third
embodiment of the invention may include a dual tone control circuit as
described previously.
While the invention has been described with respect to the preferred
physical embodiments constructed in accordance therewith, it will be
apparent to those skilled in the art that various modifications and
improvements may be made without departing from the scope and spirit of
the invention. Accordingly, it is to be understood that the invention is
not to be limited by the specific illustrative embodiments, but only by
the scope of the appended claims.
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