null  null
US006376761B1
(12) Unite (1 States Patent
(10) Patent N0.:
LaMarra et al.
(54)
US 6,376,761 B1
(45) Date of Patent:
Apr. 23, 2002
MODULAR MUSICAL INSTRUMENT
6,052,472 A *
4/2000 L0
AMPLIFICATION SYSTEM
6,111,755 A
8/2000 Park ......................... .. 361/727
(76) Inventors: Frank LaMarra, 7305 CreekvieW,
West Bloom?eld, MI (US) 48322;
Bruce Egnater, 25550 Colleen St., Oak
OTHER PUBLICATIONS
Electronic Musician, Feb. 1990, “Yamaha Pro Audio—DSP
Factory”.*
Park, MI (US) 48237
( * ) Notice:
*
.
.
* cited by examiner
Subject‘ to any disclaimer, the term of this
Primary Examiner_jeffrey Donels
Patent 15 extended or adlusted under 35
(74) Attorney, Agent, or Firm—Harness, Dickey & Pierce,
U.S.C. 154(b) by 0 days.
PLC
(21) Appl. N0.: 09/495,221
(57)
(22) Filed:
A modular ampli?cation system consisting of a plurality ‘of
Jam 31’ 2000
(51)
(52)
Int. Cl.7 ........................... .. G10H 1/32; G10H 5/00
US. Cl. ........................................ .. 84/670; 381/118
(58)
Field of Search ........................ .. 84/600, 644, 670,
pre-amplifying modules for allowing a user to select at Wlll,
a particular module as desired. The modular ampli?cation
system includes a chassis Which houses a poWer supply for
supplying low and high voltages to each Of the Pre
84/746; 381/87, 1159120, 124
(56)
amplifying modules, support circuitry and interconnections
for accessing the audio and control signals as required.
Additionally, each of the pre-amplifying modules is
designed, so that it contains the circuitry required for proper
ampli?cation of various musical instruments. The pre
References Cited
U'S' PATENT DOCUMENTS
4’388’490 A *
ABSTRACT
6/1983 spector
amplifying module is selected from a vacuum tube ampli?er,
4,479,238 A * 10/1984 Spector ..................... .. 381/61
an analog and/or digital solid state ampli?er, and analog or
4,481,661 A * 11/1984 Spector
digital signal processing unit. The pre-amplifying module is
4,509,190 A *
49367185 A :
4/1985 spector _
6/1990 Yamaguchl ct a1~ ~~~~~~~~ ~~ 84/670
then inserted into the chassis by an edge connector and
suitable bolts Which alloWs ease of installation and removal.
5’142’445 A
8/1992 Sorenson et a1‘
Any combination of different pre-amplifying modules may
*
8/1995 Balsamo et al.
. .
be used Which can then be selected by a user. The modular
,488,669 A *
1/1996 Zampmi et al.
5,444,676 A
5
5,546,273 A
5 700 966 A
5,834,671 A
1.?
* 8/1996 Hams
* 12/1997 LaMana
* 11/1998 Phoenix
5,940,521 A *
t.
t
b
1. dt
k
t.
8/1999 East et al.
11 Claims, 5 Drawing Sheets
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Apr. 23, 2002
Sheet 1 of5
US 6,376,761 B1
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U.S. Patent
Apr. 23, 2002
Sheet 3 of5
US 6,376,761 B1
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Sheet 4 of5
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US 6,376,761 B1
1
2
MODULAR MUSICAL INSTRUMENT
AMPLIFICATION SYSTEM
next. The signal-routing circuitry also alloWs the signals to
be routed so that the output of one module feeds the input of
BACKGROUND AND SUMMARY OF THE
INVENTION
sor module to be physically inserted into one of the modular
The present invention relates generally to musical instru
ment ampli?ers. More particularly, the invention relates to a
modular musical instrument ampli?er system that alloWs the
musician to customiZe his or her ampli?er by selecting and
installing different modular pre-ampli?er units or effect
processor units. The units conveniently slide into the ampli
?er system chassis, so that their respective control knobs are
presented on the face of the unit for easy access. SWitching
circuitry associated With the chassis routes the music signal
presently preferred embodiment, the chassis automatically
the next. This routing option alloWs a digital-signal proces
slots and also musically inserted in the signal path. In one
senses that an inserted module is an analog or digital signal
processing unit, (as opposed to a pre-ampli?er), such that the
signal routing circuitry automatically places this unit in
10
series With the audio signal path, When selected. The signal
processing unit can be any of a variety of processing units,
including but not limited to equaliZers, compressors,
distortion, chorus, ?ange, Wah-Wah, tremolo, reverb, echo
and more sophisticated digital signal processing units.
For a more complete understanding of the invention, its
through one or more of the pre-ampli?er/effect’s units based 15
objects and advantages, refer to the folloWing speci?cation
on the user’s preference.
and to the accompanying draWings.
The musical instrument industry today offers a mind
numbing assortment of different musical instrument ampli
BRIEF DESCRIPTION OF THE DRAWINGS
?ers and effects processors from Which a musician may
choose. Each different brand and style of ampli?er has its
oWn sound and its oWn folloWing. For example, Whereas
FIG. 1 is a front vieW of a ?rst embodiment of the modular
ampli?cation system, adapted for use in a rack mount
heavy metal musicians may prefer ampli?ers of high poWer
con?guration;
With lots of raW distortion, country musicians may prefer a
less poWerful, sWeeter sound. Similarly, many blues musi
cians tend to favor more classic or vintage ampli?ers that
can be overdriven to provide a moderate level of distortion
25
sound, characteriZed by comparatively clean ampli?cation
comprising an ampli?er head and separate speaker enclo
With lots of digital signal processing. In short, there is an
ampli?er system for virtually every type of sound or music
sure;
FIG. 4 is a front perspective vieW of the ampli?cation
that is popular today.
ampli?er has heretofore been capable of providing all dif
ampli?er;
FIG. 3 is a front vieW of the modular ampli?cation
system, adapted for use in a combo ampli?cation system
or “crunch.” Techno-musicians may prefer yet another
The Wide assortment of available ampli?er and effects
processor options can make equipment shopping an emo
tional decision, fraught With compromises. Because no one
FIG. 2 is a front vieW of the modular ampli?cation
system, adapted for use in an integrated musical instrument
system, With top cover removed to shoW the internal con
?guration;
FIG. 5 is a partial perspective vieW of the rear of one of
35
ferent sounds, the musician is forced to choose. The choice
is exacerbated by the fact that a musician during his or her
career may be engaged to play a Wide range of different
the modular preampli?er units, illustrating the edge connec
tor;
FIG. 6 is a partial rear vieW of the modular ampli?cation
system, illustrating a presently preferred rear panel layout;
musical styles. Thus the musician Who buys equipment to
FIG. 7 is a block diagram of the modular preampli?er unit
perform in a heavy metal band Would ?nd himself or herself
ill-equipped if later invited to play in a blues band or country
band. Trading in old equipment to buy neW equipment is an
in accordance With the presently preferred embodiment; and
FIG. 8 is a block diagram of the chassis components of the
modular ampli?cation system of the presently preferred
expensive option.
To address this, currently several manufacturers offer a so
called “modeling” ampli?er that mimics the sounds of
embodiment.
45
different types of vintage ampli?ers using digital signal
processing technology. While modeling ampli?er technol
FIGS. 1, 2 and 3 illustrate three different physical embodi
ments of the modular ampli?cation system. In FIG. 1, the
modular ampli?cation system 10 is shoWn in a rack mount
con?guration. The con?guration includes a rack mount shell
ogy is interesting, to many a musician’s ear, this modeling
technology falls short of the mark.
The present invention addresses the foregoing problems
through a unique modular, mix-and-match system that
12 having rails 14 to Which rack mount units are attached
alloWs a musician to add to his or her ampli?cation arsenal
at far loWer cost. The modular system alloWs the musician
to add neW pre-ampli?cation modules, as needed, thereby
gaining neW sound production characteristics, at a far loWer
With screWs or bolts. For illustration purposes, the rack
55
system also advantageously alloWs the musician to “carry”
multiple different ampli?cations, Without the need to lug
several heavy ampli?ers to the gig.
In addition to providing, a convenient, modular upgrade
path, the ampli?er system of the invention offers a great deal
of ?exibility. The signal-routing circuitry associated With
chassis is controlled by the user, such as through a MIDI foot
sWitch, to route the input signal through any selective one of
mount con?guration of FIG. 1 also illustrates a poWer
ampli?er 16 and tWo outboard effects processors 18 secured
Within the rack. The empty space 20 above poWer ampli?er
16 represents available space for additional rack mount
units. In this con?guration, the output of the modular
ampli?cation system Would be fed to the input of poWer
ampli?er 16 and the output of poWer ampli?er 16 Would be
fed to a suitable speaker enclosure (not shoWn).
The preferred embodiment of the modular ampli?cation
system is designed to Work With a variety of different foot
pedals, as Will be more fully described beloW. Illustrated in
cost than buying a neW ampli?er each time. The modular
the instrument pre-amps that the user has installed. Thus the
user can, in effect, “sWitch ampli?ers” from one song to the
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENT
65
FIG. 1 is a MIDI foot pedal 22 that alloWs the musician to
control operation of the modular ampli?cation system by
pressing selected buttons on the foot pedal. Pressing the
US 6,376,761 B1
3
4
appropriate footsWitch button, the musician selects Which
preampli?er Will be used.
The integrated ampli?er embodiment of FIG. 2 includes
the modular ampli?cation system in the upper portion of the
ampli?er enclosure, as illustrated. The integrated ampli?er
Thus a signal processing module is inserted in series With the
selected pre-ampli?er module or modules, so that the signal
processing effects are available for use regardless of Which
pre-ampli?er module the musician has selected.
The pre-ampli?er modules can be based on either solid
state or vacuum tube design. Many vintage ampli?ers
employ vacuum tube circuitry, and a large number of
musicians still prefer vacuum tube circuitry for the Warm
has a self-contained poWer ampli?er and a speaker or
speakers. The speakers are disposed behind grill 24 and the
poWer ampli?er may be integrated With or attached to the
modular ampli?cation system. For illustration purposes, a
front panel on/off sWitch 26 and an additional poWer ampli
?er gain control knob 28 are illustrated. Although not
required, these additional controls may be desired in some
distortion that this circuitry provides. Pre-ampli?er module
42 thus illustrates hoW vacuum tube circuitry may be
incorporated into the modular packaging. Pre-ampli?er
module 42 employs tWo vacuum tubes 56 and 57 that are
attached With tube sockets to a stand-off circuit board 60. To
con?gurations.
minimiZe hum, the vacuum tubes may be shielded With a
The integrated ampli?er system illustrated in FIG. 2
suitable cylindrical metal shield as at 62. The shield has been
includes a simple on/off push-button sWitch 30 that is 15 removed from vacuum tube 56 to reveal the vacuum tube.
connected through an input on the rear panel of the modular
The modular pre-ampli?er units (and effects processors
ampli?cation system. By momentarily pressing sWitch 30,
units) attach to the chassis 64 of the modular ampli?cation
system 10 using edge connectors. The edge connector asso
ciated With slotted opening 54 is shoWn at 66. The edge
connector is designed to receive the posterior edge of the
the musician is able to control the operation of the modular
ampli?cation system. More speci?cally, the presently pre
ferred embodiment of the ampli?cation system alloWs the
musician to install up to four modular pre-ampli?cation
circuit board associated With a modular unit, so that the
units or modular effects processor units. These four units are
shoWn at 40, 42, 44, and 46 in FIG. 2. By momentarily
activating the push-button sWitch 30, the musician can cycle
from one pre-ampli?cation unit to the neXt, thereby instantly
changing Which preampli?er Will be used.
25
header connectors, ribbon connectors and the like. FIG. 5
shoWs hoW the circuit board of a modular unit is provided
With a male edge portion 68 that Will insert into the female
FIG. 3 illustrates a third embodiment of the modular
ampli?cation system 10, in Which the ampli?cation system
is mounted in a separate head unit 50 that sits atop the
edge connector 66.
The edge connector supplies poWer to the modular units
and also makes appropriate contact for sending and receiv
ing the audio signals and any necessary data or control
signals. Preferably the edge connector is Wired so that
speaker enclosure cabinet 52. Aside from having the ampli
?er section and speaker enclosure section disposed in sepa
rate cabinets, the basic con?guration of the embodiment of
FIG. 3 is electronically the same as the embodiment of FIG.
2.
The modular ampli?cation system 10 is shoWn in greater
35
certain contacts are assigned to certain functions (such as
poWer supply functions, audio signal functions, MIDI data
functions, on/off functions, and the like).
detail in FIG. 4. Speci?cally, a rack mount embodiment is
illustrated in FIG. 4. It Will, of course, be understood that the
other embodiments Would similarly fabricated. In the
embodiment illustrated in FIG. 4 the top panel of the
ampli?er system has been removed to reveal the internal
Typically a vacuum tube circuit Will require a loW voltage
(eg 6 volts or 12 volts) to supply the vacuum tube heaters
and a high voltage (eg 300 volts DC) to supply the vacuum
tube plate and other associated biasing circuitry. A transistor
pre-ampli?er unit or digital signal processing unit may
components. In addition, the top cover of pre-ampli?er
module 42 has also been removed to reveal the internal
components of that unit. Further note that no pre-ampli?er
unit is installed in the upper right-hand corner, thereby
revealing one of the elongated slotted openings 54.
appropriate circuit board traces make contact With the edge
connector 66. Although edge connectors are presently
preferred, other suitable mulit-pin connectors may be used.
Such connectors include, but are not limited to, multi-pin
require other voltages as Well. All of these voltages are
45
preferably generated by a common poWer supply using
suitable voltage regulators to supply the needed voltages. A
digital device, such as a signal processing unit or a transis
toriZed pre-ampli?er device Would not require the same
Each slotted opening is siZed to receive a modular unit
similar to those shoWn at 42, 44, and 46. In the illustrated
embodiment, modular units 42 and 44 are pre-ampli?er units
voltages as the vacuum tube devices and hence Would not
having Gain, Bass, Middle, Treble and Master control
those higher voltages. Alternatively, each individual module
knobs. Module 46 is a digital signal processor unit. The
slotted opening 54 may be ?lled With a screW-in or snap-in
can have its oWn voltage regulator circuitry to convert the
make contact With the edge connector contacts carrying
supply voltages to the proper voltages required.
The pre-ampli?er circuits and the digital signal processing
protective cover When no modular unit is installed. The same
is true for the other locations.
The musician has complete ?exibility as to Which pre
ampli?er modules to insert into Which of the four locations.
In one embodiment, one of the four slotted openings is
designated to receive either a pre-ampli?er module or an
effects processor module. In FIG. 4 the loWer right-hand
55
slotted opening (carrying module 46) is designated for this
dual function. Of course, any of the four slotted openings
could be designed to provide the dual function capability.
In an alternate embodiment, the circuitry is designed to
accept either a pre-ampli?er module or a signal processing
module at any of the four locations. In this alternate
embodiment, the circuitry senses Which type of module has
been installed and routes the audio signals appropriately.
circuits typically include at least one audio input and at least
one audio output. These inputs and outputs are also provided
at the appropriate edge connector terminals. If desired, the
edge connectors can be con?gured so that digital signal
processing units are inserted in the audio signal chain (in
series With a pre-ampli?er). This may be done by assigning
certain contacts of the edge connector to the signal insert
function. Other contacts used by the pre-ampli?er units
Would connect the input and output of the pre-ampli?er With
the input and output of the modular ampli?cation system.
For more details on signal routing, refer to the circuits
65
description beloW.
Pre-ampli?er units based on vintage ampli?er designs
typically have fairly simple feature sWitching requirements.
US 6,376,761 B1
5
6
For example, a vintage pre-ampli?er circuit may employ a
signal push button switch to engage or disengage a “Bright”
toggle sWitch, or to select betWeen “Rhythm” and “Lead”
channels. The sWitching signals to control these features
provided. Because consumer grade and commercial grade
effects processors may have different input signal level
requirements, a HI/LO toggle sWitch 92 is provided in the
may be supplied by a simple momentary push-button sWitch
match the signal requirements of the outboard signal pro
cessing equipment he or she is using.
The modular ampli?cation system is able to supply output
effects loop. The musician can sWitch this toggle sWitch to
Which is connected through suitable contacts on the edge
connector. More sophisticated digital modeling ampli?ers
and digital signal processing units typically require more
complex control mechanisms. The presently preferred
embodiment supports MIDI control. MIDI control signals
signals that are derived either after the effects loop or before
10
are supplied over suitable contacts of the edge connector to
devices that utiliZe MIDI signals. In this Way, a MIDI foot
thus provides a dry signal (not affected by the effects loop).
pedal can be used to change modeling ampli?er character
istics or digital signal processing characteristics either
betWeen songs or as the musician is playing.
the effects loop. The output jacks 94 are “post loop” and thus
provide an audio output signal that is affected by any devices
attached into the effects loop. Output 96 is “preloop” and
Turning noW to the circuit diagrams of FIGS. 7 and 8, a
further explanation of the preferred signal routing circuitry
15
The modular ampli?cation system is designed With ?ex
ibility in mind. Thus, the musician can select the pre
ampli?er units of choice (and also the digital signal pro
cessing units of choice) and conveniently insert them into
Will noW be described. Referring to FIG. 7, an exemplary
pre-ampli?er module in accordance With the invention
derives a plurality of input signals (fed to edge card con
nector 68) from the modular ampli?er system chassis. In the
presently preferred vacuum tube pre-ampli?er circuit, those
input signals include, a control input signal on lead 100, and
the slots provided on the front panel of system 10. Each
modular unit provides its oWn potentiometer controls and
sWitches that are used to control the basic pre-ampli?er
audio input signal on lead 102, and audio output signal on
lead 104 and high and loW poWer supply voltages on leads
functions (or digital signal processing functions, as the case
may be). Although the pre-ampli?er units illustrated in FIG.
4 have the identical con?guration: Gain, Bass, Middle,
106 and 108, respectively.
The input and output signals are fed through audio
25
sWitches 110 and 112 that are activated by a logic signal on
Treble, Master, the illustration is not intended as a limitation.
control input lead 100. When the pre-ampli?er module is
Rather, the pre-ampli?er units can have any con?guration as
sWitched into operation, a control signal on lead 100 closes
desired to provide the functionality of the ampli?er it is
designed to emulate.
After the musician has inserted the pre-ampli?er units of
choice into the system 10, the ampli?er is ready for use. The
musician plugs a musical instrument into input jack 70 and
sWitches 110 and 112, causing the audio input signal to be
fed into the gain processing stages 114 via sWitch 110. The
the audio input signal is automatically routed to Whichever
pre-ampli?er unit is currently active. The active pre
ampli?er unit may be selected by depressing the channel
same control signal also sWitches audio sWitch 112 into
conduction, thereby feeding the output of the gain process
35
select button 72 on the front panel or by using a foot sWitch.
Each time the button is pressed, the system steps to the next
so that the pre-amp stage can be overdriven While still
maintaining a moderate volume level. The preferred tone
control section includes a Bass control 120, a Mid-range
vided With an assortment of output jacks on the rear panel,
as illustrated in FIG. 6. In this regard, FIG. 6 illustrates one
control 122 and a Treble control 124.
Note that the audio sWitches 110 and 112 isolate both the
possible embodiment. Depending on the actual implemen
tation (rack mount, integrated ampli?er, combo ampli?er).
45
input and the output of the audio gain and processing stages
14. This is done to reduce crosstalk and noise that might
otherWise occur due to the close proximity of the pre
ampli?er sections Within the chassis.
The circuitry associated With chassis 64 is illustrated in
FIG. 8. The poWer supply 140 supplies both high voltage
(HV) and loW voltage (LV) poWer that are respectively
Ground loops are caused When tWo or more pieces of audio
supplied to the HV and LV pins of the edge connectors 66.
In FIG. 8 the individual edge connectors associated With the
equipment are connected through plural ground connections
producing an undesirable buZZ or hum in the audio output.
MIDI Input and Thru jacks are provided at 84 for con
nection of a MIDI control pedal such as pedal 22. The more
speci?cally, the preferred embodiment provides both input
and output gain controls, designated as gain control 116 and
master control 118. In many popular pre-ampli?er circuits,
it is common to provide both gain and master gain controls,
pre-ampli?er unit installed. Any empty slots are simply
skipped as the channel select button is pressed.
The modular ampli?cation system 10 is preferably pro
The rear panel con?guration may differ.
Referring to FIG. 6, the poWer sWitch 80 turns the
modular ampli?cation system on and off, While the ground
lift sWitch 82 disconnects the ground associated With the
audio signal path. The ground lift sWitch is thus used to
eliminate ground loops that are sometimes encountered.
ing stages 114 to the audio output lead 104.
The audio gain and processing stages have suitable poten
tiometer controls to adjust the ampli?er gain and tone. More
55
four slotted openings have been further designated 66a—d. In
the illustrated embodiment, the fourth slot (associated With
simple push button sWitch (such as push button 30) (FIG. 2)
edge connector 66a) serves a dual purpose. It can accom
modate either a pre-ampli?er module or an effects processor
is connected to foot sWitch input jack 86. Although the
preferred embodiment provides an input jack 70 on the front
module.
The audio input signal is fed as illustrated at 142 from
panel (FIG. 4), an additional input jack may be provided as
both the front input jack 70 and the rear input jack 88
through a 20db gain stage 144. This gain stage, in turn, feeds
the four edge connectors With the audio input signal.
The control logic circuit 146, Which may be connected to
at 88 on the rear panel (FIG. 6).
The remaining inputs and outputs featured on the back
panel may be used to connect to poWer ampli?ers (such as
ampli?er 16 of FIG. 1) or to other outboard effects proces
sors (such as processors 18 of FIG. 1). The preferred
embodiment is designed to send and receive audio signals to
an effects loop. Thus suitable send and return jacks 90 are
65
the foot sWitch input 86 and also to the MIDI processor 150.
MIDI processor 150 receives MIDI input signals on the
MIDI input jack 84, decodes those signals, and supplies a
control logic signal to the control logic circuit 146. This Way
US 6,376,761 B1
8
7
a plurality of modular preampli?er units for amplifying a
musical instrument input signal, at least one of said
either the simple push button foot switch or a MIDI control
foot switch can provide switching instructions to the control
preampli?er units having ampli?cation and sound col
logic circuit 146.
The control logic circuit, in turn, supplies control input
oration properties not shared by at least one other of
said preampli?er units, each of said preampli?er units
signals to the edge connectors 66 to be supplied to the
modules that are plugged into the respective edge connec
having a second connector for an engagement with one
of said ?rst connectors when said preampli?er unit is
inserted into one of the modular slots; and
tors. If desired, the MIDI processor 150 can supply an
additional MIDI signal on lead 152, which may be routed to
an appropriate terminal on the edge connector. In this regard,
edge connector 66d includes pin 154 that supplies the MIDI
control signal. This control signal may be used to change the
settings of a MIDI device plugged into that slot. Although
only edge connector 66d is illustrated with the MIDI signal
present, it will be apparent that the MIDI signal can be
supplied to all edge connectors, if desired.
Each of the edge connectors 66 provides an audio output
a signal routing circuitry coupled to said plurality of ?rst
connectors for selecting an output from one of the
preampli?er units in order to feed the output signal into
a power ampli?er.
15
terminal that routes the audio signal over an audio summing
bus 160 to the unity gain mixer/buffer ampli?er 162. This
buffer ampli?er, in turn, supplies the audio output signal to
the effects send jack 90a and to the pre loop output jack 96.
The effects return jack 90b couples the effects return signal
2. The system of claim 1 wherein said chassis is adapted
to be secured to a pair of mounting rails.
3. An integrated musical instrument ampli?er having a
power ampli?er and at least one speaker disposed in a
common cabinet, and further comprising the modular musi
cal instrumentation ampli?cation system according to claim
1, said system being disposed in said common cabinet and
being coupled to said power ampli?er.
4. Amusical instrument combo ampli?er head comprising
through a wet/dry miX control 164 that is used to blend the
amount of the effects processed signal with the dry or
unprocessed signal. The wet/dry miX control 164 is provided
with a suitable control knob illustrated in FIG. 4 at 164a. 25
a power ampli?er disposed in a ?rst cabinet, said power
ampli?er having at least one output terminal for coupling to
at least one speaker eXternal from said ?rst cabinet; and
further comprising the modular musical instrumentation
ampli?cation system according to claim 1, said system
being disposed in said ?rst cabinet and being coupled
The miX control supplies output signals to the unity gain
mixer/buffer 166, which in turn provides the post loop
to said power ampli?er.
5. The system of claim 1 wherein said signal routing
output signal to jack 94. The unity gain mixer/buffer ampli
?ers 162 and 166 are preferably provided with a level
circuitry includes a control logic circuit that causes one of
control knob (shown in FIG. 4 at 166a). This control knob
adjusts the overall master gain to control the level of the
signal present on all of the output jacks.
Although it is not necessary to provide a power ampli?er
said plurality of modular preamplifer units to be selectively
connected to said output.
6. The system of claim 1 further comprising at least one
stage on chassis 64, such a stage can be added if desired. In 35 modular signal processing unit removeably inserted into at
least one of said modular slots, said processing unit having
FIG. 8 the power ampli?er is shown at 200. It receives input
a third connector that engages one of said ?rst connectors
signals from the unity gain mixer/buffer ampli?ers 162 and
when said processing unit is inserted into one of the modular
slots.
7. The system of claim 6 wherein said preampli?er units
166 and supplies an output to a suitable speaker cabinet. The
power ampli?er 200 can be mono, stereo or more channels,
as desired.
From the foregoing it will be appreciated that the modular
ampli?cation system of the invention provide a great deal of
?exibility and versatility. The musician can, in effect, build
a custom musical instrument ampli?er having a variety of
different performance characteristics without the need to
each de?ne an audio signal path and wherein said signal
routing circuitry couples said processing unit in the audio
signal path of at least one of said preampli?er units.
8. The system of claim 6 wherein said modular signal
45
purchase a multiple complete ampli?er systems. The inven
least one MIDI input port for receiving MIDI control signals
and for routing said control signals to said processing unit.
tion thus helps the musician enhance his or her playing styles
and musical opportunities without unduly taXing the budget.
10. The system of claim 1 further comprising at least one
power supply associated with said chassis that delivers
electric power at least one supply voltage to said ?rst
connectors and wherein said modular preampli?er units
receive operating power by making contact with said ?rst
While the invention has been shown in its presently
preferred embodiments, it will be appreciated that the inven
tion is capable of modi?cation without departing from the
spirit of the invention as set forth in the appended claims.
What is claimed is:
1. A modular musical instrument ampli?cation system
comprising:
a chassis that de?nes a plurality of modular slots and
supports a plurality of ?rst connectors each associated
with one of said modular slots, each of said modular
slot, having a ?rst connector;
processing unit is connected to a MIDI switch.
9. The system of claim 8 wherein said chassis includes at
connectors.
55
11. The system of claim 1 wherein said signal routing
circuitry includes at least one effects loop circuit whereby
external signal processing units are coupled in the audio
signal path to alter said output signal.
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