JP2008283581

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2008283581
PROBLEM TO BE SOLVED: In a multi-channel amplifier having amplification means for
headphones, when headphones are not used, the audio signal path to the front speaker is not
adversely affected by the audio signal path to the headphone, and the sound output from the
front speaker is high. Provided is a multi-channel amplifier that realizes low-cost implementation
of sound quality. SOLUTION: A multi-channel amplifier according to the present invention has a
buffer circuit from a first input terminal 1 for outputting a front channel signal FL / FR to a front
speaker when headphones are not connected to an output terminal for headphones. The audio
signal path from the switch IC 9 to the first volume adjustment means 3a, the buffer circuit 10b
and the first amplification means 4a to the front speaker output terminal 6 is not electrically
connected to other audio signal paths The switch IC and the first to third switches are on / off
controlled by the control means 5 so that [Selected figure] Figure 1
Multichannel amplifier
[0001]
The present invention relates to a multichannel amplifier comprising amplifier means for
headphones.
[0002]
A conventional multichannel amplifier will be described.
10-05-2019
1
FIG. 3 is a circuit diagram showing a schematic configuration of a conventional multi-channel
amplifier. The conventional multi-channel amplifier includes a front channel volume adjustment
unit 3a, a surround channel volume adjustment unit 3b, a front channel amplification unit 4a, a
surround channel amplification unit 4b, a headphone amplification unit 4c, and a control unit.
And 5, a front speaker output terminal 6, a surround speaker output terminal 7, a headphone
output terminal 8, and switches SW1 to SW3.
[0003]
The front channel volume adjustment means 3a receives the front channel signal FL / FR, which
is an analog audio signal input via the input terminal 1, adjusts the level of the front channel
signal FL / FR, and amplifies the front channel Output to means 4a. The front channel
amplification means 4a amplifies the front channel signal FL / FR and outputs it to the front
speaker terminal 6 through the switch SW1. Then, the front channel signal FL / FR is output to
the front speaker connected to the front speaker output terminal 6 and converted into sound.
[0004]
The surround channel volume adjustment means 3b receives the analog surround channel signal
SL / SR input via the input terminal 2, adjusts the level of the surround channel signal SL / SR,
and outputs the surround channel signal SL / SR to the surround channel amplification means
4b. Do. The surround channel amplification means 4b amplifies the surround channel signals SL
/ SR and outputs the surround channel signals SL / SR to the surround speaker output terminal 7
via the switch SW2. Then, the surround channel signals SL / SR are output to the surround
speakers connected to the surround speaker terminal 7 and converted into sounds.
[0005]
The headphone amplification means 4c has its input end connected in parallel with the front
channel amplification means 4a at a stage subsequent to the front volume adjustment means 3a,
and the front channel signal FL / FR adjusted in level by the front channel volume adjustment
means 3a. Is input. The headphone amplification means 4c amplifies the input front channel
signal FL / FR and outputs the amplified front channel signal FL / FR to the headphone output
terminal 8 through the switch SW3. Then, the front channel signal FL / FR is output to the
headphones connected to the headphone output terminal 8 and converted into sound.
10-05-2019
2
[0006]
When the headphones are connected, the headphone output terminal 8 outputs that the
headphones and the headphone output terminal 8 are connected to the control means 5 as a
connection signal. The control means 5 detects a connection signal output from the headphone
output terminal 8 and controls the switches SW1 to SW3 on and off based on the connection
signal.
[0007]
When no headphone is connected to the headphone output terminal 8, the control means 5
performs the switches SW1 and SW2 so that the front channel signal FL / FR or the surround
channel signal SL / SR is output to the front speaker or the surround speaker, respectively. On
and the switch SW3 off. Further, when headphones are connected to the headphone output
terminal 8, the control means 5 turns off the switches SW1 and SW2 and turns on the switch
SW3 so that the front channel signal FL / FR is output to the headphones.
[0008]
In such a conventional multi-channel amplifier, even when the headphone is not connected to the
headphone output terminal 8, the headphone amplification means 4c functions as the front
channel amplification means after the front channel volume adjustment means 3a. Since it is in a
state of being connected in parallel with 4a, the sound quality is deteriorated by the fact that the
input impedance of the front channel amplification means 4a drops or the wiring to the
headphone amplification means 4c becomes an inductor component. There's a problem.
[0009]
Therefore, relays are respectively provided in front of the front channel amplifier 4a and the
headphone amplifier 4c, and when the headphones are not connected to the headphone output
terminal 8, the relays are controlled to turn on and off and the front channel amplifier 4a and the
headphones are controlled. There is a method of solving the above-mentioned problem by
electrically disconnecting the amplifier 4c.
10-05-2019
3
However, relays are expensive and cost-prone.
[0010]
Japanese Patent Application Laid-Open No. 10-13987
[0011]
The present invention has been made to solve the above-mentioned problems of the prior art,
and its object is to provide a multi-channel amplifier having amplification means for headphones,
even when headphones are not used. An object of the present invention is to provide a multichannel amplifier that realizes high-quality sound output from a front speaker without the audio
signal path to a speaker being adversely affected by the audio signal path to a headphone.
[0012]
A multi-channel amplifier according to a preferred embodiment of the present invention has a
first input terminal to which a front channel signal is input, a second input terminal to which a
surround channel signal is input, and the front channel signal. First volume adjustment means for
adjusting the level of the channel signal; second volume adjustment means for receiving the front
channel signal or the surround channel signal and adjusting the level of the front channel signal
or the surround channel signal; Connected to the first volume adjusting means, which is
connected to the first volume adjusting means, amplifies the front channel signal supplied from
the first volume adjusting means and outputs the amplified signal to the front speaker;
Amplifying the surround channel signal supplied from the second volume adjustment means A
second amplification means for outputting to a round speaker, and the second volume
adjustment means connected in parallel with the second amplification means to amplify the front
channel signal supplied from the second volume adjustment means A third amplification means,
a headphone output terminal connectable to headphones and outputting the front channel signal
supplied from the second amplification means, and the first volume adjustment from the first
input end Means and first switch means for switching a first path leading to the front speaker
through the first amplification means to the connected state or the disconnected state; and the
second volume control means from the first input end A second switch means for switching the
second path to the connection state to the connection state or the disconnection state, and a third
path from the second input end to the second volume adjustment means the connection state or
the disconnection Shape Third switch means for switching to the second sound source, and
fourth switch means for switching the fourth path from the second volume adjustment means to
the surround speaker via the second amplification means to the connected state or the nonconnected state; A fifth switch means for switching a fifth path from the second volume
adjustment means to the headphone output terminal via the third amplification means to the
10-05-2019
4
connection state or the disconnection state; and the headphone is the headphone Control means
for controlling switching of the connection state or non-connection state of the first to fifth paths
based on whether or not the output terminal is connected to the output terminal; When the
headphones are not connected, the first and second switch means are controlled such that the
first path is in the connection state and the second path is in the disconnection state.
[0013]
In a further preferred embodiment, the first switch means includes a switch unit for switching
the connection between the first input end and the first volume adjustment means to a connected
state or a disconnected state, and for the headphone When the headphone is connected to the
output terminal, the first path, the third path, and the fourth path are not connected, and the
second path and the fifth path are connected. To control the switch unit and the second to fifth
switches.
[0014]
In a further preferred embodiment, a first or second buffer circuit is connected between the first
input end or the second input end and the switch IC, and the switch IC and the first volume
adjustment A third or fourth buffer circuit is connected between the means or the second volume
adjusting means.
[0015]
According to the present invention, in a multi-channel amplifier having amplification means for
headphones, the audio signal path to the front speakers and the audio to the headphones when
the headphones are not used (that is, when sound is output from the front speakers). By
disconnecting from the signal path, the audio signal path to the front speaker is not affected by
the signal path to the headphone, and a multi-channel amplifier is realized to realize high-quality
sound output from the front speaker It is possible to
[0016]
The following describes a multi-channel amplifier according to preferred embodiments of the
present invention, but the present invention is not limited to these embodiments.
The same or corresponding parts in the drawings are denoted by the same reference numerals
and their descriptions are incorporated.
10-05-2019
5
[0017]
First, referring to FIG. 1, the schematic configuration of the multi-channel amplifier of the present
invention will be described.
FIG. 1 is a circuit diagram showing a multi-channel amplifier according to a preferred
embodiment of the present invention.
[0018]
The multi-channel amplifier includes a first input terminal 1, a second input terminal 2, a first
volume control unit 3a, a second volume control unit 3b, a first amplification unit 4a, and a
second A surround speaker to which a front speaker output terminal 6 to which an amplification
means 4b, a third amplification means 4c, a control means 5, a front speaker (not shown) are
connected, and a surround speaker (not shown) are connected And a headphone output terminal
8 to which headphones (not shown) are connected, switches SW1 to SW3, a switch IC 9, and
buffer circuits 10a to 10d.
[0019]
The first input terminal 1 receives the front channel signal FL / FR which is an analog audio
signal from the outside, and the second input terminal 2 receives the surround channel signal SL
/ SR which is the analog audio signal from the outside Be done.
[0020]
The first volume adjustment means 3a adjusts the level of the front channel signal FL / FR
inputted from the first input terminal 1 and outputs the same to the first amplification means 4a.
In the present embodiment, the first volume adjustment means 3a includes an operational
amplifier OP1, and the output end of the operational amplifier OP1 is connected to the output
end of the volume adjustment means 3a.
10-05-2019
6
The positive phase input terminal of the operational amplifier OP1 is connected to the slider of
the variable resistor VR1 connected to the input end of the volume control means 3a and
grounded.
The negative phase input terminal of the operational amplifier OP1 is connected between the
output end of the operational amplifier OP1 and the output end of the volume control means 3a,
is grounded, and is connected to the slider of the variable resistor VR2, and the level adjusted
front channel signal FL / FR is input as a feedback signal.
[0021]
The second volume adjustment means 3b adjusts the level of the front channel signal FL / FR
inputted from the first input terminal 1 or the surround channel signal SL / SR inputted from the
second input terminal 2, The signal is output to the second amplification means 4b or the third
amplification means 4c.
In the present embodiment, the second volume adjustment means 3b includes an operational
amplifier OP2, and the output end of the operational amplifier OP2 is connected to the output
end of the volume adjustment means 3b.
The positive phase input terminal of the operational amplifier OP2 is connected to the slider of
the variable resistor VR3 connected to the input end of the volume control means 3b and
grounded.
The negative-phase input terminal of the operational amplifier OP2 is connected between the
output end of the operational amplifier OP2 and the output end of the volume adjustment means
3b and is connected to the slider of the variable resistor VR4 grounded and the level-adjusted
front channel signal An FL / FR or surround channel signal SL / SR is input as a feedback signal.
[0022]
The first amplification means 4a is connected to the subsequent stage of the first volume
adjustment means 3a, and amplifies the front channel signal FL / FR level-adjusted by the first
10-05-2019
7
volume adjustment means 3a to the front speaker output terminal 6 Output. The second
amplification means 4b is connected to the subsequent stage of the second volume adjustment
means 3b, and amplifies the surround channel signal SL / SR level-adjusted by the second volume
adjustment means 3b to the surround speaker output terminal 7 Output. The third amplification
means 4c is connected in parallel with the second amplification means 4c at the subsequent
stage of the second volume adjustment means 3b, and the front channel signal FL / FR adjusted
in level by the second volume adjustment means 3b is It is amplified and output to the
headphone output terminal 8.
[0023]
The switch SW1 is for switching the output path from the first amplification means 4a to the
front speaker to the connected state or the disconnected state. In other words, the switch SW1 is
connected between the first amplification means 4a and the front speaker output terminal 6, and
the front channel signal FL / FR output from the first amplification means 4a is the front speaker
output terminal 6 To allow or block the supply of That is, when the switch SW1 is turned on, the
front channel signal FL / FR output from the first amplification means 4a is supplied to the front
speaker output terminal 6, and when the switch SW1 is turned off, the front channel signal FL /
FR The supply to the speaker output terminal 6 is blocked.
[0024]
The switch SW2 is for switching the output path from the second amplification means 4b to the
surround source in the connection state or the non-connection state. In other words, the switch
SW2 is connected between the second amplification means 4b and the surround speaker output
terminal 7, and the surround channel signal SL / SR output from the second amplification means
4b is the surround speaker output terminal 7 To allow or block the supply of That is, when the
switch SW2 is turned on, the surround channel signal SL / SR output from the second
amplification means 4a is supplied to the surround speaker output terminal 7, and when the
switch SW2 is turned off, surround of the surround channel signal SL / SR The supply to the
speaker output terminal 7 is blocked.
[0025]
The switch SW3 is for switching the output path from the third amplification means 4c to the
10-05-2019
8
headphone to the connected state or the disconnected state. In other words, the switch SW3 is
connected between the third amplification means 4c and the headphone output terminal 8, and
the front channel signal FL / FR output from the third amplification means 4c is supplied to the
headphone output terminal 8. To allow or block the supply of That is, when the switch SW3 is
turned on, the front channel signal FL / FR output from the third amplification means 4c is
supplied to the headphone output terminal 8, and when the switch SW3 is turned off, the
headphone for the front channel signal FL / FR is output. The supply to the output terminal 8 is
blocked.
[0026]
The switch IC 9 is connected between the first input end 1 or the second input end 2 and the first
volume adjustment means 3a or the second volume adjustment means 3b, and the first input end
1 to the first input end 1 The input path of the volume adjustment means 3a is switched to the
connection state or disconnection state, the input path from the first input terminal 1 to the
second volume adjustment means 3b is switched to the connection state or disconnection state,
and the second input end This is for switching the input path from 2 to the second volume
adjustment means 3b to the connected state or the disconnected state.
[0027]
The switch IC 9 includes switches SW4 to SW6.
The switch SW4 is connected between the first input terminal 1 and the first volume adjustment
means 3a, and the input path from the first input terminal 1 to the first volume adjustment
means 3a is connected or not connected Switch to In other words, the switch SW4 is for
permitting or blocking the supply of the front channel signal FL / FR input from the first input
terminal 1 to the first volume adjusting means 3a. That is, when the switch SW4 is turned on, the
front channel signal FL / FR inputted from the first input terminal 1 is supplied to the first
volume adjustment means 3a, and when the switch SW4 is turned off, the front channel signal FL
/ FR is outputted. The supply to the first volume adjustment means 3a is blocked. The switch
SW5 is connected between the first input terminal 1 and the second volume adjustment means
3b, and the input path from the first input terminal 1 to the second volume adjustment means 3b
is connected or not connected Switch to In other words, the switch SW5 is for permitting or
blocking the supply of the front channel signal FL / FR input from the first input terminal 1 to
the second volume adjustment means 3b. That is, when the switch SW5 is turned on, the front
channel signal FL / FR inputted from the first input terminal 1 is supplied to the second volume
adjusting means 3b, and when the switch SW5 is turned off, the front channel signal FL / FR is
10-05-2019
9
outputted. The supply to the second volume adjustment means 3b is blocked. The switch SW6 is
connected between the second input terminal 2 and the second volume adjustment means 3b,
and the input path from the second input terminal 2 to the second volume adjustment means 3b
is connected or not connected Switch to In other words, the switch SW6 is for permitting or
blocking supply of the surround channel signal SL / SR input from the second input terminal 2 to
the second volume adjustment means 3b. That is, when the switch SW6 is turned on, the
surround channel signal SL / SR input from the second input terminal 2 is supplied to the second
volume adjustment means 3b, and when the switch SW6 is turned off, the surround channel
signal SL / SR is output. The supply to the second volume adjustment means 3b is blocked.
[0028]
The buffer circuits 10a and 10c are connected between the first input terminal 1 or the second
input terminal 2 and the switch IC 9, respectively. The buffer circuits 10b and 10d are connected
between the switch IC and the first volume control unit 3a or the second volume control unit 3b.
[0029]
Headphones are connected to the headphone output terminal 8. When the headphones are
connected, the headphone output terminal 8 outputs that the headphones and the headphone
output terminal 8 are connected to the control means 5 as a connection signal.
[0030]
The control means 5 controls which speaker and / or headphone the front channel signal FL / FR
or the surround channel signal SL / SR is to be output based on whether the headphone is
connected to the headphone output terminal 8 or not. It is a thing. In other words, based on
whether or not the headphones are connected to the headphone output terminal 8, the switch IC
9 switches the input path from the first input end 1 to the first volume adjustment means 3a, and
the first input end 1 to the second input end. Control switching of the connection state or nonconnection state of the input path to the volume adjustment means 3b and the input path from
the second input terminal 2 to the second volume adjustment means 3b, and the switches SW1 to
SW3 Control the switching of the connection state or non-connection state of the output path
from the second amplification means 4b to the surround speaker, and the output path from the
third amplification means 4c to the headphone. Do. Specifically, based on the presence or
10-05-2019
10
absence of the connection signal from the headphone output terminal 8, the switches SW1 to
SW3 are on / off controlled, and the switches SW4 to SW6 of the switch IC 9 are on / off
controlled. The control means 5 also controls the level adjustment of the audio signal in the first
volume adjustment means 3a and the second volume adjustment means 3b.
[0031]
Next, the operation of the multichannel amplifier having the above configuration will be
described.
[0032]
The control means 5 determines whether a headphone is connected to the headphone output
terminal 8 or not.
Specifically, the control means 5 determines whether or not the headphone is connected to the
headphone output terminal 8 depending on whether or not the connection signal is input from
the headphone output terminal 8, and connects from the headphone output terminal 8. If a signal
is input, it is determined that a headphone is connected to the headphone output terminal 8.
[0033]
FIG. 2 is a diagram showing control of the switches SW1 to SW3 and the switches SW4 to SW6
of the switch IC 9 by the control means 5. When the control means 5 determines that a
headphone is not connected to the headphone output terminal 8, the switch SW1 and the switch
SW4 of the switch IC 9 are turned on and the switch SW5 of the switch IC 9 is turned off. As a
result, the input path from the first input end 1 to the second volume adjustment means 3b is
disconnected, and the front channel signal FL / FR input from the first input end 1 is transmitted
from the buffer circuit 10a, the switch It reaches the first amplification means 4 a via the IC 9,
the first volume adjustment means 3 a and the buffer circuit 10 b, and is outputted to the front
speaker output terminal 6. In addition, with regard to the switch SW2, the switch SW3, and the
switch SW6 of the switch IC 9, when audio is output only from the front speaker, the switch SW6
of the switch IC 9 is turned off or the switch SW2 and the switch SW3 are turned off. When
sound is also output from the surround speakers, the switch SW2 and the switch SW6 of the
switch IC are turned on and the switch SW3 is turned off.
10-05-2019
11
[0034]
When the control means 5 determines that a headphone is connected to the headphone output
terminal 8, the switches SW1 and SW2 and the switches SW4 and SW6 of the switch IC9 are
turned off, and the switch SW3 and the switch SW5 of the switch IC9 are turned on. As a result,
the input path from the first input end 1 to the first volume adjustment means 3a and the input
path from the second input end 2 to the second volume adjustment means 3b are disconnected,
and the first The front channel signal FL / FR inputted from the input end 1 reaches the third
amplification means 4c through the buffer circuit 10a, the switch IC, the buffer circuit 10d and
the second volume adjustment means 3b, and the headphone output terminal 8 Output to
[0035]
As described above, in the multi-channel amplifier according to the present invention, when the
headphones are not connected to the headphone output terminal 8, the buffer circuit from the
first input terminal 1 for outputting the front channel signal FL / FR to the front speaker The
audio signal path from the switch IC 9 to the first volume adjustment means 3a, the buffer circuit
10b and the first amplification means 4a to the front speaker output terminal 6 is not electrically
connected to other audio signal paths The switch IC 9 and the switches SW1 to SW3 are on / off
controlled by the control means 5 so that As a result, the adverse effects that occur when another
audio signal path (especially the audio signal path to the headphone including the third
amplification means 4c) is connected to the audio signal path to the front speaker, ie, the first
amplification means 4a Therefore, it is possible to improve the sound quality of the sound output
from the front speaker without the reduction of the input impedance of the above and the
generation of the inductor component due to the wiring.
[0036]
Furthermore, in the multi-channel amplifier according to the present invention, when the
headphone is connected to the headphone output terminal 8, the buffer circuit 10a is connected
from the first input terminal 1 to output the front channel signal FL / FR to the headphone. The
audio signal path from the switch IC 9, the first volume adjustment means 3b, the buffer circuit
10d and the third amplification means 4c to the headphone output terminal 8 comprises the first
volume adjustment means 3a and the first amplification means 4a. The switch IC 9 and the
switches SW1 to SW3 are on-off controlled by the control means 5 so that the audio signal path
10-05-2019
12
to the front speaker and the input terminal 2 are electrically disconnected. As a result, an adverse
effect occurs when the audio signal path to the front speaker and the input end 2 are connected
to the audio signal path to the headphone, that is, the input impedance of the third amplification
means 4c is reduced, and the inductor component due to the wiring Can suppress the occurrence
of noise, and can improve the sound quality of the sound output from the headphones.
[0037]
In the multi-channel amplifier according to the present invention, the input path from the first
input end 1 to the first volume adjustment means 3a or the second volume adjustment means 3b,
and the second input end 2 to the second one. Since a switch IC is used instead of a relay as
means for switching the input path to the volume adjustment means 3b to the connected state or
the disconnected state, it can be manufactured inexpensively.
[0038]
Also, buffer circuits 10a and 10c are connected between the first input end 1 or the second input
end 2 and the switch IC 9, and the switch IC and the first volume adjustment means 3a or the
second volume adjustment means 3b Distortion of the output of the multi-channel amplifier
caused by the influence of the switch IC 9 can be suppressed by connecting the buffer circuits
10b and 10d between them, and as a result, the sound quality of the sound output from the front
speaker can be further enhanced. The sound output from the surround speaker or the surround
speaker can also be enhanced.
[0039]
In the present embodiment, when the control means 5 determines that a headphone is connected
to the headphone output terminal 8, the switches SW1 and SW2 and the switches SW4 and SW6
of the switch IC9 are turned off, and the switches SW3 and IC9 are Although it has been
described that the switch SW5 is turned on, the supply of the front channel signal to the front
speaker is blocked by the switch SW4 of the switch IC 9, so the switch SW1 may be turned on.
[0040]
In the present embodiment, the switch SW1 is connected between the first amplification means
4a and the front speaker output terminal 6, and the switch SW2 is connected between the second
amplification means 4b and the surround speaker output terminal 7 Although SW3 is connected
between the third amplification means and the headphone output terminal 8, it is not limited
thereto.
10-05-2019
13
For example, the switch SW1 may be switched to the first volume adjustment unit 3a and the
first amplification unit 4a so that the path from the first volume adjustment unit 3a to the first
amplification unit 4a can be switched to the connection state or the disconnection state. Connect
between.
In addition, the switch SW2 is used for the second second amplification means 4b and the
surround speaker output so that the path from the second volume adjustment means 3b to the
first amplification means 4b can be switched to the connection state or the disconnection state.
Connect with terminal 7
The switch SW3 is connected between the third amplification means and the headphone output
terminal 8 so that the path from the second volume adjustment means 3b to the third
amplification means 4c can be switched to the connection state or the disconnection state.
Connect to The switch SW2 and the switch SW3 are also connected to the second volume
adjustment unit 3b so that the second amplification unit 4b and the third amplification unit are
connected in parallel to the second volume adjustment unit 3b. Connected in parallel. The on /
off control of the switches SW1 to SW3 in this case is the same as the on / off control in the
above-described embodiment.
[0041]
As mentioned above, although embodiment of this invention was described, embodiment
mentioned above is only an illustration for implementing this invention. Therefore, the present
invention is not limited to the embodiment described above, and the embodiment described
above can be appropriately modified and implemented without departing from the scope of the
invention.
[0042]
The multi-channel amplifier of the present invention can be used in electronic devices for all
applications, but can be suitably used in audio equipment and the like.
[0043]
10-05-2019
14
FIG. 1 is a circuit diagram illustrating a multi-channel amplifier according to a preferred
embodiment of the present invention.
FIG. 6 is a diagram showing control of a switch by control means in a preferred embodiment of
the present invention. It is a circuit diagram explaining the conventional multi-channel amplifier.
Explanation of sign
[0044]
DESCRIPTION OF SYMBOLS 1 1st input terminal 2 2nd input terminal 3a 1st volume adjustment
means 3b 2nd volume adjustment means 4a 1st amplification means 4b 2nd amplification means
4c 3rd amplification means 5 control means 6 front speaker Output terminal 7 Surround speaker
output terminal 8 Headphone output terminal 9 Switch IC 10a to 10d Buffer circuit SW1 to SW6
Switch OP1, OP2 Operational amplifier VR1 to VR4 Variable resistor FL / FR Front channel signal
SL / SR Surround channel signal
10-05-2019
15

Download Report