CZ307875B6 - Equipment for remotely controlling electronic devices potentiometers, especially analogue music amplifiers - Google Patents

Abstract

The device for remotely controlling potentiometers (2) of electronic devices, in particular analogue music amplifiers (3), consists of at least one external actuator (4) of the potentiometer (2) of the amplifier (3), consisting of a removable body (5) attached by a clamp to the outer surface amplifiers (3), at least one rotatable head (6) that can be mounted on a potentiometer (2) connected to the housing (5), a servo drive (8) for rotating the rotating head (6), and a control unit (19) to control the rotation of the servo drive (8) and for storing the set positions of the servo drive (8), the device also consists of at least one foot control means (20, 21, 22, 23) wired or wirelessly connected to the control unit (19) for switching the set servo drive positions (8) in the control unit (19).

Description

Technical field

The invention relates to electronics, in particular to devices for the remote control of potentiometers of electronic devices, in particular analogue music amplifiers of a higher quality class.

BACKGROUND OF THE INVENTION

The current mass production of music amplifiers is based on SMD components, printed circuit board minimization and digitization, including multiple use of AD / DA converters to minimize costs. All of this has a demonstrably negative effect on the sound.

Digital amplifiers with remote control are well known. This segment also includes simulation / modeling devices that try to replace analogue amplifiers with digital technology. These are instruments based on a combination of synthesis and standard convolution, or more advanced technology experimenting with dynamic convolution analysis. Said digital amplifiers are generally perceived by musicians as inferior and incomparable to the above-described tube amplifiers. Because digital amplifiers are light and small, they are used as intermediate solutions for greater mobility, but at the expense of sound quality. To achieve good sound, their popularity is far from reaching tube amplifiers, which are privileged in terms of truly quality amplification.

The true quality amplifiers that musicians love to use are largely based on the design principles defined in the 1950s and 1960s to achieve the highest sound quality. They are equipped with specific components such as coil capacitors, ceramic resistors, so-called NOS components (New Old Stock) are often used. The instruments are constructed using traditional methods such as solder loops, using cables and cables instead of conductive printed circuit boards, using manually wound transformers, etc. Such amplifiers show a fundamental qualitative difference from the current mass production. From the acoustics point of view, qualitative specifics include a higher proportion of even aliquots, specific hysteresis in amplification given by the transition characteristics of the tubes, influence of conversion transformers, dynamics and color of sound. For all the above reasons, the idea of any interference with the device is totally unacceptable to the vast majority of owners of such high-quality music amplifiers.

Remote control solutions for music analogue amplifier or lamp or transistor combo are also known, and combo means amplifier with loudspeaker in a single cabinet. For purposes of the following description, the common term amplifier will be used. The remote control controls a selected controllable parameter such as volume, distortion, bass, treble, etc. The standard procedure for installing a remote control on such an electronic device is to remove the designated control and replace it with a motorized potentiometer while installing the control electronics in the amplifier cabinet. All of this, however, is virtually impossible to do with quality music amplifiers without losing the qualitative sound parameters that musicians use it for. Furthermore, two or three channel amplifier models of lamp and transistor amplifiers are known. However, in these cases a compromise in the form of joint corrections is very common; the same equalizer for these channels. This in itself significantly reduces the possibilities of sound flexibility and without additional effects, the possibilities of multichannel amplifiers are as limited as those of single-channel amplifiers.

With high quality analog amplifiers, the guitar sounds best in the simplest possible connection: guitar, cable, amplifier. This sound is harmoniously colored and very dynamic. Different techniques of the game will be marked on it: fingers, plectrum, flasks, pulling

The characteristics of the instrument are transferred to the overall sound; it will show used wood of the fingerboard, body and neck, string height and strength, used sensors and other factors. A major plus is the overall feeling of playing, when the musician perceives very well the response of the resulting tone to his playing technique.

The obvious disadvantage is the ability to have only one set sound. This is a big limitation because even the simplest styles require at least three basic sounds: pure, distorted and solo. For our purposes, it is important to realize that the transition between the three "pure-distorted solo" sounds can be achieved by adjusting the volume potentiometers appropriately, possibly together with Gain. Most musicians use an even greater number of sounds than the three basic ones. This is because of greater color and scalability when playing music. The following is a list of standard options for making multiple sounds available:

The musician sets a strongly distorted sound. The sound is then changed by the volume potentiometer on the guitar. The disadvantage is that turning the volume potentiometers on the guitar will change the color of the sound, because the capacitor and resistive load are in the way. This change is significant, not suitable for a large number of musicians. The main disadvantage is the impossibility to change the sound every time as well - we are never able to turn the potentiometer the same way as in the previous moment, we always have a slightly different sound (except for the extreme position). This procedure is also unsatisfactory for obtaining a ringing clear sound, as there is a capacitor in the path that removes the heights.

The musician will include effect devices in the signal path: either between the guitar and the amplifier, or into the effect loop. The disadvantage is that the sound is not as good as the basic guitar-cable-amplifier connection, the signal degradation is audible. This procedure is most common, but at the expense of sound quality. Such solutions are described, for example, in US 7678985 (B2) and US 6881891 (B1).

The musician has multiple amplifiers available, switching the signal path from the guitar to the selected amplifier. The disadvantage is that there is a signal switch in the signal path. The cost of purchasing several amplifiers is very high, and it is also a solution that has considerable space requirements.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an amplifier potentiometer remote control that allows different sounds to be set and switched without the need for external effects or multiple amplifiers, but the guitar is connected directly to the amplifier via cable, without interfering with its design sound. Such a solution would allow extending the capabilities of music analogue amplifiers and lamp and transistor combos to include remote control and sound change without compromising quality.

SUMMARY OF THE INVENTION

The object is solved by a device for remote control of potentiometers of electronic devices, especially analogue music amplifiers according to the present invention. The device consists of at least one external amplifier potentiometer control that has foot control and rotates the amplifier potentiometer, e.g., volume or distortion, so that the musician can change the volume or sound color during play during play. The external actuator includes a body detachably mounted by means of clamping means to the outer surface of the amplifier, at least one rotatable head adapted to be mounted on a potentiometer attached to the housing, an actuator for rotating the rotatable head, and a control unit for controlling the actuator rotation and storing the actuator positions from at least one foot control means connected wired or wirelessly to the control unit for switching the set positions of the actuator stored in the control unit.

The device is designed in the form of external non-invasive device. The basic principle is based

-2GB 307875 B6 to mechanically attach the external controller to the amplifier and transfer torque from the motorized shaft of the actuator via the rotary head to the amplifier potentiometer. It does not have to be just a music amplifier, the solution can be used for various electronic devices equipped with potentiometers, which require their remote foot control. With regard to the above mentioned specific requirements of high-quality audio devices, the presented solution also meets the conditions of non-intervention installation into the device and attachment to the device without mechanical damage.

The clamping means may be of various design known to the person skilled in the art, such as Velcro, gluing, screws and other fasteners and the like. For simplicity and non-interference with the amplifier structure, it is preferred that the clamping means for detachably clamping the body to the amplifier is at least one spring element provided at the end with a hook that grabs the edge of the amplifier wall. Removal and deployment is fast and strong enough.

Also, the connection of the rotary head to the housing and the location of the actuator for rotating the rotary head can have a variety of designs. In a preferred embodiment of the invention, the pivoting head is attached to the body by a support arm which forms an L-shape with the body, the body being mounted on a side of the amplifier other than the amplifier potentiometer, the support arm extending on that side of the amplifier on an amplifier potentiometer is provided, and a rotating head with an actuator is mounted on the support arm.

Since the distances of the potentiometers from the edge of the amplifier wall are different for different amplifiers, it is advantageous that the rotary head with the actuator is mounted on the support arm with the possibility of sliding its position on the support arm.

It is also advantageous if the support arm is split and is provided with a hinge for tilting the part of the support arm supporting the rotary head with the actuator. If the musician wants to operate the potentiometer manually, he or she does not have to remove the entire external controller, it is enough to open the swinging arm, and the controller remains attached to the amplifier.

The rotary head is preferably adapted to be mounted on an amplifier potentiometer such that an internal shaped recess is formed therein, the shape of which corresponds to the external shape of the amplifier potentiometers. Thus, the rotary head is simply mounted on the potentiometer, tightly encircling it, and since the potentiometer is usually provided with protrusions, the knob has a groove corresponding to these protrusions or the force is transmitted by adhesion. Alternatively, the rotating head could be clamped to the potentiometers in other ways such as clamps, magnets, Velcro, and the like.

In one preferred embodiment of the invention, the at least two external potentiometer actuators are separately mounted and movable on a common prismatic bar provided with a clamping means for clamping to the amplifier surface formed by a resilient element provided at the end of the hook. This makes it possible to place several external controls on the prism strip in one clamping, the position of which is adjusted to the position and pitch of the amplifier potentiometers by sliding on the bar.

In another preferred embodiment of the invention, the at least two external actuators are integrated into an integrated body to which an integrated support arm is mounted to which the pull-out can be adjusted, on which a support bar carrying at least two rotating heads with actuators is fixed. This embodiment has fixed pitches of the swivel heads and is designed for a particular type of amplifier where the musician buys two or three or more swivel heads with servo drives and puts them on the slots in the support rail to positions corresponding to the potentiometers he wants to control. Preferably, the integrated body is supported on a support foot, and provided with a clamping means for clamping to the amplifier surface formed by a resilient element provided with a hook at the end.

The control unit comprises a processor, a memory for storing actuator position setpoints, and software means for controlling the actuator storing and controlling the actuator movement between the actuator setpoints according to an output signal from at least one foot control.

The control unit includes an output to the actuator, an input from the actuator, and control means for adjusting and storing the actuator position setpoints.

In a preferred embodiment of the invention, the control unit is housed in a body where it is protected, but could in principle be stored anywhere else outside the body, eg in a foot control means. In the simplest version, in addition to the control unit, mechanical-electric control means for setting and storing the set values of the actuator position are stored in the housing. These means comprise an adjusting potentiometer for manually adjusting the position of the actuator, a button for selecting the first set position of the actuator, a button for selecting the second set position of the actuator, and a button for storing the set values. Turning the adjusting potentiometer rotates the actuator and rotates the amplifier potentiometer through the swivel head to the position the musician wants to store. Saving is performed by simultaneously pressing the button to select the first set position of the actuator or the button to select the second set position of the actuator and the button for storing the set values into the memory.

In another preferred embodiment of the invention, the control unit is connected via an MIDI protocol or USB port to an external computer, tablet or wirelessly or via a USB port to a smartphone which includes software control means for adjusting and storing actuator position settings in the control unit. in her memory.

The foot control means is preferably a two-position switch or a multi-position switch or a continuous pedal or MIDI-type controller.

A major advantage of the present device is that it allows use in high-end musical instruments where the classical retrofit of the remote control with intervention into the device cannot be performed. Other than manual operation is not possible here. On the other hand, the possibility of remote control significantly expands their sound palette. This is especially useful when playing live: changing the volume, adjusting the amount of distortion and possibly changing the equalization bands, etc.

Further advantages of the present device are based on the above principles that have been taken into account in the design. The installation requires neither mechanical nor electronic intervention in the amplifier. Fixing to the amplifier is without mechanical damage, is easy and fast. The design was tested to accommodate as many types of amplifiers as possible. It is easy to transport, has a compact design, does not impose any specific knowledge requirements. Another advantage is the mobility of the user, who does not have to be fixed to the space within the range of the device during the period of use. Another benefit is the possibility of programmatic adjustment of individual positions in time. The solution will enable accurate positioning of the control element, which cannot be reached by human hand. The device eliminates the need for additional devices (effect devices: floor or rack effects). This consequently results in a simplification of the signal chain, where it is not necessary to connect devices that cause some signal degradation and additional costs between the instrument and the amplifier. It is therefore acceptable for the highest quality class.

Clarification of drawings

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 a front perspective view of an amplifier with potentiometers on the front plate, with one external control mounted on a volume potentiometer, and a foot pedal type continuous pedal, with a guitar connected directly to the amplifier via a cable; on the top plate, with two

-4GB 307875 B6 with external controls mounted on volume and distortion potentiometers and with MIDI foot control, with guitar connected directly to the amplifier via cable, Fig. 3 rear perspective view of amplifier according to Fig. 1, showing clamping means for clamping external controls Fig. 4 front perspective view of an external actuator mounted on a prismatic bar, Fig. 5 front perspective view of an external actuator mounted on a support foot, Fig. 6 front perspective view of three external actuators mounted on a common prismatic Fig. 7 is a front perspective view of five external controls integrated into the integrated body mounted on the amplifier with potentiometers on the front; Fig. 8: conical potentiometer with knurling and protrusion; recess m for the potentiometer according to Fig. 8, Fig. 9 conical potentiometer with knurling, Fig. 9 'rotary head with recess for potentiometer according to Fig. 9, Fig. 10 conical potentiometer without knurling, Fig. 10' rotary head with recess for potentiometer according to Fig. 10, Fig. 11 a wedge-shaped potentiometer, Fig. 11 'a rotating head with a recess for the potentiometer according to Fig. 11, Fig. 12 a block diagram of the device according to the invention

DETAILED DESCRIPTION OF THE INVENTION

The first example of FIG. 1 shows a front perspective view of an amplifier 3 with potentiometers 2 on the front plate, with a single external actuator 4 mounted on a volume potentiometer 2, and with a foot pedal 22, with a guitar 1 connected directly to the cable 17 The continuous pedal 22 is shown by way of example only in FIG. 1, the foot control means may also be a two-position switch 20 or a multi-position switch 21 or a MIDI-type 23 controller. 4. The connection can also be made as wireless as described below. The body 5 is mounted on the upper plate of the amplifier 3 and is fastened to the rear edge of the upper plate of the amplifier 3 by means of a resilient element 9 with a hook 10. The resilient element 9 is formed by a rubber cable. It is also possible to attach it to the control panel covers, the side edges, or the main handle for carrying the amplifier 3. The housing 5 houses a control unit 19 with a processor 28 which includes a memory 29 for storing the actuator 8 position settings and software 30 control of storing the set values and controlling the movement of the actuator 8 between the set values according to the output signal from the foot control means 20, 21, 22, 23, according to the diagram in Fig. 12. which comprise an adjusting potentiometer 24 for manually adjusting the position of the actuator 8, a button 26 for selecting the first set position of the actuator 8, a button 27 for selecting the second set position of the actuator 8, and a button 25 for storing the set values. for two-position ex If the multi-position switch 21 was used, the body 5 would have additional buttons (not shown) for selecting the third to the nth set position of the actuator 8. To the body 5 there is a rectangularly mounted support arm 7 which extends on the front plate of the amplifier 3 The volume arm potentiometer 2, which is not visible in FIG. 1, is mounted in the rotatable head 6. The support arm 7 has an oval opening 35 through which the fastening bolt passes from the housing 5 and is fastened to the bolt by a wing nut 34. This fastening enables positioning The support arm 7 so that the end of the support arm 7 reaches the potentiometer 2. The attachment of the support arm 7 to the body 5 can also be carried out in a number of other ways known to the person skilled in the art. At the end of the support arm 7 there is an actuator 8 which is connected to the rotary head 6 by a fixed connection or flexibly by means of a cable not shown. The rotatable head 6 is adapted to be mounted on the potentiometer 2 of the amplifier 3 so as to form an internal shaped recess 12, the shape of which complements the outer shape of the potentiometer 2 of the amplifier 3. Examples

The shape options are shown in Figures 8 to 11 '. The actuator 8 is connected to the control unit 19 in the housing 5 by an output 32 from the control unit 19 to the actuator 8 and an input 33 to the control unit 19 from the actuator 8. These cables are not visible in Fig. 1 because they are housed in the support arm 7 but shown in the diagram of FIG. 12.

The device according to FIG. 1 works by placing the body 5 on the amplifier 3 and the rotating head 6 on the volume potentiometer 2. By turning the adjusting potentiometer 24, the actuator 8 is actuated, which rotates the potentiometer 2 of the amplifier 3 over the rotating head 6 as if the musician had turned it manually. The position corresponding to the lower volume is selected, and by simultaneously pressing the button 26 to select the first set position of the actuator 8 and the button 25 for storing the set value, this position is stored by means of software 30 into the memory 29 of the processor 28 of the control unit 19. the position corresponding to the higher volume, and by simultaneously pressing the button 27 to select the second set position of the actuator 8 and the button 25 for storing the set value, this position is stored by means of software 30 into the memory 29 of the processor 28 of the control unit 19. During the game, the musician switches between the set positions of the actuator 8 and thus between the lower volume and the higher volume by means of the foot control 20, 21, 22, 23 with his hands free and still working. IVA natural sound quality amplifier 3 Foot control means 20, 21, 22, 23 is generally passive and does not require power, but it may be supplied via an external controller 4, or may have the external controller 4 supplies its own, e.g. battery.

The second example of Figures 2 and 3 shows a front perspective view of an amplifier 3 with potentiometers 2 on the top plate, with two external controls 4 mounted on potentiometers 2 of volume and distortion, and with a foot control of the multi-position switch 21. via the connection cable 17 directly to the guitar input of the amplifier 3. The multi-position switch 21 is connected by the control cable 18 to the bodies 5 of both external actuators 4, the construction of which is the same as in the first exemplary embodiment. The bodies 5 are supported on the support feet 16 on the rear plate of the amplifier 3 and fastened by the resilient elements 9 with the hooks 10 to its rear edge. The support arms 7 extend to the potentiometers 2 on the top plate of the amplifier 3. The design of the external actuators 4 is the same as in example 1, each of which can store at least two set positions of the actuator 8, which are then toggled with the foot switches on the multi-position switch 21. and the power supply is solved as in the first embodiment. This example is suitable for simultaneous operation of two potentiometers 2, eg volume and distortion. The musician can store the sounds given by the combinations of set positions of each potentiometer

2. The body 5 is in the form of a narrow box, approximately 2 cm wide. The normal pitch between potentiometers 2 of amplifiers 3 is 3 to 4 cm for easy access for control and plenty of room. The high-quality analog amplifiers 3 are large because there are space-intensive parts such as transformers, lamps, coil capacitors, etc. inside the chassis. Thus, one external amplifier 3 can be placed side by side without any problems. 5 is a perspective view of the hinge 11 for tilting the end portion of the support arm 7 with the actuator 8 and the rotating head 6.

The third example of Figures 4 and 6 illustrates an embodiment comprising three external actuators 4 whose construction is the same as in the first and second examples, but which are mounted slidably on a common prismatic bar 13 on the amplifier 3 with potentiometers 2 on the front. The support foot 16 of the body 5 fits into one of the two prismatic grooves 15 on the prismatic bar 13. By moving the bodies 5 along the prismatic bar 13, the position of the rotary head 6 corresponding to a particular potentiometer 2 is found, eg volume, distortion and bass or treble. To mount the external actuators 4, the prism strip 13 is placed on the amplifier 3 and fastened by the elastic element 9 with the hook 10 at the edge of the upper plate of the amplifier 3. with the edge of the amplifier 3 so that the rotating heads engage the potentiometers 2. Saving, switching and power supply are solved as in the first exemplary embodiment. The musician can store sounds from combinations of set positions

-6E 307875 B6 to control the switching of each potentiometer 2 using the selected foot control means 20, 21, 22, 23.

The fourth example of Fig. 7 is a front perspective view of five external actuators 4 integrated into the integrated body 5 'mounted on an amplifier 3 with potentiometers 2 on the front plate. The external actuators 4 do not have separate bodies 5, but are located in an integrated body 5 ', to which an integrated support arm T is mounted to which the support bar 14 is supported, on which the support bar 14 carrying five rotating heads 6 with servo drives 8 is mounted. The musician chooses which cutout 36 he wants to fit and which potentiometer 2 he wants to control by means of the selected foot control means 20, 21, 22, 23. The integrated body 5 / is mounted on the support 16, and provided with a clamping means for clamping to the surface of the amplifier 3 formed by a resilient element 9 provided with a hook 10 at the end. Saving, switching and powering are the same as in the first embodiment. It is a compact solution for using multiple external controllers 4 at the same time to set up a rich combination of sounds. For each of the most common types of amplifiers 3, such as Fender, Marshall, Bogner, the carrier strips 14 are adapted in shape and pitch, which allows the entire assembly to be quickly mounted on the amplifier 3 and removed.

The switching of the set positions of the actuator 8 is controlled by the selected foot control means 20, 21, 22, 23. The two-position switch 20 allows switching between two sounds, which is the simplest solution. It does not require any sophisticated extra devices. In conjunction with the multi-channel amplifier 3, it allows to fully cover the requirements for basic types of sounds. The multi-position switch 21 is in the form of a bar on which several foot switches are located. Pressing them will switch the external controller 4 to the programmed position for the respective set position of the actuator 8. Three, five or even more foot switches are available in multiple rows. The foot continuous pedal 22 allows the position of potentiometers 2 to be changed continuously remotely. The MIDI controller 23 transmits data whose structure and frame are generally defined by the standard. This MIDI protocol is standard in the field of musical instruments. It allows to connect any MIDI foot pedal (eg Rocktron, Voodoo Lab) via standard MIDI cable 31 to the control unit 19. The MIDI IN connector or MIDI Out resp. MIDI Thru for concatenation of other MIDI devices.

The method of transmitting the signal between the foot control means 20, 21, 22, 23 and the actual external control 4 can be made in a wire by means of a control cable 18, as shown in the accompanying drawings. Depending on the type of foot control means 20, 21, 22, 23, a two-wire or multi-wire control cable 18 will be used. A serial interface with USB connectors can be used. An unconnected wireless connection, such as Bluetooth, Wi-Fi, etc., can also be used.

The method of programming and adjusting the positions of the actuator 8 can be solved manually, as shown in the accompanying drawings and described above, i.e. the actuating means for adjusting and storing the actuator 8 position setpoints are arranged in the housing 5 and comprise an adjusting potentiometer 24 for manual positioning of actuator 8, button 26 for selecting the first set position of actuator 8, button 27 for selecting the second set position of actuator 8, and button 25 for storing set values in memory 29.

In other non-illustrated embodiments, the actuating means for adjusting and storing the setpoint values of the actuator 8 may be remote. The control unit 19 may be connected wirelessly or via a USB port (not shown) to an external computer or tablet not shown, which includes software control means for adjusting and storing actuator 8 position values. Or, the control unit 19 may be wirelessly connected to a smartphone that contains control means for setting and storing the set values of the actuator 8 position

Store the set positions in the memory, transfer them between the foot control means 20, 21, 22, 23. perform manual regulation, etc.

Through the application located in the smartphone, the user will move the finger on the display to change the position of the actuator 8. After reaching the desired position it will save it in the smartphone memory. The set positions will be automatically transferred to the control unit 19. This means that you will not need to use your smartphone during music production. Thus, the switching of stored sounds will continue to take place via the foot control means 20, 21, 22, 23 as described above. The manner of storing the positions in the memory 29 will change. Advantageously, it will thus be possible to change the stored settings in the memory 29 remotely, without having to stand directly at the amplifier 3. Furthermore, it will be possible to store the position settings of several servo drives 8 at once. The recall of the stored memory 29 thus causes the simultaneous adjustment of several actuators 8 at the same time, which is suitable for the embodiment according to the third and fourth examples. This will allow a more complex sound change at one time.

Power to the external controller 4 is provided by a battery (not shown) housed in the housing 5, eg 9V or an external adapter not shown, or via a powered foot control means 20, 21, 22, 23.

Industrial applicability

The device according to the invention can be used for remote control of potentiometers of electronic devices, especially analogue music amplifiers of higher quality class.

PATENT CLAIMS

Claims (14)

A device for remote control of potentiometers (2) of electronic devices, in particular analogue music amplifiers (3), characterized in that it comprises at least one external controller (4) of potentiometers (2) of an amplifier (3) comprising a removable body (5) fastened by means of clamping means to the outer surface of the amplifier (3), at least one rotatable head (6) adapted to be mounted on a potentiometer (2) connected to the housing (5), an actuator (8) for rotating the rotatable head (6), (19) for controlling the rotation of the actuator (8) and for storing the set positions of the actuator (8), the apparatus further comprising at least one foot control means (20,21,22,23) connected wired or wireless to the control unit (19) for switching the set positions of the actuator (8) stored in the control unit (19). Device according to claim 1, characterized in that the clamping means for detachably clamping the body (5) to the amplifier (3) comprises at least one spring element (9) provided at the end with a hook (10). Device according to claim 1 or 2, characterized in that the at least one rotatable head (6) is connected to the body (5) by means of a support arm (7) which forms an "L" shape with the body (5), (5) is mounted on a side of the amplifier (3) other than the potentiometer (2) of the amplifier (3), the support arm (7) extending on that side of the amplifier (3) on which the amplifier potentiometer (2) is arranged ( 3), and a rotating head (6) with an actuator (8) is mounted on the support arm (7). Device according to claim 3, characterized in that the rotary head (6) with the actuator (8) is mounted on the support arm (7) with the possibility of sliding its position on the support arm (7). - 8 GB 307875 B6 Device according to claim 3 or 4, characterized in that the support arm (7) is split and is provided with a hinge (11) for tilting the part of the support arm (7) supporting the rotary head (6) with the actuator (8). Device according to one of Claims 1 to 5, characterized in that the rotating head (6) is adapted to be mounted on the potentiometer (2) of the amplifier (3) in such a way that an internal shaped recess (12) is formed therein corresponds to the external shape of the potentiometer (2) of the amplifier (3). Device according to one of Claims 3 to 6, characterized in that at least two external actuators (4) of the potentiometer (2) are mounted separately with the possibility of their sliding on a common prismatic bar (13) which is provided with clamping means for clamping. to the surface of the amplifier (3) formed by a resilient element (9) provided at the end with a hook (10). Device according to one of Claims 3 to 6, characterized in that at least two external actuators (4) are integrated into an integrated body (5 ') to which the integrated support arm (7') is attached to a support rail (14) carrying at least two rotatable heads (6) with actuators (8) is fastened. Device according to claim 8, characterized in that the integrated body (5 ') is mounted on a support foot (16) and provided with a clamping means for clamping to the surface of the amplifier (3) formed by a resilient element (9) provided with a hook at the end (10). Device according to one of Claims 1 to 9, characterized in that the control unit (19) comprises a processor (28), a memory (29) for storing the setpoints of the actuator (8) and a software means (30) for controlling the setpoints. and controlling the movement of the actuator (8) between the set values according to the output signal from at least one foot control means (20,21,22,23) with which the control unit (19) is connected by a control cable (18) or a MIDI cable (31) or wirelessly, the control unit (19) further comprising an output (32) to the actuator, an input (33) from the actuator (8), and control means for adjusting and storing the actuator position (8). Device according to claim 10, characterized in that the control unit (19) is housed in the housing (5) and the control means for adjusting and storing the set values of the actuator position (8) are also arranged in the housing (5) potentiometer (24) for manual positioning of actuator (8), button (26) for selecting the first set position of actuator (8), button (27) for selecting the second set position of actuator (8), and button (25) for storing set values to memory (29). Device according to claim 10, characterized in that the control unit (19) is connected via an MIDI protocol or a USB port to an external computer or tablet, which comprises software control means for adjusting and storing the position values of the actuator (8). Device according to claim 10, characterized in that the control unit (19) is connected wirelessly or via a USB port to a smartphone which comprises software control means for adjusting and storing the position values of the actuator (8). Device according to any one of claims 1 to 13, characterized in that the foot control means is comprised of a two-position switch (20) or a multi-position switch (21) or a continuous pedal (22) or a MIDI-type controller (23).