DE1562062A1 - Adjustable amplifier for acoustic frequencies, preferably for use in electronic musical instruments - Google Patents

Description

Company FARi ¹ ISA S.ρ.Α., Aspio Terme (Camerano) Ancona

( Italy )

Adjustable amplifier for acoustic frequencies, preferably for use in electronic musical instruments

Me Irfiafeig ^ ßii ^ lfft einsa segeifcas-ea Terstä ^ ker for acoustic Fi'ecyaeases.s'iFos'siigsweis © sui ⁵ YesfaenfliÄig in

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However, this problem arises particularly with electronic musical instruments. Here we * by arbitrarily adding or subtracting frequencies, the sound spectrum changes what does ßich the desired acoustic effects result. For example, the timbres of different Instruments can be made in a tile manner.

The previously known amplifiers in electronic musical instruments could only be inadequately adapted to the frequencies to be amplified. In addition, with amplifiers known so far, one is not in a position to be controlled from the outside. Affect the proportion of the individual frequency bands on the output spectrum in a simple manner.

With the invention we ^ remedied this, dais in the working group of the amplifier element in sections ve r ε er.

Filter groups subdivided into equal frequencies. but uras cn old he can be switched on in sections, and each filter group can be regulated via a regulating wiflerstc.:,.^ b3zügli:;

Pas amplifier eleaant can use a ™ rnnr: 2 : .. tor, »In Ί? Β9ύ & * '* 4> ^ i & x, an electron tube or an ' ir ^ .loge-u Halt": · ; :: απ, - 1 will be «Me filter groups or filters! ¹ .-.-. ■■: ei ν ■: ε η throw out in an expedient manner

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Inductivities, capacitances or combinations of these Switching elements built up. In particular, there are Re-Gonans circles tailored to the respective frequencies at.

Confused by the measures according to the invention? achieved that flurch the operation of the switch of the amplifier can throw discontinuously angepai3t to be amplified or to the unterdrükk end en frequencies while riie the filter groups regulating ohm variable resistors ¹ see a further, continuous adjustment of the amplifier allow.

Further features and advantages of the invention are apparent the exemplary embodiments described below with reference to drawings. Here shows:

Fig. 1 shows the circuit of an amplifier with in Subsections of divided piIter groups, and

Pig. 2 shows the circuit of an amplifier in which the filter groups are not further subdivided.

In FIG. 1, the filter groups are designated by the numbers 1, 2, 3, 4, "and 5. The individual groups are in Divided into sections. Each section has a capacitance and associated ohmic resistances or inductances so that each section has its own tuning frequency comes to.

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The filter groups 1 and 2 are connected on one side to the respective terminals of Umachaltern, while on the other side they are connected to ground via ohmic resistors and inductors 6 and 7. The sections are to be thought of as being built up only from capacitances and ohms ^{1 see resistors.} This results in a resonance frequency for each section through the series connection of capacitance and inductance. This works in the amplifier network by switching on the switch from terminal 14 or 20 to one of terminals 15-19 or 21-24. It is the Pig. 1 shows that when the first switch is set to terminal 14, filter group 1 is completely switched off from the active power supply, while when the switch of group 2 is set to terminal 20, the full group is connected.

When the pilter groups are connected to the network, the respective effectiveness can also be regulated via the control resistors 9 and 10.

It is easy to see that filter groups 1 and 2 are connected in parallel. Still are, however, too the piiter groups 3, 4 and 5 connected in parallel. she correspond in their arrangement in the overall network to the arrangement of filter groups 1 and 2. However, the groups are in turn developed differently than the groups first described. So are the two groups 3 and connected in parallel to each other, and lie together with

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one side on the wiper of a common variable resistor 35. To switch on the desired frequency ranges, a changeover switch that acts jointly on the sections of both groups is provided. The two switching contacts of the changeover switch are preferably mechanically rigidly coupled and can be switched from the empty terminals 25 or 25 'to the terminals 26-29 or 26'-29 ^f . The two filter groups are then each connected to ground via ohmic resistors and inductances connected in series.

Another possible embodiment of a filter group is shown with the filter group 5. No inductance is assigned to this filter group, but only an ^{ohmic 1} shear resistor 37. The sections are only formed from capacitive partial circles. The switching contact of a changeover switch acts on terminals 30 - 34 »and the influence of this filter group when the amplifier is running is controlled via the level resistor 36.

For the sake of completeness, it should also be noted that the combination of filter groups and Hegel resistors described above is in the working circuit of transistor 13, ä, h * between collector c and. Emitter e of the transistor 13 connected in the emitter circuit is coupled. Capacitors are expediently used for coupling. It can also be seen that a resistor - 11 to the collector and a resistor 12 to the emitter

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assigned.

FIG. 2 shows one of the circuits shown in FIG. 1 basically analog circuit shown. However, there are none in sections with different tuning frequencies divided filter groups are provided, but built up from capacitance and inductance Series resonance circuits starting with the digits 38-4-1 are designated. As mentioned, the arrangement of these resonance circuits in the amplifier network is basically the same that of the parent groups. It can be seen that one side of the resonance circles with the wiper of the Potentiometer 42 - 45 is connected, so that here a discontinuous adjustment of the response curve of the Amplifier is not possible, but "diglich the continuous adjustment effected by the potentiometer.

The amplifier element in the form of a transistor is indicated at 46 in Pig * 2. 8 denotes the ground contact, as is also the case in Mg. 1.

In the context of the invention, it is also possible to use the capacities replace the sections of the groups of parents (Fig. 1) with inductors, and then replace the groups of parents to assign capacities instead of inductances.

Finally, it should be noted that through the Invention not only in a surprising and simple way

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Low frequency amplifiers especially in electronic Musical instruments the frequencies to be amplified or suppressed in a purely technical way Yfeise can advertise adapted, but that through the circuit according to the invention in electronic musical instruments extremely surprising, aesthetically highly effective new sounds can also be generated.

- patent claims -

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Claims (1)

Claims 1. Adjustable amplifier for acoustic frequencies, preferably for use in. Electronic musical instruments, characterized in that in the working group (e, c) of the amplifier element (13) divided into sections of different frequencies filter groups (1,2,3,4,5) Changeover switches (H - 19, 20 - ZA ₉ 25 - 291 25 '- 29', 30 - 34) are arranged so that they can be switched on in sections, and each filter group can be regulated with respect to its filter effect via a control resistor (9, 10, 35, 36). 2. Amplifier according to claim 1, characterized in that the amplifier element (13) is a transistor. 3. Amplifier according to claim 1, characterized in that the electrical amplifier element (13) e, ine Electron tube is. 4. Amplifier according to one of claims 1-3, characterized in that the working electrodes (e, c) of the amplifier element (13), preferably via capacitors, ^{see a parallel connection of adjustable Ohm f} resistors (9,10,35,36; 42, 43,44,45) is coupled, and the filters (1,2,3,4,5} 38,39,40,41) are arranged between the wiper terminals and ground parallel to the cathode or emitter resistor (12). 0098 0 9/0663 BATH ORIGINAL 5. amplifier NaOH any one of claims 1-4 _f characterized in that the filter groups (1.2, 2 »4) switchable from parallel capacitor sections and inductance serielgeschiteten to tile a shakes address (6,7). 6. Amplifier according to one of claims 1 - 5 t flarturch characterized in that a pilter group (5) from parallel Switchable condenser sections without additional inductance exist. ' 7 · Amplifier according to one of the claims 1-6, flat marked, partially or flowed toggle switch mechanically coupled to each other 8. Amplifier according to claim 5 or 6, marked flaflurch, Sat for the capacitors (due to influences and the inductances are replaced by capacitors February 21, 1968/431 0 09809/0683