JPS596515Y2 - Amplifier switching device for 8-track cassette tape recorder - Google Patents

Description

[Detailed explanation of the idea] This idea has 8 tracks. The present invention relates to an amplifier switching device in a cassette tape recorder.

8 tracks. When you listen to a music tape on a tape recorder that also serves as a cassette, you will feel a difference in sound pressure level, that is, a difference in playback output between the 8-track and cassette tapes.

This is due to the difference in the recording level of commercially available music tapes, with the cassette tape being about 3 to 5 dB lower on average than the 8-track tape.

Therefore, it is necessary to correct the gain using an amplifier.

This is because it is more economical to use an amplifier in common in an apparatus in which an 8-track tape and a cassette tape are used in the same machine.

However, since the heads are different between the 8-track and the cassette, and the tape widths are also different, it is preferable to adjust the level by switching the increase degree of the amplifier.

Is this the case when searching for 8-track cartridges or cassettes? The switch is automatically operated by utilizing the difference in the insertion position, etc., and the above-mentioned amplifier is switched.

FIG. 1 is a circuit diagram of one embodiment of the present device, in which 1 is an 8-track head, and 2 is a cassette head, each of which is connected to a fixed contact S15S1 of a selector switch S1.

Furthermore, the movable portion S13 is connected to the base of the amplifier transistor Tr1.

On the other hand, the emitter of transistor Tr1 is connected to resistors R1 and R2.
grounded through the parallel connection of

Further, in the present invention, a switch S2 which operates in conjunction with the changeover switch S1 is connected in series with the resistor R2, and in the case of the cassette head 2, the resistor R2 is connected in parallel with the resistor R1.

Also, when switch S is connected to an 8-track head, if switch S2 is opened and resistor R2 is removed from the circuit, the amplifier will receive constant feedback from resistor R1 and will operate at the amplification level appropriate for the 8-track. Can be done.

Therefore, by appropriately selecting the values of the resistors R1 and R7, it is possible to perform width amplification at an optimum degree in any case of an 8-track cassette.

In addition, in order to prevent the bias value from changing when the resistors R and R2 are connected in parallel, the capacitor C1 can be inserted in series with the resistor &, and the capacitor C1 can be inserted in series with the resistor & to perform a DC-like cassette operation so as to perform an AC-like operation.

Figure 2 shows an example in which the switch shown in Figure 1 is switched using the difference in size between the 8-track tape and the cassette tape, and shows the mounting position of the switch.
When using 8-track tape 3 by taking advantage of the fact that the tape is thinner than the track, moveable piece S2 of switch S2
1 and open switch S2 in Fig. 1. In the case of cassette tape 4, since it is thin, it does not reach the movable piece and switch S2 is opened.
2, resistors R2 and R1 are inserted in parallel to the emitter circuit.

In addition, using either the front, rear, left, or right sides where an 8-track tape or cassette tape is stored, we focused on the fact that 8-track tape is thicker and larger, which results in a difference in the storage position of each 8-track tape. It is sufficient to switch the switch when the cassette tape is inserted into the tape recorder, and there is no need to limit the position.

Next, in Fig. 3 a, l), the detection lever 5 is elastically provided on the board 6 near the side edge of the insertion surface of each tape.
In the case of a track tape 3, the curved cut surface 3' of the leading end is used to release the detection lever 5 to the side, as shown in figure a, and in the case of a cassette tape 4, the front corner end is By pushing and moving the detection lever 5, the drive mechanism including the cassette tape drive protrusion located below can be raised to engage the cassette tape 4.

You can also use operational insertion, for example in the case of 8 tracks, press the V-groove of the tape. Since the roller acts,
An actuation plate may be provided that directly or indirectly operates the movable piece of the switch in conjunction with its attachment.

[Brief explanation of the drawing]

FIG. 1 is a partial circuit diagram showing the operation of the switch according to the present invention, and FIG. 2 is a simplified diagram showing the relationship between the switch and the difference in the storage positions of a cassette cart and an 8-track tape according to the present invention. Further, FIGS. 3a and 3t) are top views in the case of detection using the difference in shape of the front surface when an 8-track tape and a cassette tape are inserted. In the figure, 1 is an 8-track head, 2 is a cassette head,
S1 is a changeover switch, S2 is an on/off switch, S2 is a movable piece, R1 and R2 are emitter resistors, Tr1 is an amplifying transistor, 3 is an 8-track tape, and 4 is a cassette tape.

Claims (1)

[Scope of utility model registration request] In an 8-track tape recorder for cassettes, a changeover switch is arranged to adjust the resistance for adjusting the degree of intensification using differences in the size, thickness, or operation of these tapes. Amplifier switching device.