вход по аккаунту



код для вставкиСкачать
Patent Translate
Powered by EPO and Google
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.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are each a circuit diagram of each
example of a conventional moving coil type pickup head cornering device, and FIG. 3 is a moving
coil type pickup head according to the present invention. FIG. 2 is a circuit diagram of an
embodiment of an amplifier. C и и и C 5 и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и
и и и и и и и и и и и и и и и и field effect transistor? Output terminal. Figure 1 Figure 2 Figure 13-3-49-109
506 (2) Figure 3-14
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moving coil type
pickup head amplifier, and it is an object of the present invention to provide an amplifier capable
of preamplifying a minute input coming from the above moving coil type pickup with good sound
quality. . In record reproduction, as a conventional MC (moving coil) type pickup head amplifier,
an emitter grounded amplifier with a transistor fed back to the base from the collector, or 55 in
FIG. 1, <? Base grounded tank 1 'Jim consisting of r, etc. Also a gate grounded amplifier
consisting of a field effect transistor FIT1 (1) etc. as shown in FIG. 2 has been used 0 However,
these amplifiers have an input coupling path and a bias circuit The large capacity capacitors C3
to C6 are used, and there is an undesirable defect in sound quality as a pickup head amplifier for
handling a minute input voltage. The present invention eliminates the above-mentioned
drawbacks and will be described with reference to FIG. 3 and an embodiment thereof. FIG. 3
shows a circuit of an embodiment of a moving coil type pickup head amplifier according to the
present invention. In the figure, reference numeral 1 denotes a coil of a moving coil type pickup,
and between both ends of the coil, a bird and a load resistor connected in series with each other
are connected. The junctions to the resistor and the bird are connected to ground via the resistor.
On the other hand, the connection point between the coil 1 and the resistor R3 and the
connection point between the coil 1 and the resistance horse are FICT2. It is connected to each
source of FIT3, and resistance R, R, Fi above FKT2. It is also the source resistance of FKT3. Above
FKT2. Each gate of PKT3 is grounded. The drain of the FKT 2 is connected to the positive and
negative sides of the direct voltage source 2 and the drain of the PICT 5 via the drain resistance
(2), and is also connected to the output terminal 3 via the capacitor C1. The sources of 1 mT2
and 5 configured as described above serve as differential amplifiers. When no mechanical
vibration is applied to the above pick-up needle now, FICT2. The DCV source / J is high enough
to cover the variation of FIT3 and the improvement of s / H becomes sufficiently good, and the
current is resistance wind, the drain-source resistance of FICT2 above, the resistance R3 and the
horse series circuit and PBT5. The drain-to-source resistance is shunted substantially equilibrated
to the resistance and to the series circuit of birds. At this time, the bias current for the FET 2.50
differential amplifier is determined by the resistance to the resistor. The resistance of PIT2.11T3
is also covered with this resistance, and the resistance is selected to be a sufficiently high value
to improve the S / H.
Above FET 2. The source of F] CT 3 is at the same potential due to the common source resistance,
the upper resistance, and no direct current flows in the coil 1 even when the coil 1 and the
amplifier are DC-coupled. (3) Next, at the time of reproducing the record, when mechanical
vibration is given to the needle of the pickup, an AC voltage signal is generated between both
ends of the coil 1, and this signal is a gate grounding type by FIC'F2 + 5 with good
characteristics. It is amplified with good stability by the above-mentioned differential amplifier by
FIT. As described above, since the moving coil type pickup head amplifier according to the
present invention has two gate-grounded differential amplifiers using two PETs, the abovementioned amplifier makes it possible to input minute inputs coming from the pickup. It can be
amplified with high stability, both terminals of the movable coil can be directly connected to the
source of FIT of the gate grounding type differential amplifier, and a large capacity electrolytic
capacitor for input coupling can be eliminated. It has the feature of tendency to be able to
amplify well.
Без категории
Размер файла
9 Кб
jps49109506, description
Пожаловаться на содержимое документа