Pioneer стерео усилитель sa 910

By the positive/negative 2 power-source scheme, since the input point and the outputting point were always kept close to a zero potential, the shocking noise generated at the time of a switching of a switchpoint became near that there is nothing.
With the low section to which the large amplification part of gain comes for a subsequent stage like especially the equalizer stage, it has a big semantics.

The output stage of an equalizer amplifier is adopting an SEPP circuit, an allowable input becomes large at the same time a power-source utilization factor becomes high and is acquired by a low distortion in high output, and the dynamic margin is large.

Direct-current stability which is a low distortion and was excellent over the wide band is realized having adopted the differential amplifier as the first rank and having applied 100% of direct current NFB.
Moreover, it is difficult to place the deviation of the operating point also to a transitional input.
The can shielding type of a low noise selected carefully is adopted as a transistor, and the preventing of the variation per hour of the noise especially by humidity is coped with.

Little nichrome vapor-deposition metal film resistor (1% of error) with error and styrene capacitor (2% of error) are adopted as the part which receives the NFB element and NFB for obtaining a RIAA curve.

An input circuit is equipped with two circuitries for Phono and AUX, Phono2 is prepared Phono1 and AUX1 and the level-control circuitry is prepared AUX2 straight.
Level doubling is made when performing the compare audition of two kinds of cartridges from which an Output voltage differs with two players (or twin tone arm), if especially the level control of Phono2 is applied.
Since the quantity of NFB is performing the coordination of the level control, even when a high-output cartridge is carried out, it has it and this control is extracted, it is considered that a dynamic margin does not run short.
Moreover, the termination of Phono2 can choose an input impedance as three steps, 25kohms, 50kohm, and 100kohm, and can choose the optimal value according to the kind of cartridge.

Two tape decks are connected simultaneously and the duplicate not only from a tapes to a mutual play but a tapes can carry out by the change of a switchpoint.

The tone control is the twin tone control matched for each each side with the still smaller thumb for Bass and Treble.
If a general tone control can be performed, a main will be made into a flat, if the big thumb (main) by the side of inside is turned, and the small thumb (factice) of each sides is turned, super-low-pass one and a super-high region will be controlled.
Thus, the property which was not made until now is controllable by considering it as the tone control which can control two properties.

The main control serves as 11 position switchover type of a 2dB step. The conditioningregulation of Ѓ>10dB (10kHz) of Bass is possible for Ѓ>10dB (100Hz) and Treble.
Moreover, by a flat position, since a capacitor separates from a NFB circuitry and it is only resisting, the frequency characteristic becomes a flat.

The control from which 50Hz and Treble are a 2dB step and seven positions in 20kHz, and Bass becomes independent of regardless of a Main control within the limits of Ѓ>6dB is possible for a Sub control.
Moreover, if it combines with Main and applies, about 6000 kinds of controls are possible.

Regardless of the position of a control of Main and Sub, the tone-defeat switchpoint which makes the frequency characteristic a flat by a quick action is carried.

The 3 steps of first rank differentials hardwired-connection circuitry where the direct current NFB is applied 100% is used for control amplifier like an equalizer amplifier.
The part which used the can shielding transistor with few variations per hour of a noise to the first rank differential amplifier, and it is reliable and was selected carefully is used.

The low filter serves as a three-step change type of 30Hz / subsonic speed / off. Moreover, the high filter can switch three positions of 12kHz / 8 kHz/off. They are 12 dB/oct, respectively.
The transient which constitutes especially the High filter from a passive element of L and C, and tends to become a problem in a high frequency band is excellent.

The level set organization in which the adjustable range of a volume is expandable is carried.
Even when lowering level to -15dB and -30dB and hearing it with a small sound volume with the set thumb formed on the main volume and the coaxial, a volume coordination can carry out near a center (angle near 12:00 of a clock).
Since the relationship of angle of rotation of a loudness level of sound and a volume will change if a level set is switched, the operating range of a loudness contour also interlocks and it changes.
When the thumb of a level set is 0dB, a loudness works from Min of volume control to 40%. Moreover, in the location of -15dB, a loudness works to 60% of volume control, and a loudness works in all the spans in the location which is -30dB.

A whole page hardwired-connection pure complimentary OCL circuit system is used for a power amplifier part, and also it is adoption of two steps of differential amplifier, and a bias warranty circuitry, and has acquired stability.
The first rank differential amplifier is considered so that variations per hour, such as a noise occurrence under the influence of humidity, may not happen by adoption of a can shielding transistor.

The constant current load circuit has received no less than two power circuitries.
A transition of the idle current by variation of supply voltage etc. is suppressed by this circuitry, a transitional crossover distortion is lost, and a low distortion play sound is obtained from the high power time till the minute output.
Moreover, since a noise is pressed down, a large gain can be taken, since the operating point of 2 sets of differential amplifications in front and behind can be chosen the optimal by putting in a current amplification circuitry between constant current load circuits, therefore NFB is applied stably so much, a low distortion and high power are obtained over a large band.

The pure complimentary pair transistor of a driver and the power stage is carrying out the careful selection using of PNP and the NPN type to which a property is good and it was equal.
To the destructive, combined use of the large-sized radiator and current-limiting circuitry and the electronic formula protection network is raising a stability of operation and certainty at the same time it uses what has a high destructive intensity.

The full-scale protection network which combined the relay and the electronic circuitry is carried.
If the protection network operates, the protection lamp of the front panel will light up and bads will be told.
This protection network serves also as the power-source muting at the time of power activation, and makes the shocking noise of the ramp-up period by switchpoint-on there be nothing.

The good power transformer of a regulation and the large capacity power supply capacitor of 15,000 micro Fx2 were adopted as the power-source part, and also the unstable member which originates in a power source by adoption of a constant-voltage-regulated-power-supply circuitry on a driver stage is canceled.

By the change of a speaker, using A, B, C, and 3 sets of speakers independently can also move 2 sets simultaneously with A+B and A+C.
Furthermore, a level control is attached, a control of the sound volume of only the speaker linked to B position is possible for B position, and the change audition of 2 sets of speakers with an efficiency difference etc. can hear and compare it on the same level.
In addition, since the level-control circuitry is located in the preceding paragraph of a power amplifier part, it does not have a variation of the Output load impedance which drives a speaker system by control.

Total is surveyed for fundamental performances, such as power, a distortion, and a remains noise, and the data is attached for every set.

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