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NEW PRODUCTS NEWS
electrostatic audio products
Provisional information
New vistas for the non-feedback output stage
The first performance feature required of audio equipment is the capacity to convert air vibrations into sound waves so that the slightest signal can be appropriately heard by the
ear. This means that an essential condition of the vibrating medium, i.e. the diaphragm, in the speaker which constitutes the system of conversion from electrical signal to air vibration is that it needs to be as light as possible. Divided vibration, which is unavoidable in the case of point drive, is possible, as is also ultra-miniaturization if total drive is possible.
Moreover, if headphones are used, there will be reduction in the mass of air that needs to be driven, creating a more ideal situation. The electrostatic type is the system that comes
closest to this ideal. STAX refers to speakers of this type as "earspeakers" and has continuously sought for the ideal form. Since a dedicated unit is needed for drive purposes, the
development of such units is equivalent to the pursuit of high sound quality in the electrical signal system. The matching drive system and the amplifier system are used for driving
electrostatic speakers, and in the case of amplifiers it is possible to build circuits by means of vacuum tubes. In the case of electrical signal systems too, it is generally known that
sound quality varies extensively depending on the circuit configuration, parts, etc. Which should be selected? There is also the element of musicality that needs to be taken into
consideration when determining the sound that is the be-all and end-all of audio. The new SRM-727II employs the drive stage as the semiconductor output and includes an output
stage non-feedback for the first time ever in a STAX driver unit. A pure balance DC amplifier configuration is used for the large current emitter follower A class output stage. A
significant increase in dynamic range especially in the high frequency has been achieved. A high level of sound purity is achieved through the simple two-stage amplifier circuit with
the low-noise FET input stage. This is a brand new driver unit that opens up new vistas for the sense of mass and textural expression supported by a virtually unparalleled degree
of resolution, a natural sense of openness, and a powerful power stage.
■ Features
●The electrostatic method is a playback method which involves the installation of drive electrodes
on either side of a high-polymer film diaphragm with a thickness of only a few microns into each
of which a plus signal and a minus signal are input.
●This means that XLR connection with a pure balance output CD player makes it possible to
listen to the original sound permitted by the balance system without a conversion circuit.
●The output stage has been incorporated by newly developing a non-feedback (NON-NFB) large
current emitter follower A class amplifying circuit. This makes it possible to achieve a much more
vivid and dynamic sound quality.
●The emitter follower at the output stage makes it a possible to achieve lower impedance. A major
expansion in dynamic range in the high frequency has also been achieved.
●DC amplifier configuration without the use of a coupling condenser.
●A high sound quality, low noise FET is used at the input stage with a simple two-stage amplifying
circuit. A natural and pure sound quality with high information quantity is realized.
●Moreover, when connecting your favorite attenuator or pre-amplifier, a direct switch that avoids
duplication of the volume unit is included.
●Use of parts takes account of sound quality, performance and the environment.
●In order to avoid magnetic distortion, the chassis makes use of aluminum materials, thereby
contributing to a high level of purity of sound.
●Amplification is set at a low level, thereby facilitating subtle adjustment of volume during XLR
input and when using high-output CD players, etc.
●Parallel output terminals are included to enable the signal to pass through unhindered. A new
panel face has been designed with rounded corners and a silver hairline finish.
Earspeakers of the PRO bias (5-pin) type can be used.
●
●Control functions are restricted to the volume, and the input uses a single system for selecting
RCA or XLR.
●This is a drive unit for exclusive use with earspeakers with emphasis placed first and foremost
upon purity.
Standard model
Front panel color : Silver
Black front panel
■ Specifications
●Frequency properties: DC-115 KHz / SR-007 or SR-404 Signature, when using 1 unit
●Rated input level: 200 mV / 100 V Outputs
●Maximum input level: 30 V r.m.s. / at Minimum volume (Variable mode)
●Amplification: 54 dB (x 500)
●Total harmonic distortion: Less than 0.01% (1 KHz~10kHz, 100 V r.m.s. output )
●Input impedance: 50 KΩ / XLR balance 50KΩ×2
●Number of inputs: RCA⇔ XLR (balanced)
●Maximum output voltage: 450 V r.m.s. / 1 KHz
●Standard bias voltage: DC 580 V
●Power voltage: 120-240V ±10%, 50 to 60 Hz (adjusted for your area)
●Power consumption: 46 W
●Temperature range for use: 0 to 35℃
●External dimensions: 195 (w) x 103 (h) x 420 (d) mm (including VR knob and pin jack (20 + 10)
●Weight: 5.2 Kg
The standards and external appearance of this unit may be changed without prior notice in order to
make improvements.
STAX LTD.
7-1 Chikumazawa-higashi, Miyoshi-mach, Iruma-gun, Saitama-prefecture, Japan. 〒354-0046
SRM-727II Rear view
TEL:049-258-3988 FAX:049-258-2659
URL:www.stax.co.jp