Why are we so insistent on electrostatic speakers? Well, first of all, there’s the question of sound quality.
But a particular sound isn’t yet a wave motion of the air; it doesn’t yet get the eardrums vibrating. But a created sound about to come into being does the rounds of the neurons and the synapses. It dances around loftily or stealthily in the cranial universe of the composer or the performer. STAX earspeakers trace this sound. The method employed in this connection has to be electrostatic, because delicate sounds must not get lost. Delicate sounds are important elements of textural recreation. The main issue faced by pure audio is its re-creativity capacity. The question is how to convert the delicate opening wave patterns that determine tonal quality faithfully into air vibrations. This is the principal merit of electrostatic speakers. This is the only system that has the potential to recreate the most minute nuances with complete accuracy. SR-007 MK2 is the flagship model that aims to achieve the peak among STAX electrostatic speakers. They possess strong drive power in respect to the diaphragm due to the provision of an area in which there are no holes whatsoever on the outer ring of the electrodes (fixed poles) that were completed after an extended process of design and productions of prototypes. They succeed to the new generation units that realize a high degree of linearity in the aperture area. After attachment to a thick insulated resin case, they are fixed to a strong aluminum machined enclosure and shut out unwanted vibration. The cable is designed with the most appropriate structure for transmitting signals to the electrostatic transducer, and use is made of STAX original cables employing high-purity PC-OCC conductors that achieve outstanding sound quality due to their extreme thickness and low capacity. The new product SR-007 MK2 features improvements to the connecting area between the unit and the cable and achieves further improvements in transmission capacity and reliability. The mechanism unique to the SR-007 series whereby the enclosure and the ear pads rotate independently of one another makes it possible to achieve a positioning that exactly fits the ear shape of each individual listener. Where do the music of the spheres and the vibration of the cosmos begin and end?
Setting a section without any holes whatsoever on the perimeter of the electrodes makes it possible to achieve a deeper and more dynamic expressive capacity. There is strong drive power in respect to the diaphragm, and a high degree of linearity is achieve in the opening section too.
As is the case with ordinary speaker systems, the sturdiness of the enclosure is important for earspeakers. After enclosing the sound-producing unit in a thick insulated resin case, it is fixed to a solid metal enclosure. All unnecessary vibration is excluded.
A structure is adopted whereby the enclosure and the earpads are able to rotate independently. This enables positioning that exactly fits the shape of the ears.
An original cable developed with the aim of achieving an even higher level of reproduction is provided.
The conductors make use of high-purity PC-OCC. Outstandingly high sound quality is achieved through the extreme thickness and wide and low capacity.
Specifications of SR-007MK2 Electrostatic Earspeakers
●Type: Push-pull electrostatic open-air type headphone
●Frequency response : 6 to 41,000 Hz
●Impedance : 170 KΩ (at f = 10 KHz)
●Capacitance : 94pF (including cable)
●Sensitivity : 100 dB / 100 V r.m.s. at f = 1 KHz
●Bias voltage : 580 V / DC
●Left & Right Channel identifications :
Left (L) and Right (R) indicators are provided at the cable en trance points on the Earspeakers.
The left channel cable is marked with a solid Line.
The right channel is marked with a dotted Line.
●Ear pads : Real leather (Lamb) used on a part coming into contact with the skin.
High-quality leather used for the surrounding part.
●Cable : 2.5m, PC-OCC, wide, low capacitance cable
●Weight : 365 g (Body) , 512g (Including cable)
●Operating temperature range: 0 to 35
●Humidity range for use: Less than 90% (without condensation)
The joy of pure balance amplification
The operational principle of the electrostatic condenser type is based on a system whereby plus and minus output signals are input by push-pull into two electrodes sandwiching a diaphragm with a high level of accuracy and equidistantly, resulting in the vibration of an ultra-thin membrane through the repulsive force and suction force of static electricity, which is then converted into sound. The balance method, which is considered to be the ideal for amplification, is thus extended to speakers. The electrostatic system entails input by balance, output by balance, and sound conversion by balance, and, in realizing all these features, constitutes the perfect balance system. It is the only system that makes it possible to listen to sound in the ideal manner permitted by the balance system. The new SRM-007tII is our flagship model of a driver unit intended exclusively for earspeakers characterized by their wide range, high dynamic range and outstanding operating features with full allowance made for SACD and other new-generation high-density formats. The ultra-light polymer film, only a few microns thick, realizes unprecedented response and a high degree of resolution. Since it is driven on all sides, there is almost no partitioned vibration and there is no phase distortion. Nor is there any imbalance in the sound quality of the unit or distortion caused by the network. Electromagnetic distortion also does not occur. It opens up on the world of high sound quality that is the mark of headphone listening, a world characterized by the absence of need for large output, the high degree of freedom permitted by the use of high sound quality elements for use with small signals, and the even balance between left and right unaffected by acoustic conditions in the listening room.
●We’ve taken another look at circuit constants and achieved a higher grade of reproducibility for SACD and other new-generation audio formats.
●Consists of a pure balance amplifier in which the XLR balance input does not have to pass through a transformer, an inversion amplifier, etc.
●Makes use of a simple two-stage amplification structure based on rigorously selected low-noise FET. The load resistance makes use of non-inductive coil resistance manufactured by Dale, thus realizing straightforward properties that take advantage of the features of vacuum tubes and outstanding sound quality with a high level of clarity.
●The output stage is designed to lower impedance by using a rigorously selected high voltage dual triode (6FQ7 type) in parallel connection, which has resulted in an improvement in dynamic range especially in the high frequency.
●The heater power source for the vacuum tube makes use of a power circuit of the DC ignition type using an electrolytic condenser and a high-speed Schottky barrier diode, bringing about further improvements in the SN ratio.
●Makes use of a large-capacity power transformer and capacitor.
●Equipped with one XLR (balance) input system and two RCA (imbalance) input systems, meaning that there is a total of three input systems.
●In the case of the RCA input, switching with the earth side ensures that there is almost no interference between devices.
●Use is made of a high sound quality quadruple volume unit which makes possible XLR input as well as all kinds of line level analog voice inputs.
●The RCA terminal “Input 1” is equipped with parallel output terminals and enables input throughout. Connection with other pre-amplifiers and recording decks, etc., is also possible.
●Frequency response DC-100 KHz / +0, -1.5 dB 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
●Amplification 54 dB (x 500)
●Total harmonic distortion 0.01% / 1 KHz, 100 V r.m.s. output SR-007 or SR-404 Signature, when using 1 unit
●Input impedance 50 KΩ / XLR balance 50KΩ×2
●Number of inputs RCA×2, XLR×1 (balanced)
●Maximum output voltage 340 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 55 W
●Temperature range for use Between 0º and 35ºC, max. 90% (no condensation)
●External dimensions 195 (w) x 103 (h) x 420 (d) mm (including VR knob and pin jack (20 + 10)
●Weight 4.7 Kg
●Vacuum tubes 6FQ7/6CG7 type x 4