Stax SRM-007tII Electrostatic Headphone Amplifier

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.

IMPROVED FREQUENCY RESPONSE
Newly improved circuit raises the frequency response to 100kHz (from 70kHz) to accommodate newer generation audio formats such as SACD and DVD-A.

PURE BALANCE AMPLIFIER
The electrostatic transducer is driven by electrodes set on both sides of the diaphragm which carry the push-pull signals. This is thus virtually the only replay system that enables the listener to enjoy replay unique to balance transmission without the need to pass through a transformer or inversion amplifier.

HEATER POWER SUPPLY
Adopting a rectifier circuits combining low-noise, low-loss Schottky barrier diodes and large electrolytic capacitors. Low-ripple DC power source improves the SN ratio.

OUTPUT STAGE
A simple two-stage amplifier configuration using high-voltage dual triode tube 6FQ7(6CG7) delivers straightforward properties that are transparent and clear sound quality.

INPUT STAGE
Employs Hand pick low noise FET and 6 acoustic high sound quality relays. Simultaneous switching system adopted from SRM-T2 , input source is isolated of direct current and no interference between different devices.

HIGH QUALITY VOLUME CONTROL
High sound quality quadruple volume unit which makes XLR inputs as well as any analog line level inputs possible

SPECIFICATIONS:
Type: Vacuum tube output stage Low noise dual FET input Class A operation, Pure balance DC amplifier configuration Earspeaker driver unit

Vacuum Tube: 4 (6FQ7 / 6CG7)

Frequency Response: DC to 100,000Hz +0,-1.5dB w/ SR-007 or SR-404

High Harmonic Distortion: Max. 0.02% (with 1kHz, 100V r.m.s. )

Gain: 54dB (x500)

Input Terminal: 3 ( XLR x 1, RCA x 2) with 1 RCA parallel out

Rated Input Level: 200mV / 100V Outputs

Max. Input Level: 30V r.m.s. at min. volume

Input Impedance: 50Kohm, 50kohm x 2 during balance

Max. Output Voltage: 340V r.m.s. (1kHz)

Standard Bias Voltage: PRO 580V x 2

Power Voltage Frequency: 117V (50Hz / 60Hz)

Power Consumption: 55W

Temperature & Humidity: 0 to 35ºC / 90% max. without condensation

Dimensions: 7.7 (W) x 4.1 (H) x 16.5 (D) in

Weight: 4.72kg

Color: Silver