STAX / SRM-727A

Driver-unit for STAX Headphones

■Driver Unit
■For STAX headphones only
■Semiconductor type
■Frequency response: DC to 115 kHz (SR-007 or SR-404, when using one unit)
■Amplification: 54 dB (500x)
■Harmonic distortion: 0.01% or less (100-10 kHz/100 Vr.m.s. output)
■Input terminal: 1 (RCA⇔XLR)
■Rated input level: 200 mV/100 V output
■Input impedance: 50 kΩ (RCA), 50 kΩ x 2 (XLR)
■Maximum output voltage: 450 Vr.m.s. (1 kHz)
■Standard bias voltage: PRO 580 V x 2
■Operating power supply voltage: AC 100 V ±5%, 50-60 Hz (voltage cannot be changed)
■Power consumption: 46 W
■Operating Ambient Temperature/Humidity: 0-35°C/90% or less

■External Dimensions: (W) 195 x (H) 103 x (D) 420 mm (including knobs and other protrusions)

■Weight: 5.2 kg

■Direct Input with Thru-Out Terminal (RCA)

■Features
~From the Manufacturer's Website~
- The electrostatic system uses drive electrodes sandwiching a polymer film diaphragm a few microns thick, with positive and negative signals input to each for playback. Therefore, connecting to a purely balanced output CD player via XLR allows you to enjoy the true sound of a balanced system without any conversion circuitry.
- The output stage features a newly developed non-NFB, high-current emitter follower and Class A amplifier circuit, delivering more dynamic and vibrant sound quality.
- The emitter follower output stage achieves low impedance, significantly expanding the dynamic range in the high frequencies.

- DC amplifier configuration without coupling capacitors.

- The input stage uses high-quality, low-noise FETs to create a simple two-stage amplification circuit, achieving natural, pure, and rich sound quality.

- A direct switch is also included to avoid volume unit duplication when connecting your preferred attenuator or preamp.

- Parts are used that take sound quality, performance, and the environment into consideration.

- To avoid magnetic distortion, the chassis is made of aluminum, contributing to high sound purity.

- A low amplification level makes it easy to make subtle volume adjustments even when using XLR input or a high-output CD player.

- Equipped with a parallel output terminal that passes the signal directly through.

- A new panel face design features rounded corners and a silver hairline finish.

- Compatible with PRO bias (5-pin) type ear speakers.

- The only control function is volume, and there is only one input system, selecting RCA or XLR. This is a pure ear speaker driver unit that delivers the ultimate in purity.